Embed Size (px)
Citation preview
i
Internship Report
Heavy Mechanical Complex Texila
Submitted By:
Qazi Husnain Qadir 2011-uet-kit-mech-48
Supervisor: Engr. Touseef Asghar
Department of Mechanical Engineering Technology Dr. A. Q Khan Institute of Technology, Mianwali
Affiliated University of Engineering & Technology, Lahore
Session 2011-2015
ii
INTERNSHIP REPORT OF HMC
Supervisor Engr. Touseef Asghar
Designation Lecturer Mechanical
Submitted By
Qazi Husnain Qadir 2011-uet-kit-mech-48
A Project Report submitted in partial fulfillment of the requirements for the award of Bachelors Degree in
Mechanical Engineering Technology
DEPARTMENT OF MECHANICAL ENGINEERING TECHNOLOGY
Nov 2015
iii
Undertaking
I certify that internship report titled “Heavy Mechanical Complex Texila” is my own
work. No portion of the work presented in this report has been submitted in support of
another award or qualification either at this institution or elsewhere. Where material
has been used from other sources it has been properly acknowledged / referred.
Signature of Principal ………………….
Signature of Chairman …………………
Signature of Supervisor ………………..
Qazi Husnain Qadir
2011-uet-kit-mech-48
Class Roll No BS/MT/36
iv
Acknowledgements
I would like to thank Mr Mudaser Chudary guiding me in understanding the
concepts of every machine bay in HMC. I would like to thank all our teachers
especially Engineer Yasir Naveed guiding me in solving our problems related to
internship. our project supervisor Engineer Ttouseef Asghar his cooperation and
support to bring this project to completion.
I would also like to thank our families and friends for their continuous encouragement
and moral support.
v
Abstract
This report is based on the visits of different workshop in HMC, providing
necessary knowledge about the machine and processes which are used in
different shops.
The purpose of this report is to clear the basic concept and try to
explain the process under which products or projects are processed in Heavy
Mechanical Complex Taxila. This report is written under the approach ‘Teach
to Learn’.
vi
Table of Contents
Chapter 1 ................................................................................................................... 1
HMC Introduction ..................................................................................................... 1
1.1 HMC Introduction ............................................................................................ 1
1.2 The complex divided into two major parts ........................................................ 1
1.3 HMC Manufactures Equipment for ................................................................... 2
1.4 The company's capabilities include engineering and manufacturing of .............. 2
1.5 All its processing facilities are in-house including ............................................ 3
1.6 Scope ................................................................................................................ 3
1.7 Working staff ........................................................................................................ 3
1.8 Factories at Heavy Mechanical Complex .................................................................... 4
1.9 Quality policy of HMC ........................................................................................... 4
1.10 Facilities at HMC ........................................................................................... 4
1.11 Production capacity .............................................................................................. 5
1.12 HMC products range ............................................................................................ 5
Chapter 2 ................................................................................................................... 8
Production planning and control ................................................................................ 8
2.1 Responsibility ................................................................................................... 8
2.2 Main activities .................................................................................................. 8
2.3 Dispatch cell ..................................................................................................... 9
2.4 Material management group ............................................................................. 9
vii
2.5 Sub contracting ................................................................................................. 9
2.6 Record keeping ................................................................................................. 9
2.7 Production technology and tool design .............................................................. 9
2.8 Sales order numbering system ............................................................................... 10
2.9 Core planning section ........................................................................................... 10
2.10 Material management ........................................................................................ 11
2.10.1 MMG Section ......................................................................................... 11
2.10.2 General Store .......................................................................................... 11
2.11. Production Technology ...................................................................................... 12
2.11.1 Feasibility/Quantitative detail ................................................................. 12
2.11.2 Process planning .......................................................................................... 12
2.11.3 Tool designing ........................................................................................ 12
2. 11.4 Dispatch cell ............................................................................................... 12
Chapter 3 ................................................................................................................. 13
Mechanical works .................................................................................................... 13
3.1 PPS (production planning section) .................................................................. 14
3.2 ENGINEERING DRAWING ......................................................................... 14
3.2.1 THREE-DIMENSIONAL DRAWING ..................................................... 14
3.2.2 ELLIPSES ................................................................................................ 17
3.2.3 TWO-DIMENSIONAL DRAWING......................................................... 17
3.3 Basic Machine shop ........................................................................................ 24
viii
3.3.1 MACHINING OPERATIONS AND MACHINING TOOLS ................... 26
3.3.2 Machining: ............................................................................................... 26
3.3.3 Types of gear manufacturing in Machine shop .......................................... 27
3.3.4 Lathe machine. ......................................................................................... 30
3.3.5 Types of lathe Machine. ........................................................................... 43
3.3.6 Gear Hobbing Machine............................................................................. 45
3.3.7 Horizontal Boring Machine ...................................................................... 46
3.3.8 MILLING MACHINE .............................................................................. 47
3.3.9 DRILLING MACHINE ............................................................................ 49
3.3.10 Shaper .................................................................................................... 52
3.3.11 Planer ..................................................................................................... 54
3.3.12 GRINDING MACHINES ....................................................................... 55
3.3.13 Slotting machine ..................................................................................... 56
3.3.14 Overhead cranes ..................................................................................... 58
3.4 ASSEMBLY SHOP ........................................................................................ 59
3.4.1 Important Terms used in Limit System ..................................................... 59
3.4.2 Fits: .......................................................................................................... 63
3.4.3 Basis of Limit System............................................................................... 65
3.5 Tool Room ..................................................................................................... 66
3.5.1 Tools and Dies.......................................................................................... 67
3.5.2 Equipment’s use in Tool Room ................................................................. 67
ix
3.6 Heat treatment and TTC (Technical Training Cell) ......................................... 68
3.6.1 Heat treatment – the processes........................................................................... 68
3.7 TTC (TECHNICAL TRAINING CELL) ........................................................ 74
3.8 CTC Fabrication shop ..................................................................................... 76
3.9 Fabrication shop ............................................................................................. 77
3.9.1 Welding .................................................................................................... 79
Chapter4 .................................................................................................................. 83
Foundry & Forge Works .......................................................................................... 83
4.1 PATTERN SHOP ............................................................................................... 84
4.1.1 Types of Pattern ....................................................................................... 85
4.1.2 Types of Core Prints ................................................................................. 87
4.1.3 PATTERN ALLOWNCES ....................................................................... 88
4.2 CAST IRON & STEEL FOUNDARY ............................................................ 89
4.2.1 CAST IRON & STEEL FOUNDARY ...................................................... 90
4.2.2 Sand Casting: ........................................................................................... 92
4.2.3 Foundry Process: ...................................................................................... 92
4.2.4 To carry out the sand molding process: ..................................................... 94
4.2.5 Procedure of Sand Casting: ....................................................................... 96
4.2.6 Advantages of Sand Casting: .................................................................... 96
4.2.7 Safety Precautions: ................................................................................... 97
4.3 Forging Shop .................................................................................................. 99
x
4.3.1 Forging shop I .......................................................................................... 99
4.3.2 Forging shop II ....................................................................................... 100
4.3.3 Forge ...................................................................................................... 100
Chapter5 ................................................................................................................ 108
Quality Assurance & Control ................................................................................. 108
5.1 Non Destructive Testing Lab (NDT Lab) ...................................................... 109
5.1.1 Radiography Techniques ........................................................................ 109
5.2 MATERIAL TESTING LABORATORY ..................................................... 113
5.3 Quality Control Inspection ............................................................................ 115
5.3.1 Inspection tool mostly used are: .............................................................. 115
5.4 ISO 9001 ...................................................................................................... 118
5.4.1 Benefits of ISO 9001 .............................................................................. 118
5.4.2 Some of the benefits to your organization: .............................................. 119
5.4.3 Some of the benefits to your customers:.................................................. 119
5.4.4 ISO 9001 Assessment Process ................................................................ 119
5.4.5 Other things you will need to consider .................................................... 120
5.4.6 ISO 9001 Regular Auditing Procedure .................................................... 121
5.4.7 During the audit you will be assessed on: ............................................... 121
xi
List of Figure
Figure3. 1: One-point perspective drawing .............................................................. 16
Figure3. 2 Two-point perspective drawing ............................................................... 16
Figure3. 3 An isomeric ellipse ................................................................................. 17
Figure3. 4 Drawing sheet ......................................................................................... 21
Figure3. 5 Basic Line Type ...................................................................................... 22
Figure3. 6 Machine Shop ......................................................................................... 24
Figure3. 7 Turning ................................................................................................... 26
Figure3. 8 Shaping, Planning and Sawing ............................................................... 27
Figure3. 9 Gear Shaper ............................................................................................ 27
Figure3. 10 Spur Gears ............................................................................................ 28
Figure3. 11 Helical gears ......................................................................................... 28
Figure3. 12 Internal gear .......................................................................................... 29
Figure3. 13 Worm Gears ......................................................................................... 30
Figure3. 14 Lathe machine ...................................................................................... 31
Figure3. 15 Four jaws chuck .................................................................................... 32
Figure3. 16 Three jaws chuck .................................................................................. 33
Figure3. 17 drill chuck ............................................................................................. 33
Figure3. 18 Collet chuck .......................................................................................... 34
Figure3. 19 Faceplate .............................................................................................. 34
Figure3. 20 Steady Reast ......................................................................................... 36
Figure3. 21 Facing ................................................................................................... 37
Figure3. 22 Straight turning ..................................................................................... 37
Figure3. 23 Parting .................................................................................................. 38
xii
Figure3. 24 Contour Turning ................................................................................... 38
Figure3. 25 Chamfering ........................................................................................... 39
Figure3. 26 Threading ............................................................................................. 39
Figure3. 27 Taper Turning ....................................................................................... 40
Figure3. 28 Boring................................................................................................... 40
Figure3. 29 Form Turning........................................................................................ 41
Figure3. 30 Drilling ................................................................................................. 41
Figure3. 31 Knurling ............................................................................................... 41
Figure3. 32 Turret lathe ........................................................................................... 43
Figure3. 33 Faceplate Lathe Machine ...................................................................... 44
Figure3. 34 Heavy duty lathe ................................................................................... 44
Figure3. 35 Boring Vertical Turret lathe .................................................................. 45
Figure3. 36 Hub Cutter ............................................................................................ 46
Figure3. 37 Horizontal Boring Machine ................................................................... 46
Figure3. 38 MILLING MACHINE .......................................................................... 47
Figure3. 39 Radial drilling machine ......................................................................... 51
Figure3. 40 Bench and Column or Pillar type drilling machines ............................... 52
Figure3. 41 Shaper................................................................................................... 53
Figure3. 42 Planer ................................................................................................... 54
Figure3. 43 Double-housing planers ........................................................................ 55
Figure3. 44 GRINDING MACHINES ..................................................................... 56
Figure3. 45 Slotting machine ................................................................................... 58
Figure3. 46 Overhead cranes ................................................................................... 59
Figure3. 47 Tolerance Zone ..................................................................................... 61
Figure3. 48 Type of fit ............................................................................................. 63
xiii
Figure3. 49 Basis of limit system ............................................................................. 66
Figure3. 50 Annealing ............................................................................................. 69
Figure3. 51 Normalizing .......................................................................................... 69
Figure3. 52 Hardening ............................................................................................. 70
Figure3. 53 Induction hardening .............................................................................. 71
Figure3. 54 Carburizing ........................................................................................... 72
Figure3. 55 Phosphatin ............................................................................................ 73
Figure3. 56 Gas tungsten arc welding ...................................................................... 79
Figure3. 57 MIG Welding........................................................................................ 80
Figure3. 58 Submerged arc welding ......................................................................... 81
Figure3. 59 SMAW Welding ................................................................................... 82
Figure4. 1 pattern .................................................................................................... 84
Figure4. 2 Wood pattern .......................................................................................... 85
Figure4. 3 Metallic patterns ..................................................................................... 86
Figure4. 4 Bellow .................................................................................................... 94
Figure4. 5 Rammer .................................................................................................. 94
Figure4. 6 Hand riddle ............................................................................................. 95
Figure4. 7 Trowel .................................................................................................... 95
Figure4. 8 Shovel .................................................................................................... 95
Figure4. 9 Flask ....................................................................................................... 96
Figure4. 10 Hot Die ............................................................................................... 101
Figure4. 11 Cold die .............................................................................................. 102
Figure4. 12 Hammer Forging ................................................................................. 103
Figure4. 13 Hydraulic Forging Press:..................................................................... 104
xiv
Figure4. 14 Manipulator ........................................................................................ 105
Figure4. 15 CRANES ............................................................................................ 106
Figure4. 16 FURNACES ....................................................................................... 106
Figure5. 1 Radiography Techniques ....................................................................... 109
Figure5. 2 Ultrasonic Testing Method .................................................................... 111
Figure5. 3 Eddy current testing method ................................................................. 111
Figure5. 4 Liquid penetrate testing method ............................................................ 112
Figure5. 5 Magnetic particle testing method .......................................................... 112
Figure5. 6 VERNIER CALIPER: ......................................................................... 116
Figure5. 7 MICROMETER ................................................................................... 117
1
Chapter 1
HMC Introduction
1.1 HMC Introduction Heavy Mechanical Complex (Private) Limited is a leading engineering goods
manufacturing enterprise in Pakistan located at Taxila about 30 Kilometers north of
capital Islamabad. It is a professionally managed progressive organization with over
160,000 sq. meters covered facilities and 1,100 employees.
Heavy Mechanical Complex Ltd. (HMC), Taxila is a major heavy engineering
subsidiary of the State Engineering Corporation (SEC) under the Ministry of
Industries & Production, Government of Pakistan. The Heavy Mechanical Complex
(HMC), the biggest undertaking of its type in Pakistan, was established in 1969 with
Chinese assistance.
HMC is ISO 9001certified and is authorized to use ASME 4 stamps U, U2, S &
PP for equipment manufactured according to ASME code. The manufacturing is
backed by excellent quality control and testing facilities to meet the product and
customer quality requirements. 3rd party inspection facilities are also available, where
required.
1.2 The complex divided into two major parts H.M.C (Heavy Mechanical Complex)
H.F.F (Heavy Forge Factory).
The Heavy Forge Factory (HFF) at this complex has proved crucial for Pakistan's
defense production needs.
HMC has the capability for designing, engineering and manufacturing of industrial
plants and machinery. HMC has the largest fabrication and machining facilities in the
2
country equipped with Computer Aided Designing (CAD) and can undertake a variety
of fabrication / machining jobs on sub-contracting basis.
1.3 HMC Manufactures Equipment for Hydro-electric power plants,
Thermal power plants,
Sulphuric acid plants,
Industrial alcohol plants,
Oil & gas processing plants,
Chemical & petro-chemical plants,
Boilers,
Cranes,
Construction machinery,
Material handling equipment,
Steel structure,
Railway equipment,
Some of the other products which are produced on regular basis.
1.4 The company's capabilities include engineering and manufacturing of
Sugar Mills ranging between 1,500 - 12,000 TCD (tons of cane crushing
capacity per day),
Portland Cement Plants of 700- 5,500 TPD (tons per day)
Module and White Cement Plant of 50 - 1,000 TPD.
HMC have the resources to handle large projects with demanding delivery schedules.
Being the largest and most extensive fabrication and machining facility equipped with
state of the art technology. HMC provide manufacturing services to the customers.
3
HMC have gained rich experience in designing and manufacturing of large projects
through collaboration with internationally reputed engineering organizations.
1.5 All its processing facilities are in-house including Designing,
Fabrication,
Machining,
Iron and Steel Castings,
Forgings,
Heat Treatment,
Assembly,
Sand Blasting,
Painting
Galvanizing.
1.6 Scope This procedure defines the system for
Production Planning and Control (PPC),
Production technology,
Material management,
Dispatches,
Finish goods,
Store keeping and services.
1.7 Working staff HMC is a professionally managed progressive organization with 1100 employees.
HMC has a total covered area of 160,000 square feet.
4
1.8 Factories at Heavy Mechanical Complex
Heavy Mechanical Complex I (HMC I)
Heavy Forge and Foundry works (HMC II)
Heavy Mechanical Complex II (HMC III)
Of these the last one is directly under the ministry of defense while the former two
are governed by ministry of production.
1.9 Quality policy of HMC
HMC states its quality policy as follows:
“ Q ua l i t y pe r f o r ma nc e i s c om m i t t e d to e xc e l l e nc e b y e a ch
c o mp a n y em pl o ye e . I t i s achieved by team work and through a process of
continuous improvement.”
“We are dedicated to being seen as an organization which provides quality
products and services which meet or exceed the expectations of our customers.”
1.10 Facilities at HMC
There are several shops in HMC industry which are:
Design department
Production planning and control (PPC)
Sales department /(PMD i.e. Project Management Department)
5
Accounts Finance and Administration
Machine shop
Heat treatment shop
Fabrication shop
Forging shop
Hydraulic press shop
Steel foundry
Cast iron foundry
Pattern shop
Maintenance shop
Quality control
1.11 Production capacity Machining capacity = 500ton *12 months
Fabrication and Machining capacity = 1000ton *12months
Total = 500*12 + 1000*12 = 6000 tons per annum
This production capacity can be increased time to time with the extension
of man power and other sources subjecting to sub contractors.
1.12 HMC products range HMC specializes in Engineering, Designing, Manufacturing, Installation and
Commissioning of plants and machinery including:
Cement plant and spares
600-5000 TPD (tons per day)
Sugar plant and spares
500-12000 TCD (tons of cane crushing capacity per day),
Process plant equipment
6
Pressure Vessels,
Columns,
Heat Exchangers,
Drums,
Storage Tanks and Kilns
Chemical & Petro-Chemical plants
Sulphuric Acid Plant,
Basic Chromium Sulphate Plant,
Industrial Alcohol distillery,
Gas Dehydration,
LPG, Gas Purification
Sulphur Recovery Plants.
Industrial boilers
Fire tube Package units,
Water tube package units,
Heat recovery boilers,
Begasse fire boilers (capacity up to 200 T/hr)
Thermal power plants
Equipment for utility boilers,
Membrane wall,
Turbine/generator parts
Hydral power plants
Gates,
Penstocks,
Wicket gates,
7
Head covers,
Turbine/generator parts
Cranes
Electric overhead travelling crane,
Portal & mobile cranes
Road construction machinery
Static & vibratory road rollers,
Asphalt mixing plant
Steel structures
For thermal power plants,
Process plants
Railways equipment
Railway axles,
Screw coupling & screw jack
Castings
Iron & steel castings as per specifications
Forgings
Shafts,
Rings
Others as per specifications
Automotive forging
For tractors
Other automobile
8
Chapter 2
Production planning and control
2.1 Responsibility GM is responsible for all activities of department who was delegated responsibilities
and authorities to respective officers, incharge and report to GM.
Ensure implementation of procedures, sub procedures and work instructions
relating to PPC activities.
Implement HMC quality policy in areas and activities relating to PPC
department.
Continuously improve system and procedures. Any change in procedure is
subjected to approval of head of the department.
2.2 Main activities To maintain balance order position
Heat treatment
Annealing
Normalizing
Hardening
Tempering
Carburizing
9
2.3 Dispatch cell Arrangement of packing, loading and transportation of the entire outgoing
product as per contract.
Provision of material handling, panting and packing services to the concerned
section / department.
2.4 Material management group Inventory planning, material control and indenting of new material.
Storage of all inventories, receipt of incoming stores and maintain current
balance.
2.5 Sub contracting Sub contracting of complete or part of work for carrying out specific jobs of
fabrication, machining, sand blasting, painting, galvanizing and
erection/installation.
2.6 Record keeping Individual section incharge are responsible to maintain record as per HMC
procedure.
Shop scheduling, monthly sale and production report.
Preparation of sale and production budget reports as well.
Periodic report for management information system for weekly fellow up of
production and sale review meeting.
2.7 Production technology and tool design To carry out feasibility as well as work out for quantitative details.
Process planning, preparation of detail parts list, rout cards
10
2.8 Sales order numbering system The sales order numbering system allocates a unique identification system to each
order acquired by the sales and marketing department. This sales order consists of
six digits. The first two of these numbers designate the product group number of
the products to be manufactured or services to be provided by the organization.
The next two digits specify the fiscal year in which the order is received and the
last two digits give the number of similar orders already received in the same
fiscal year.
For example, a job order given as 111004
11-10-04 is read as follows:
11_product group no for sugar spares
10_represents 2010 as the fiscal year
04_specifies the fourth order for the current year
That is fourth order of sugar spares in 2010.
2.9 Core planning section Master schedule planning
Order activity planning
Monitoring all schedules / shop scheduling
Preparing various reports for MIS
Maintenance of balance order position
Monthly sales and production report
Sales / production budget
Project review, meeting and follow up
Data entry, loading data and processing data
11
2.10 Material management
2.10.1 MMG Section Material requirement planning
Indenting and follow up of indents
To keep update purchase status for all the project demands
Establish stock levels for general consumable items and raw materials
Issuance of materials to the appropriate job
To keep and maintain update levels for the store items
To look after stores and related things
2.10.2 General Store To receive, issue all the materials and equipment in stores as per laid
down procedure
Maintain detailed record of store movements
Maintain stock location system
Maintain daily submission of issue and receipt statement to concerned
department to keep store areas secure and organized
12
2.11. Production Technology
2.11.1 Feasibility/Quantitative detail Feasibility study and quantitative details of client’s requirements for cost
estimate.
2.11.2 Process planning Prepare details per list, route cards, cutting plans, time sheets and process
maps for all the processes.
2.11.3 Tool designing Designing of all types of press tools, dies, templates, jigs and fixtures.
Prepare drawings for machinery components, cutting planes, marking
templates for shops etc.
2. 11.4 Dispatch cell To receive finished jobs from shops
To draw standard items from store for dispatch to customer
To organize packing etc
To organize transportation
Ensure complete accurate documentation with each product
13
Chapter 3
Mechanical works
3.1 Production Planning Section (PPS)
3.2 Engineering Drawing
3.3 Basic Machine shop
3.4 Assembly Shop
3.5 Tool Room
3.6 Heat treatment
3.7 TTC (Technical Training Cell)
3.8CTC (Center Technical Cell) Fabrication shop
3.9 Fabrication shop
14
3.1 PPS (production planning section) PPS stands for production planning section. This section is known as main section of
machine shop working of this section given below in some points...
Job order receiving from PPC
Drawing set receiving from PPC
Cutting plan receive if required.
Drawing planning / job order receiving
Material receiving.
Loading
Inspection
Movement
3.2 ENGINEERING DRAWING Introduction
Engineering industry is branching of mechanical engineering and industrial
engineering itself is a discipline that studies on the design, repair, manufacturing
systems, industrial management and installation of integrated systems consisting of
human, machine, methods, tools, materials, information, and energy. This discipline is
supported by knowledge of mathematics, physics, social sciences, and the principles
and methods of design analysis and design to build and repair the system.
3.2.1 THREE-DIMENSIONAL DRAWING The types of three-dimensional representation drawings that are relevant to this study
include praline (isometric and plan metric) and perspective (one and two point).
15
1. PARALINE DRAWING
Objects are drawn with the receding lines remaining parallel to each other (hence the
term ‘Para-line’).
Common types of paraline drawings include
Isometric
Planometric.
Isometric Drawing
Isometric drawings are constructed with both sides receding from the corner edge at
30 degrees. The isometric drawing provides a comprehensive overall view of the
object.
Planometric Drawing
Planometric drawings are very similar to Isometric drawings, however, the base (or
plan) of the object retains its true form (is not altered) with both sides receding at 45
degrees (or one side recedes at 30 degrees and the other at 60 degrees).
2. PERSPECTIVE DRAWING
Objects are drawn in a naturalistic manner consistent with human vision; the receding
lines converge towards the horizon (eye level) rather than remain parallel to each
other. The placement of the horizon line determines the location of the viewer and
16
provides capacity for different views of an object or the relationship of parts to each
other.
One-point perspective
Objects are drawn front on, with receding lines converging to one vanishing point
on the horizon.
Figure3. 1: One-point perspective drawing
Objects are drawn with a corner closest to the viewer and side drawn with
receding lines to two vanishing points on the horizon line.
Figure3. 2 Two-point perspective drawing
17
3.2.2 ELLIPSES The knowledge and understanding of how to draw an ellipse is important to this
study. Whilst ellipse templates can be useful, students should know how to draft a
freehand ellipse for paraline and perspective purposes.
Figure3. 3 An isomeric ellipse
3.2.3 TWO-DIMENSIONAL DRAWING Types of two-dimensional representation drawings applicable to this study include
orthogonal, floor plans and elevations, and packaging nets.
1 .PACKAGING NET
A drawing of a flat two-dimensional shape that when folded becomes a three-
dimensional form. It can also be referred to as a development net. Often a packaging
net will include tabs for stability and fastening. The drawings are to scale and involve
the use of line conventions that indicate fold lines (broken lines) and cutting edge
(solid outline).
18
2. FLOOR PLANS AND ELEVATIONS
Scaled two-dimensional drawings used by architects involving a set of conventions
regarding line types, dimensioning and symbols. Floor plans are views from above,
while elevations refer to views of the side or facade. Please refer to page 20 of this
resource material for further information on Architectural conventions relevant to this
study.
3. THIRD-ANGLE ORTHOGONAL DRAWINGS
There are occasions where a three-dimensional drawing may not provide enough
information about an object to be constructed. Orthogonal drawing is a multi-view
two-dimensional drawing system that resolves this problem. Each view of an object
(front, sides and the base) is drawn separately showing only two dimensions, but is
kept aligned and to the same scale. Combining multi views allows all three
dimensions to be considered.
Third-angle projection refers to the layout of views.
The views
Third angle orthogonal drawings can include as many views as required to
communicate the features of an object. In practice only the views required to describe
the object clearly are drawn.
19
The views are known as:
FRONT VIEW
TOP VIEW
SIDE VIEW (left and/or right hand view)
Plan your layout
It is important to plan your drawing/solution and consider placement before you start.
Figure 3.4 shows appropriate positioning using an A3 sheet of paper. Notice there is
also an isometric view positioned in the top right-hand corner. This is often placed
there to provide a connection between the two-dimensional shapes of orthogonal and
more visually representative three-dimensional isometric form.
NOTE: The layout used will vary depending on the information to be communicated.
Consider the size of your paper choice, relative to the scale/dimension of the drawing,
and the orientation. A vertical orientation may better suit taller, thinner objects such
as a jug or drinking vessel.
Placement of views
The TOP VIEW is always directly above the FRONT VIEW and the SIDE VIEWS
are always ‘next to’ and ‘aligned to’ the FRONT VIEW. At times the views can be
placed apart equidistantly.
However, the views can be placed at different distances from the front view,
depending on what information, such as dimensions, needs to be included.
20
If you want to place your views equidistant then you can use the 45 Degree Method to
place and project your views. The following steps describe the process.
1. The FRONT VIEW must be drawn first, then your vertical lines should be
projected to give the width of the TOP VIEW.
2. Project the horizontal lines from the FRONT VIEW to give the height of the SIDE
VIEW being represented.
3. Where the maximum width and height projection lines on the FRONT VIEW meet,
a 45 degree line will need to be drawn.
4. The SIDE VIEW vertical lines will need to be projected to the 45 degree line (these
lines must be 90 degrees). Where these lines meet the 45 degree line they will then
need to return to the TOP VIEW vertical projection lines (these lines must be 180
degrees).
5. All line types should now be present on the TOP VIEW.
6. Referring to the FRONT and SIDE VIEW the various lines will need to be defined
and drawn using the correct line type.
Once completed all views should be equidistant apart.
21
Figure3. 4 Drawing sheet
Labeling orthogonal drawings
In VCE Visual Communication Design, students are required to label each view.
Each VIEW must be labeled using an uppercase, sans serif typeface.
For example GILL SANS typeface (or similar)
VIEW labels are located in a centered position under each view, 10mm below
the view, 5mm height.
LINE STYLES AND CONVENTIONS
The use of different line styles and widths is important in technical drawing as they
are used to indicate details and features in a drawing. Line styles make drawings
easier to read: for example, solid lines used to show the object will stand out from
broken lines used to show hidden information. The Australian Standards incorporates
22
a detailed list of line styles for use in different fields of design including architecture
and engineering. For this study, it is appropriate for students to use a minimum of two
line weights to meet line style conventions.
This will include:
A heavier line to draw the views that represent the object being drawn and
dashed lines to represent hidden lines
A thinner ‘half weight’ line to provide additional information such as centre,
projection and dimension lines.
Figure3. 5 Basic Line Type
DIMENSIONING AN OTHOGONAL DRAWING
Placement of numeric information is known as dimensioning.
You can measure directly from an orthogonal drawing when the scale is 1:1 (full
size). All dimensions are recorded using true size measurements. Where the object
does not fit to the page, reduction ratios are used.
23
These start at 1:2, 1:5, 1:10, 1:20, 1:50 and 1:100 (house) for drawing smaller than
full size.
Where the object is too small to work with easily enlarged ratios are used.
These start at 2:1, 5:1…for drawings larger than full size.
Each drawing needs to indicate the scale.
For example:
SCALE 1:1
ALL DIMENSIONS IN MM OR
SCALE 1:100
ALL DIMENSIONS IN MM
.
Dimension placement
The most important thing about dimensioning is to ensure that the measurements are
placed both logically and clearly. The student should:
Ensure that they have dimensions for the height, width and depth
Ensure that they have included all crucial dimensions that allow the object to
be interpreted
Dimension where the shapes are shown and try to avoid dimensioning hidden
lines
Space dimension lines so that the dimensions are not over crowded
Not over-dimension the work as it can lead to confusion and an untidy
drawing
24
3.3 Basic Machine shop In the development of every nation industries are very important and for industries
machinery is key factor. To check the development of any industry check it`s
machinery.
A machine shop is a room, building, or company where machining is done. In a
machine shop, machinists use machine tools and cutting tools to make parts, usually
of metal.
The production can consist of cutting, shaping, drilling, finishing, and other processes.
The machine tools typically include metal, milling machines, machining centers,
multitasking machines, drill presses, or grinding machines, many controlled
with CNC.
Figure3. 6 Machine Shop
Machine shop Bays:
Small Bay
Medium Bay
Heavy Bay
25
In the machine shop of Heavy Mechanical Complex (HMC) there are nearly 500
machines of different sizes and capacities. The machine shop of HMC contains
various types of machines.
Available Machines:
Lathe machine.
Three jaws
Four jaws
Turret
Face plate lathe machine.
HDL (Heavy Duty Lathe).
BVT (Boring Vertical Turret Lathe).
Gear Hobbing lathe.
Horizontal boring machine
Milling machine.
Drilling machine.
Radial drilling machine.
Column drilling machine.
Shaper.
Planner.
Double housing planner
Slotting machine.
Grinding machine
Overhead Crane
26
3.3.1 MACHINING OPERATIONS AND MACHINING TOOLS Turning and related operations
Drilling and related operations
Milling
Machining centers and turning centers
High speed machining
Other machining operations
3.3.2 Machining: A material removal process in which a sharp cutting tool is used to
mechanically cut away material so that the desired part geometry remains
Most common application :to shape metal parts
Machining is the most versatile and accurate of all manufacturing process in
its capability to produce a diversity of part geometries and geometric features
(e.g. screw threads, gear teeth, flat surfaces).
Classification of Machine Parts
Rotational –Cylindrical or disk – like shape: Achieved by rotation motion
of work part. Ex. Turning and Boring.
Figure3. 7 Turning
27
Non-Rotational - block or plate – like shape: Achieved by linear motion of
work part.
Ex. Milling, Shaping, Planning and Sawing.
Figure3. 8 Shaping, Planning and Sawing
3.3.3 Types of gear manufacturing in Machine shop
Gear Shaper
A gear shaper is a machine tool for cutting the teeth of internal or external gears. The
name shaper relates to the fact that the cutter engages the part on the forward stroke
and pulls away from the part on the return stroke, just like the clapper box on a planer
shaper. To cut external teeth, a different machine called a hobbing machine can be
used.
Figure3. 9 Gear Shaper
28
1. Spur Gears
They connect parallel shafts, have involutes teeth that are parallel to the shaft and can
have internal or external teeth. They cause no external thrust between gears. They are
inexpensive to manufacture. They give lower but satisfactory performance. They are
used when shaft rotates in the same plane.
Figure3. 10 Spur Gears
2. Helical Gears
Helical gears connect parallel shifts but the involutes teeth are cut at an angle to the
axis of rotation. Two mating helical gears must have equal helix angle but opposite
hand. They run smoother and more quietly. They have higher lo
ad capacity, are more expensive to manufacture and create axial thrust. They have
longer and strong teeth. They can carry heavy load because of the greater surface
contact with the teeth. The efficiency is also reduced because of longer surface
contact. The gearing is quieter with less vibration.
Figure3. 11 Helical gears
29
3. Internal Gears
Internal gears are hollow. The properties and teeth shape is similar as of external
gears except that the internal gear had different addendum
and dedendum values modified to prevent interference in internal meshes. They are
designed to accommodate a wide range of equipment. These are ideal and cost
effective. The teeth are cut into the inside diameter while the outside diameter is
smooth. These gears are available only in brass. Internal gear offers low sliding and
high stress loading. They are used in planetary gears to produce large reduction ratios.
When choosing a mating gear the difference between the number of teeth of girth gear
and the pinion should not be less than 15.
Their non-binding tooth design ensures smooth, quiet operation. They are used to
transmit rotary motion between parallel shafts, the shaft rotating in the same direction
as the arrangement.
Figure3. 12 Internal gear
4. Worm Gears
The Worm gear is the heart of most mills and kiln drive system. They can't be used in
spare parts inventory. They are also used in steel industry, sugar industry, paper and
pulp industry. The girth gear has been preferred over the gearless drives due
to their lower initial cost, simplicity to install, operate and maintain.
30
Figure3. 13 Worm Gears
3.3.4 Lathe machine. The lathe is a machine tool used principally for shaping articles of metal, wood, or
other material. All lathes, except the vertical turret type, have one thing in common
for all usual machining operations; the work piece is held and rotated around a
horizontal axis while being formed to size and shape by a cutting tool. The cutter bit
is held either by hand or by a mechanical holder, and then applied to the work piece.
Principal capabilities of the lathe are forming straight, tapered, or irregularly outlined
cylinders, facing or radial turning cylindrical sections, cutting screw threads, and
boring or enlarging internal diameters. The typical lathe provides a variety of rotating
speeds and suitable manual and automatic controls for moving the cutting tool.
Sizes
The size of an engine lathe is determined by the largest piece of stock that can be
machined. Before machining a workpiece, the following measurements must be
considered: the diameter of the work that will swing over the bed and the length
between lathe centers.
31
Figure3. 14 Lathe machine
(a) Parts of The Lathe:
Bed and Ways
Headstock
Tailstock
Carriage
Feed Rod
Apron
Lead Screw
Compound Rest
Tool posts
32
(b) Lathe Accessories
1. Chucks:
Workpieces are held to the headstock spindle of the lathe with chucks, faceplates, or
lathe centers. A lathe chuck is a device that exerts pressure on the workpiece to hold it
secure to the headstock spindle or tailstock spindle. Commonly used with the lathe are
the independent chuck, the universal scroll chuck, the combination chuck, the hollow
headstock spindle chuck, the lathe tailstock chuck, the collet chuck, and the step
chuck. Faceplates, or lathe centers. A lathe chuck is a device that exerts pressure on
the work piece to hold it secure to the headstock spindle or tailstock spindle.
Commonly used with the lathe are the independent chuck, the universal scroll chuck,
the combination chuck, the hollow headstock spindle chuck, the lathe tailstock chuck,
the collet chuck, and the step chuck.
2. Independent Chuck (Four Jaws Chuck):
The independent chuck generally has four jaws which are adjusted individually on the
chuck face by means of adjusting screws. The chuck face is scribed with concentric
circles which are used for rough alignment of the jaws when chucking round work
pieces. The final adjustment is made by turning the work piece slowly and using
gages to determine its concentricity. The jaws are then readjusted as necessary to
align the work piece to desired tolerances.
Figure3. 15 Four jaws chuck
33
3. Universal Scroll Chuck (Three Jaws Chuck):
The universal scroll chuck usually has three jaws which move in unison as an
adjusting pinion is rotated. The advantage of the universal scroll chuck is its ease of
operation in centering the work for concentric turning. This chuck is not as accurate
as the independent chuck but, when in good condition, it will center the work
automatically within 0.003 of an inch of complete accuracy.
Figure3. 16 Three jaws chuck
4. Drill Chuck:
The drill chuck is a small universal-type chuck which can be used in either the
headstock spindle or in the tailstock for holding straight-shank drills, reamers, taps, or
small-diameter work pieces. The drill chuck has three or four hardened steel jaws
which are moved together or apart by adjusting a tapered sleeve within which they are
contained. The drill chuck is capable of centering tools and small-diameter work
pieces to within 0.002 or 0.003 of an inch when firmly tightened.
Figure3. 17 drill chuck
34
5. Collet Chuck:
The collet chuck is the most accurate means of holding small work pieces in the lathe.
The collet chuck consists of a spring machine collet and a collet attachment which
secures and regulates the collet on the headstock spindle of the lathe.
Figure3. 18 Collet chuck
6. Faceplates:
A lathe faceplate is a flat, round plate that threads to the headstock spindle of the lathe.
The faceplates used for clamping and machining irregularly-shaped work pieces that
cannot be successfully held by chucks or mounted between centers. The work piece is
either attached to the faceplate using angle plates or brackets, or is bolted directly to
the plate. Radial T-slots in the faceplate surface facilitate mounting work pieces. The
faceplate is valuable for mounting work pieces in which an eccentric hole or
projection is to be machined. The number of applications of the faceplate depends
upon the ingenuity of the machinist.
Figure3. 19 Faceplate
35
7. Lathe Dogs:
Lathe dogs are cast metal devices used in conjunction with a driving plate or a
faceplate to provide a firm connection between the headstock spindle and the work
piece that is mounted between centers. This firm connection permits the work piece to
be driven at the same speed as the spindle under the strain of cutting. Frictional
contact alone, between the live center and the work piece, is not sufficient to drive the
work piece. Three common types of lathe dogs are illustrated in figure. Lathe dogs
may have bent tails or straight tails. When the bent tail dogs are used, the tail fits into
a slot of the driving face plate. When straight tail dogs are used, the tail bears against
a stud projecting from the faceplate.
8. Steady Rest:
Work pieces often need extra support, especially long, thin work pieces that tend to
spring away from the cutter bit. Two common supports or rests are the steady rest and
the follower rest. The steady rest or center rest, as it is also called, is used to support
long work pieces or shafts being machined between centers or for boring operations.
It is also used for internal threading operations where the work piece projects a
considerable distance from the chuck or faceplate. The steady rest is clamped to the
lathe bed at the desired location and supports the work piece within three adjustable
jaws. The rest prevents the work piece from springing under cut, or sagging as a result
of the otherwise unsupported weight. The work piece must be machined with a
concentric bearing surface at the point where the steady rest is to be applied. The jaws
must be carefully adjusted for proper alignment and locked in position. The area of
contact must be lubricated frequently. The top section of the steady rest swings away
36
from the bottom section to permit removal of the work piece without disturbing the
jaw setting.
Figure3. 20 Steady Reast
9. Follower Rest:
The follower rest is used to back up a work piece of small diameter to keep it from
springing under the stress of the cutting operation. The follower rest gets its name
because it follows the cutting tool along the work piece. The follower rest has one or
two jaws that bear directly on the finished diameter of the work piece opposite and
above the cutting tool. The rest is bolted to the lathe carriage so that it will follow the
cutter bit and bear upon that portion of the work piece that has just been turned. The
cut must be started and continued for a short longitudinal distance before the follower
rest is applied. The rest is generally used only for straight turning or threading long,
thin work pieces
37
(c) Basic Lathe Operations:
1. Facing:
Facing is the square finishing of the ends of the workpiece and is often used to bring
the piece to a specified length. In facing operations, the cutter bit does not traverse
laterally (left or right) but cuts inward or outward from the axis of the piece. Facing of
the ends is usually performed before turning operations.
Figure3. 21 Facing
2. Straight Turning:
Straight turning may he performed upon a workpiece supported in a chuck, but the
majority of workpieces turned on an engine lathe are turned between centers. Turning
is the removal of metal from the external surface of cylindrical workpieces using
various types of cutter tool bits.
Figure3. 22 Straight turning
38
3. Parting:
One of the methods of cutting off a piece of stock while it is held in a lathe is a
process called parting. This process uses a specially shaped tool with a cutting edge
similar to that of a square nose cutting tool. The parting tool is fed into the rotating
workpiece, perpendicular to its axis, cutting a progressively deeper groove as the
workpiece rotates. When the cutting edge of the tool gets to the center of the
workpiece being parted, the workpiece drops off. Parting is used to cut off parts that
have already been machined in the lathe, or to cut tubing and bar stock to their
required lengths.
Figure3. 23 Parting
4. Contour Turning:
Instead of feeding the tool along a straight line parallel to the axis of rotation as in
turning, the tool follows a contour that is other than straight, thus creating a contoured
form in the turned part.
Figure3. 24 Contour Turning
39
5. Chamfering:
The cutting edge of the tool is cut an angle on the corner of the cylinder, forming what
is called a “chamfer”.
Figure3. 25 Chamfering
6. Threading:
A method of producing screw threads that uses a single-point tool to cut a blank or
workpiece as it rotates on a lathe. A pointed tool is fed linearly across the outside
surface of the rotating work part in a direction parallel to the axis to rotation at a large
effective feed rate, thus creating threads in the cylinder.
Figure3. 26 Threading
7. Taper Turning:
In ordinary straight turning, the cutting tool moves along a line parallel to the axis of
the work, causing the finished job to be the same diameter throughout. However,
when cutting a taper, the tool moves at an angle to the axis of the work, producing a
40
taper. Therefore, to turn a taper, the work must either be mounted in a lathe so that the
axis upon which it turns is at an angle to the axis of the lathe, or cause the cutting tool
to move at an angle to the axis of the lathe.
Figure3. 27 Taper Turning
8. Boring:
A single point tool is fed linearly, parallel to the axis of rotation, on the inside
diameter of an existing hole in the part.
Figure3. 28 Boring
9. Form Turning:
In this operation, sometimes called forming, the tool has a shape that is imparted to
the work by plunging the tool radially into the work.
41
Figure3. 29 Form Turning
10. Drilling:
Drilling can be performed on a lathe by feeding the drill into the rotating work along
its axis. Reaming can be performed in a similar way.
Figure3. 30 Drilling
11. Knurling:
This is not a machining operation because it does not involve cutting of material.
Instead, it is a metal forming operation used to produce a regular cross-hatched
pattern in the work surface.
Figure3. 31 Knurling
42
Safety at Lathe Machine
All lathe operators must be constantly aware of the safety hazards that are associated
with using the lathe and must know all safety precautions to avoid accidents and
injuries. Carelessness and ignorance are two great menaces to personal safety. Other
hazards can be mechanically related to working with the lathe, such as proper
machine maintenance and setup. Some important safety precautions to follow when
using lathes are:
Correct dress is important, remove rings and watches, roll sleeves above
elbows.
Always stop the lathe before making adjustments.
Does not change spindle speeds until the lathe comes to a complete stop.
Handle sharp cutters, centers, and drills with care.
Remove chuck keys and wrenches before operating
Always wear protective eye protection.
Handle heavy chucks with care and protect the lathe ways with a block of
wood when installing a chuck.
Know where the emergency stop is before operating the lathe.
Use pliers or a brush to remove chips and swarf, never your hands.
Never lay tools directly on the lathe ways. If a separate table is not available,
use a wide board with a cleat on each side to lay on the ways.
Keep tools overhang as short as possible.
Never attempt to measure work while it is turning.
Never file lathe work unless the file has a handle.
File left-handed if possible.
Protect the lathe ways when grinding or filing.
43
3.3.5 Types of lathe Machine.
1. Turret lathe
The turret lathe is a form of metalworking lathe that is used for repetitive production
of duplicate parts, which by the nature of their cutting process are
usually interchangeable. It evolved from earlier lathes with the addition of the turret,
which is an index able tool holder that allows multiple cutting operations to be
performed, each with a different cutting tool, in easy, rapid succession, with no need
for the operator to perform setup tasks in between, such as installing or uninstalling
tools, nor to control the tool path
Figure3. 32 Turret lathe
2. Faceplate Lathe Machine A lathe faceplate is the basic work holding accessory for a wood or metal
turning lathe. It is a circular metal (usually cast iron) plate which fixes to the end of
the lathe spindle. The work piece is then clamped to the faceplate, typically using t-
nuts in slots in the faceplate, or less commonly threaded holes in the faceplate itself
44
Figure3. 33 Faceplate Lathe Machine
3. Heavy duty lathe - A special type of lathe A lathe is a stationary machine that is used to manufacture work pieces that are
symmetric about an axis of rotation. Heavy duty lathes are a special type of lathe.
Contrary to small and medium sized lathes, heavy duty lathes can process work pieces
weighing up to several tones. Heavy duty lathes can produce products such as shanks,
camshafts and cranks for ship diesel engines, spools for mills, or hydraulic shanks for
powerful linear motors.
Figure3. 34 Heavy duty lathe
45
4. Boring Vertical Turret lathe (BVT)
A vertical turret lathe works much like an engine lathe turned up on end. You can
perform practically all of the typical lathe operations on a vertical turret lathe,
including turning, facing, boring, machining tapers, and cutting internal and external
threads.
Figure3. 35 Boring Vertical Turret lathe
3.3.6 Gear Hobbing Machine Hobbing is a machining process for gear cutting, cutting splines, and
cutting sprockets on hobbing machine, which is a special type of milling. The teeth or
splines are progressively cut into the work piece by a series of cuts made by a cutting
tool called a hob. Compared to other gear forming processes it is relatively
inexpensive but still quite accurate, thus it is used for a broad range of parts and
quantities.
It is the most widely used gear cutting process for creating spur and helical gears.
46
Figure3. 36 Hub Cutter
3.3.7 Horizontal Boring Machine
A horizontal boring machine or horizontal boring mill is a machine
tool which bores holes in a horizontal direction.
Figure3. 37 Horizontal Boring Machine
A horizontal boring machine has its work spindle parallel to the ground and work
table. Typically there are 3 linear axes in which the tool head and part move.
Convention dictates that the main axis that drives the part towards the work spindle is
the Z axis, with a cross-traversing X axis and a vertically traversing Y axis. The work
spindle is referred to as the C axis and, if a rotary table is incorporated, its centre line
is the B axis
47
3.3.8 MILLING MACHINE Milling is the process of machining flat, curved, or irregular surfaces by feeding the
work piece against a rotating cutter containing a number of cutting edges. The usual
Mill consists basically of a motor driven spindle, which mounts and revolves the
milling cutter, and a reciprocating adjustable worktable, which mounts and feeds the
work piece.
Figure3. 38 MILLING MACHINE
Milling machines are basically classified as vertical or horizontal. These machines are also classified as knee-type, ram-type, manufacturing or bed type, and planer-type. Most milling machines have self-contained electric drive motors, coolant systems, variable spindle speeds, and power-operated table feeds
48
Peripheral Milling (Horizontal Milling) vs. Face Milling (Vertical
Milling)
1. Peripheral milling or plain milling:
Cutter axis is parallel to surface being machined
Cutting edges on outside periphery of cutter
2. Face milling
Cutter axis is perpendicular to surface being milled
Cutting edges on both the end and outside periphery of the cutter
Types of Milling
Peripheral Milling
Slab milling
Slotting
Side milling
Straddle milling
Face milling
Conventional face milling
Partial face milling
End milling
Profile milling
Pocket milling
Surface contouring
49
3.3.9 DRILLING MACHINE Drilling machine is one of the most important machine tools in a workshop. It was
designed to produce a cylindrical hole of required diameter and depth on metal work
pieces. Though holes can be made by different machine tools in a shop, drilling
machine is designed specifically to perform the operation of drilling and similar
operations. Drilling can be done easily at a low cost in a shorter period of time in a
drilling machine.
Drilling can be called as the operation of producing a cylindrical hole of required
diameter and depth by removing metal by the rotating edges of a drill. The cutting
tool known as drill is fitted into the spindle of the drilling machine. A mark of
indentation is made at the required location with a centre punch. The rotating drill is
pressed at the location and is fed into the work. The hole can be made up to a required
depth.
Size of a drilling machine
Drilling machines are specified according to their type.
To specify the machine completely the following factors are considered:
The maximum diameter of the drill that it can handle
The size of the largest work piece that can be centered under the spindle
50
Distance between the face of the column and the axis of the spindle
Diameter of the table
Maximum travel of the spindle
Numbers and range of spindle speeds and feeds available
Morse taper number of the drill spindle
Floor space required
Weight of the machine
Power input is also needed to specify the machine completely.
Tools used in a drilling machine
Different tools are used for performing different types of operations. The most
commonly used tools in a drilling machine are
1. Drill
2. Reamer
3. Counter bore
4. Countersink
5. Tap
1. Radial drilling machine
The radial drilling machine is intended for drilling on medium to large and heavy
work pieces. It has a heavy round column mounted on a large base. The column
supports a radial arm, which can be raised or lowered to enable the table to
accommodate work pieces of different heights. The arm, which has the drill head on it,
can be swung around to any position. The drill head can be made to slide on the radial
51
arm. The machine is named so because of this reason. It consists of parts like base,
column, radial arm, drill head and driving mechanism.
Figure3. 39 Radial drilling machine
2. Bench and Column or Pillar type drilling machines
There are two types of machine drill, the bench drill and the pillar drill. The bench
drill is used for drilling holes through materials including a range of woods, plastics
and metals. It is normally bolted to a bench so that it cannot be pushed over and that
larger pieces of material can be drilled safely. The larger version of the machine drill
is called the pillar drill. This has a long column which stands on the floor. This can do
exactly the same work as the bench drill but because of its larger size it is capable of
being used to drill larger pieces of materials and produce larger holes.
52
Figure3. 40 Bench and Column or Pillar type drilling machines
3.3.10 Shaper
A shaper is a machine tool which holds and locates a work piece on a table and
machines or cuts the work piece by feeding it against a reciprocating cutting tool. In
other words, the ram of the shaper moves a single point cutting tool back-and-forth,
and on each forward stroke, the tool removes a chip of metal from the work piece.
The work piece is held in the vise of the shaper or secured to the table of the shaper
with clamps, T-bolts, etc. When horizontal surfaces are being machined, the table
automatically feeds the work to the cutting tool on each return stroke of the ram.
When vertical cuts are being made, the work is fed to the cutting tool on each return
stroke of the ram either manually or automatically. The cutting tool on a shaper can
be set to cut horizontally, on an angle, or vertically.
53
Figure3. 41 Shaper
Types of Shapers
There are three types of shapers:
Crank shapers
Gear shapers
Hydraulic shapers
Crank shapers are most commonly used. A rocker arm, operated by a
crank pin from the main driving gear, gives the ram of the crank shaper a
back-and-forth (reciprocating) motion.
Gear shapers are driven by a gear and rack assembly. Gear shapers have a
reversible electric motor or mechanical mechanism which quickly returns the
ram, in readiness for another cut.
Hydraulic shapers are driven by movement of a piston in an oil-filled
cylinder. Mechanical features on these shapers are the same as those on crank
shapers.
54
3.3.11 Planer
A planer is a type of metalworking machine tool that uses linear relative motion
between the work piece and a single-point cutting tool to machine a linear tool
path. Its cut is analogous to that of a lathe, except that it is linear instead of helical.
A planer is analogous to a shaper, but larger, and with the entire work piece moving
on a table beneath the cutter, instead of the cutter riding a ram that moves above a
stationary work piece. The table is moved back and forth on the bed beneath the
cutting head either by mechanical means, such as a rack and pinion drive or a lead
screw, or by a hydraulic cylinder
Figure3. 42 Planer
Linear planing Helical planing Prevalence of current use
Double-housing planers
Double-housing planers are the most widely used and provide the greatest tool
support rigidity. The major components of a double-housing planer are the bed, table,
housings, arch, cross rail, and heads (side and rail). The bed is the foundation to
55
which the housings are attached. The bed is provided with precision ways over its
entire length and supports the reciprocating table.
The table supports the work piece and reciprocates along the ways of the bed. The
table is slightly less than half the length of the bed and its travel determines the
dimensional capacity of the machine in length of stroke. The housings are rigid box-
type columns placed on each side of the bed and table. They are heavily braced and
ribbed to absorb the large cutting forces encountered in planing. The arch joins the
housings at the top for greater rigidity of construction and also houses the drive
mechanism for tool feeding. The cross rail is a rigid horizontal beam mounted above
and across the table on the vertical ways of the columns. It supports the rail heads and
provides for horizontal feeding of the cutting tools
Figure3. 43 Double-housing planers
3.3.12 GRINDING MACHINES
Grinding is a process of removing materials in the form of ground chips from a work
piece by mechanical action of many small abrasive particles bonded together in a
56
grinding wheel. Each abrasive particle is acting as a small cutting tool. It is a finishing
process employed for producing close dimensional accuracies and smooth surface
finish the work piece. The regulating wheel is having same direction of rotation as the
grinding wheel. The axial movement of the work piece is obtained a longitudinal feed
by tilting the regulating wheel at a slight angle of 1 to 8 degrees relative to grinding
wheel.
Figure3. 44 GRINDING MACHINES
3.3.13 Slotting machine
Slotting machines or slotters are cutting machines designed to machine slots and
grooves into a work piece.
Slotting Machine Operation Slotting machines operate using a mounted blade in conjunction with a movable table
that moves metal back and forth to create cuts and shapes. Shaping machines
generally have a cutting tool that is mounted vertically. Because of this, slotting
machines are many times referred to as vertical shapers. However, sometimes slotters
57
are distinguished as having fixed blades while shapers have adjustable mounts and
slides.
Selecting Slotting Machines The most important considerations when selecting a slotting machine are the stroke
length, spindle orientation, motor power, and slotter features.
Stroke length determines the reach of the ram that holds and propels the cutting
tool. A larger stroke means a farther cut forward and back. Stroke can generally be
set between a range of lengths.
Spindle orientation is what determines the particular type of shaping machine
based on the direction of its stroke (horizontal, vertical, or angled). Slotting
machines generally utilize vertically mounted cutting tools, but can have
horizontal or angled blades fixed to a vertical ram.
Motor power is the amount of power the motor provides to drive the ram and
cutting tool. This is usually measured in horsepower (HP). Larger motors provide
the power to cut bigger sized work pieces requiring deeper strokes at higher
speeds.
Features on slotting machines can also determine its usefulness in various
applications. These include rotary tables, which allow slotters to machine curved
surfaces, and digital automation via computer numerical control (CNC).
A large number of sizing properties may also be important depending on the type of
work pieces being machined. These include ram and throat adjustment lengths, ram
bearing length, table diameter, base plate dimensions, and the space between the head
and table.
58
Figure3. 45 Slotting machine
Industries and Applications Slotting machines are used to cut grooves and slots in shapes and holes while
additionally smoothing the worked surface. They are used in steel rolling mills, paper
mills, power plants, ship building, textile factories, tool rooms, and repair shops.
3.3.14 Overhead cranes Overhead cranes, sometimes also called bridge cranes, are cranes with a hoist
traveling along the bridge between parallel runways. They are designed to meet the
medium to heavy industrial lifting requirements, covering all parts of the
manufacturing process
59
Figure3. 46 Overhead cranes
3.4 ASSEMBLY SHOP
An assembly line is a manufacturing process (most of the time called a progressive
assembly) in which parts (usually interchangeable are added to a product in a
sequential manner to create a finished product much faster than with handcrafting-
type methods.
3.4.1 Important Terms used in Limit System
The following terms used in limit system (or interchangeable system) is important
from the subject point of view:
Nominal size. It is the size of a part specified in the drawing as a matter of
convenience.
Basic size. It is the size of a part to which all limits of variation (i.e. tolerances)
are applied to arrive at final dimensioning of the mating parts. The nominal or
basic size of a part is often the same.
60
Actual size. It is the actual measured dimension of the part. The difference
between the basic size and the actual size should not exceed a certain limit;
otherwise it will interfere with the interchangeability of the mating parts.
Limits of sizes. There are two extreme permissible sizes for a dimension of the
part as shown in Fig.1. The largest permissible size for a dimension of the part is
called upper or high or maximum limit, whereas the smallest size of the part is
known as lower or minimum limit.
Allowance. It is the difference between the basic dimensions of the mating parts.
The allowance may be positive or negative. When the shaft size is less than the
hole size, then the allowance is positive and when the shaft size is greater than the
hole size, then the allowance is negative.
Tolerance. It is the difference between the upper limit and lower limit of a
dimension. In other words, it is the maximum permissible variation in a
dimension. The tolerance may be unilateral or bilateral. When all the tolerance is
allowed on one side of the nominal size, e.g.., then itis said to be unilateral system
61
of tolerance. The unilateral system is mostly used in industries as it permits
changing the tolerance value while still retaining the same allowance or type of fit.
When the tolerance is allowed on both sides of the nominal size, e.g. , then it is said to
be bilateral system of tolerance. In this case + 0.002 is the upper limit and – 0.002 is
the lower limit.
The method of assigning unilateral and bilateral tolerance is shown in Fig.2 (a) and(b)
respectively.
7. Tolerance zone. It is the zone between the maximum and minimum limit size, as
shown in Fig.3.
Figure3. 47 Tolerance Zone
62
Zero line. It is a straight line corresponding to the basic size. The deviations are
measured from this line. The positive and negative deviations are shown above and
below the zero line respectively.
9. Upper deviation. It is the algebraic difference between the maximum size and the
basic size. The upper deviation of a hole is represented by a symbol ES (Ecart
Superior) and of a shaft, it is represented by es.
10. Lower deviation. It is the algebraic difference between the minimum size and the
basic size. The lower deviation of a hole is represented by a symbol EI (Ecart Inferior)
and of a shaft, it is represented by ei.
11. Actual deviation. It is the algebraic difference between an actual size and the
corresponding basic size.
12. Mean deviation. It is the arithmetical mean between the upper and lower
deviations.
13. Fundamental deviation. It is one of the two deviations which is conventionally
chosen todefine the position of the tolerance zone in relation to zero line, as shown in
Fig. 4.
63
3.4.2 Fits:
The degree of tightness or looseness between the two mating parts is known as a fit of
the parts. The nature of fit is characterized by the presence and size of clearance and
interference.
The clearance is the amount by which the actual size of the shaft is less than the
actual size of the mating hole in an assembly as shown in Fig.5 (a). In other words,
the clearance is the difference between the sizes of the hole and the shaft before
assembly. The difference must be positive.
Figure3. 48 Type of fit
64
The interference is the amount by which the actual size of a shaft is larger than the
actual finished size of the mating hole in an assembly as shown in Fig.5 (b). In other
words, the interference is the arithmetical difference between the sizes of the hole and
the shaft, before assembly. The difference must be negative.
Types of Fits
According to Indian standards, the fits are classified into the following three groups :
Clearance fit. In this type of fit, the size limits for mating parts are so selected
that clearance between them always occur, as shown in Fig.5 (a). It may be
noted that in a clearance fit, the tolerance zone of the hole is entirely above the
tolerance zone of the shaft.
In a clearance fit, the difference between the minimum size of the hole and the
maximum size of the shaft is known as minimum clearance whereas the
difference between the maximum size of the hole and minimum size of the
shaft is called maximum clearance as shown in Fig.5 (a).
The clearance fits may be slide fit, easy sliding fit, running fit, slack running
fit and loose running fit.
Interference fit. In this type of fit, the size limits for the mating parts are so
selected that interference between them always occur, as shown in Fig.5 (b). It
may be noted that in an interference fit, the tolerance zone of the hole is
entirely below the tolerance zone of the shaft.
65
In an interference fit, the difference between the maximum size of the hole and
the minimum size of the shaft is known as minimum interference, whereas
the difference between the minimum size of the hole and the maximum size of
the shaft is called maximum interference, as shown in Fig.5 (b).
The interference fits may be shrink fit, heavy drive fit and light drive fit.
3. Transition fit. In this type of fit, the size limits for the mating parts are so
selected that either a clearance or interference may occur depending upon the
actual size of the mating parts, as shown in Fig.5 (c). It may be noted that in a
transition fit, the tolerance zones of hole and shaft overlap. The transition fits
may be force fit, tight fit and push fit.
3.4.3 Basis of Limit System
The following are two bases of limit system:
1. Hole basis system. When the hole is kept as a constant member (i.e. when the lower
deviationof the hole is zero) and different fits are obtained by varying the shaft size,
as shown in Fig. 6 (a),then the limit system is said to be on a hole basis.
2. Shaft basis system. When the shaft is kept as a constant member (i.e. when the
upper deviation of the shaft is zero) and different fits are obtained by varying the hole
size, as shown in Fig. 6 (b),then the limit system is said to be on a shaft basis.
66
Figure3. 49 Basis of limit system
The hole basis and shaft basis system may also be shown as in Fig. 7, with respect to
the zero line
3.5 Tool Room
A toolroom is a room where tools are stored or, in a factory, a space where tools are
made and repaired for use throughout the rest of the factory. In engineering and
manufacturing, tool room activity is everything related to tool-and-die facilities in
contrast to production line activity.
67
3.5.1 Tools and Dies A tool is a precision device for cutting or shaping metals and other materials.
A die is a form used to shape metal in forging and stamping operations. Dies
also include metal molds used in making plastics, ceramics, and composite
materials. A jig is used to hold metal while it is being drilled, bored or
stamped.
3.5.2 Equipment’s use in Tool Room Grinding Machine
Surface Grinding Machine
Internal Grinding Machine
Spline Grinding Machine
Center less Grinding Machine
Universal Cylindrical Grinding Machine
Hub Grinding Machine
Cutter Grinding Machine
Jig Boring Machine
Thread Gearing Machine
Milling Machine
Lathe Machine
Shaper Machine
Boring Machine
Tool Sharping Machine
68
3.6 Heat treatment and TTC (Technical Training Cell)
Heat treatment
Heat Treatment is the controlled heating and cooling of metals to alter their physical
and mechanical properties without changing the product shape.
3.6.1 Heat treatment – the processes
Annealing
Normalizing
Hardening (Surface, Full, Case)
Tempering
Stress releasing
Carburizing (Gas, Pack)
Phosphating
Annealing
Annealing, in metallurgy and materials science, is a heat treatment wherein a material
is altered, causing changes in its properties such as strength and hardness. It
is a process that produces conditions by heating to above the re-
crystallization temperature and maintaining a suitable temperature, and
then cooling. Annealing is used to induce ductility, soften material,
relieve internal stresses, refine the structure by making it homogeneous, and
improve cold working properties.
69
Figure3. 50 Annealing
Normalizing Annealing, in metallurgy and materials science, is a heat treatment wherein a material
is altered, causing changes in its properties such as strength and hardness. It
is a process that produces conditions by heating to above the re-
crystallization temperature and maintaining a suitable temperature, and
then cooling. Annealing is used to induce ductility, soften material,
relieve internal stresses, refine the structure by making it homogeneous,
and improve cold working properties. In the cases of copper, steel, silver, and
brass this process is performed by substantially heating the material (generally until
glowing) for a while and allowing it to cool slowly. In this fashion the metal is
softened and prepared for further work such as shaping, stamping, or forming.
Figure3. 51 Normalizing
70
Hardening
(a) Flame hardening A high intensity oxy-acetylene flame is applied to the selective region. The
temperature is raised high. The "right" temperature is determined by the operator
based on experience by watching the color of the steel. The overall heat
transfer is limited by the torch and thus the interior never reaches the high
temperature. The heated region is quenched to achieve the desired
hardness. Tempering can be done to eliminate brittleness.
Figure3. 52 Hardening
(b) Induction hardening In Induction hardening, the steel part is placed inside an electrical coil
which has alternating current through it. This energizes the steel part and heats it
up. Depending on the frequency and amperage, the rate of heating as well as
the depth of heating can be controlled. Hence, this is well suited for surface
heat treatment. The Induction and flame hardening processes protect areas exposed to
excessive wear. Items that we induction harden include Spur Gears and Spur Pinions
,Helical Gears and Helical Pinions, Sprockets, Internal Gears, Bevel Gears, Shafts and
71
Pins, Rails and Racks, Wheels and Rollers Sheave Wheels, Links, Axle Boxes and
Bushes.
Figure3. 53 Induction hardening
4. Tempering
Tempering is a heat treatment technique for metals, alloys and glass. In steels,
tempering is done to "toughen" the metal by transforming brittle marten site into
bainite or a combination of ferrite and cementite. Precipitation hardening
alloys, like many grades of aluminum and super alloys, are
tempered to precipitate inter metallic particles which strengthen the metal.
Tempering is ac co mp l i s hed b y a c on t ro l l ed r ehe a t i n g o f t he wo rk
p i ec e t o a t em pe ra tu re be l o w i t s l o we r critical temperature.
T he b r i t t l e ma r t e n s i t e be co me s s t r o n g a nd du c t i l e a f t e r i t i s
t em pe red . C a rb o n a t om s we re trapped in the austenite when it was rapidly
cooled, typically by oil or water quenching, forming the marten site. The marten site
becomes strong after being tempered because when reheated, the microstructure can
rearrange and the carbon atoms can diffuse out of the distorted BCT structure. After
the carbon diffuses, the result is nearly pure ferrite.
72
5. Stress releasing
Stress releasing is used to reduce residual stresses in large castings,
welded parts and cold-formed parts. Such parts tend to have stresses due
to thermal cycling or work hardening. Parts are heated to temperatures of up to
600 - 650 ºC (1112 - 1202 ºF), and held for an extended time (about 1 hour or more)
and then slowly cooled in still air.
6. Carburizing
Carburizing, also known as carburization, is a heat treatment process in
which iron or steel is heated in the presence of another material (but below the
metal's melting point) which liberates carbon as it decomposes. The outer
surface or case will have higher carbon content than the o r i g i na l
m a t e r i a l . W he n t he i ro n o r s t e e l i s c oo l e d ra p i d l y b y q uen c h i ng ,
t he h i gh e r ca rb o n content on the outer surface becomes hard, while the core
remains soft and tough. This manufacturing process can be characterized by
the following key points: It is applied to low-carbon work pieces; work
pieces are in contact with a high-carbon gas, liquid or solid; it produces a
hard work piece surface; work piece cores largely retain their toughness and ductility
and it produces case hardness depths of up to 0.25 inches (6.4 mm).
Figure3. 54 Carburizing
73
7. Phosphating
Phosphate coatings are used on steel parts for corrosion resistance, lubricity, or as a
foundation for subsequent coatings or painting. It serves as a conversion coating in
which a dilute solution of phosphoric acid and phosphate salts is applied via spraying
or immersion chemically reacts with the surface of the part being coated to
form a layer of insoluble, crystalline phosphates. Phosphate conversion
coatings can also be used on aluminum, zinc, cadmium, silver and tin. The main types
of phosphate coatings are manganese, iron and zinc. Zinc phosphates are used for
rust proofing (P&O), a lubricant base layer, and as a paint/coating base and can
also be applied by immersion or spraying.
Figure3. 55 Phosphatin
74
3.7 TTC (TECHNICAL TRAINING CELL)
We study and work on CNC LATHE MACHINE and machined a job on CNC lathe.
CNC LATHE MACHINE PROGRAM
O1130 (Program Number In Machine)
M03 S700
G00 x51.0 Z0.0 T0101
G71 42.0 R1.0
G71 P10 Q20 40.01 W0.01 F100
N10 G01 X10.0
Z15.0
X20.0
Z25.0
X30
Z33.0
X50.0 Z42.0
Z67.0
N20 X51.0
G00 X200.0 Z300.0
75
M30%
U2.0: Depth of cut in x-axis
M03: Clockwise
M04: Counter-clockwise
M05: Spindle stop
R: Retrack
P 10: 1st block
Q 20: 2nd block
U: Finishing allowance in x-axis
W: Finishing allowance in z-axis
F: Cutting feed.
G71:Turning cycle
76
3.8 CTC Fabrication shop
CTC stands for Central Technical Cell and is a drawing and planning section of
fabrication shop, in each of these sections
different drawings are analyzed and then sent to the different segments of fabrication
shop depending upon the job and capacity of the shop. The main jobs of CTC
fabrication are:
Job feeding to shop
Planning
Material check
Observation from manufacturing till sale
77
3.9 Fabrication shop Metal fabrication is the building of metal structures by cutting, bending, and
assembling processes
Cutting is done by sawing, shearing, or chiseling
Bending is done by hammering (manual or powered)
Assembling (joining of the pieces) is done by welding
Basically Fabrication Shop is divided into four sections:
Heavy bay section
Medium bay section
Small bay section
Marking and layout section
List of apparatus and machines
The machines in the fabrication shop and their capacities are given below:
1. Small bay
2.5 ton press
5 ton bending machine
2. Medium bay
Shaft cutting circular saw
o Cutting diameter1350mm
78
Shaft welding machine
o Height of beam450mm
3. Heavy bay
3000 ton press
1000 ton rolling machine
50 ton capacity cranes
Marketing layout and cutting section
Photo cell cutting machine
o Electromagnetic or paper templates are used
CNC cutting machine
o A German CNC cutting machine is used for cutting accurate and
complex parts
Plasma arc cutting machine for non ferrous metals
Semi automatic cutting machine
o Oxygen and natural gas are used for cutting
Mechanical cutting machine (shearing machine)
Parallel cutting machine
Trennjaeger machine
Nine rollers
Straightening machine
79
3.9.1 Welding Mainly welding is done in all bays of fabrication shop. The type
of welding used in fabrication shop is as follows:
1. Gas tungsten arc welding (GTAW)
Gas tungsten arc welding (GTAW), also known as tungsten inert gas (TIG) welding,
is an arc welding process that uses a non-consumable tungsten electrode to produce
the weld. The weld area is protected from atmospheric contamination by an inert
shielding gas (argon or helium), and a filler metal is normally used, though some
welds, known as autogenous welds, do not require it. A constant-current welding
power supply produces electrical energy, which is conducted across the arc through a
column of highly ionized gas and metal vapors known as plasma.
GTAW is most commonly used to weld thin sections of stainless steel and non-
ferrous metals such as aluminum, magnesium, and copper alloys
Figure3. 56 Gas tungsten arc welding
80
2. MIG Welding (GMAW)
Gas metal arc welding (GMAW), sometimes referred to by its subtypes metal inert
gas (MIG) welding or metal active gas (MAG)welding, is a welding process in
which an electric arc forms between a consumable wire electrode and the work piece
metal(s), which heats the work piece metal(s), causing them to melt, and join.
Figure3. 57 MIG Welding
3. Submerged arc welding (SAW)
The process requires a continuously fed consumable solid or tubular (metal cored)
electrode. The molten weld and the arc zone are protected from atmospheric
contamination by being "submerged" under a blanket of granular fusible flux
consisting of lime, silica, manganese oxide, calcium fluoride, and other compounds.
When molten, the flux becomes conductive, and provides a current path between the
electrode and the work. This thick layer of flux completely covers the molten metal
81
thus preventing spatter and sparks as well as suppressing the intense ultraviolet
radiation and fumes that are a part of the shielded metal arc welding (SMAW)
process.
SAW is normally operated in the automatic or mechanized mode, however, semi-
automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are
available
Figure3. 58 Submerged arc welding
4. SMAW Welding
Shielded metal arc welding (SMAW), also known as manual metal arc
welding (MMA or MMAW), flux shielded arc welding[1] or informally as stick
welding, is a manual arc welding process that uses a consumable electrode covered
with a flux to lay the weld.
82
An electric current, in the form of either alternating current or direct current from
a welding power supply, is used to form an electric between the electrode and
the metals to be joined. The work piece and the electrode melts forming the weld pool
that cools to form a joint. As the weld is laid, the flux coating of the electrode
disintegrates, giving off vapors that serve as shielding and providing a layer of slag,
both of which protect the weld area from atmospheric contamination.
Figure3. 59 SMAW Welding
83
Chapter4
Foundry & Forge Works
4.1 Pattern Shop
4.2 Steel & Cast iron Foundry
4.3 Forging Shop
84
4.1 PATTERN SHOP
The purpose of pattern shop is to make wooden or metallic components for casting
process.
Pattern
“PATTERN MAKING IS THE ART OF MAKING AN ORIGINAL PATTERN OR FORM
WHICH WILL BEUSED TO MAKE A MOLD IN WHICH MOLTEN MATERIAL
WILL BE POURED DURING CASTINGPROCESS.”
Figure4. 1 pattern
Pattern used in sand casting may be made of wood, metallic, plastic or other materials.
Woods chosen for this purpose should be easy enough to work and shape, straight,
and evenly grained, sufficiently dry and most importantly, dimensionally stable.
85
4.1.1 Types of Pattern One piece or solid pattern
Two piece or split pattern
Three piece pattern
Loose piece pattern
Self core pattern
Sweep pattern
Skeleton pattern
Match plate pattern
Connecting pattern
Master pattern
Wooden patterns
Wooden patterns are used when amount of castings are low and we need rough finishing. They are not
expensive.
Figure4. 2 Wood pattern
86
Metallic patterns
Metallic patterns are used when amount of castings are very large and we need fine surface finish. These
are very expensive. Cost is compensated by the no. of castings.
Figure4. 3 Metallic patterns
Material Used In HMC for Pattern Making
Deodar Wood
Brass (used for metallic pattern)
Aluminum (used for metallic pattern)
Pattern material is depending upon their usage. If usage is greater and continuously
repeated then it is made of metallic and expensive wood such as sheeshum etc.
Core Print
A projection made in the pattern is called core print .It is used to form a core seat in
the mold. The core is correctly seated in this seat.
87
4.1.2 Types of Core Prints Top print
Bottom print
Side print
Tail print
Hang print
Balancing print
MACHINES IN PATTERN SHOP:-
Band saw.
Joint planner.
88
Thickness planner.
Disc and spindle sander.
Wooden lathe machine.
Wooden milling machine.
4.1.3 PATTERN ALLOWNCES Shrinkage Allowance
Solid shrinkage is the reduction in volume caused when metal loses temperature in
solid state. A shrinkage allowance for metal casting is something that must be figured
into a design from the very beginning. As the molten metal cools and solidifies it
will begin to contract. This means that although the molten metal completely filled up
a mold, by the time the casting was cold, the casting is smaller than the mold. What
this mean is that a pattern must be made larger than the design drawing. The
difference between the size or dimensions of the desired casting and the size of the
pattern used to create the mold is called a shrinkage allowance. The shrinkage
allowance for metal casting varies by the type of metal. It takes experience in metal
casting to be able to accurately judge the proper shrinkage allowance to be built into a
pattern. The shrinkage allowance for metal casting is linear meaning that these
allowances apply in every direction. Shrinkage allowance for steel = 1.8%Shrinkage
allowance for cast iron = 0.8%
Machining Allowance
Machining allowance is a small amount of material which is added to a pattern
in areas where it will be machined. For inside structure the machining allowance is
negative and for outside it is positive.
89
Draft Allowance
Draft allowance is a small amount of taper made in a pattern which will allow it more
easily removed from the mold.
Shake allowance: Before withdrawal from the sand mold, the pattern is rapped all
around the vertical faces to enlarge the mold cavity slightly which facilitates its
removal. Since it enlarges the final casting made, it is desirable that the original
pattern dimensions should be reduced to account for this increase.
4.2 CAST IRON & STEEL FOUNDARY
INTRODUCTION TO CASTING:
In the casting processes, a material is first melted, heated to proper temperature, and
sometimes treated to modify its chemical composition. The molten materials then
poured into a cavity or mold that holds it in the desired shape during cool-down and
solidification. In a single step, simple or complex shapes can be made from any
material that can be melted. By proper design and process control, the resistance to
working stresses can be optimized and a pleasing appearance can be produced.
Cast parts range in size from a fraction of a centimeter and a fraction of a gram (such
as the individual teeth on a zipper) to over 10 meters and many tons (as in the huge
propellers and stern frames of ocean liners). Moreover, the casting processes have
distinct advantages when the production involves complex shapes parts having hollow
sections or internal cavities, parts that contain irregular curved surfaces (except those
90
can be made from thin sheet metal), very large parts, or parts made from metals that a
difficult machine.
It is almost impossible to design part that cannot be cast by one or more of
commercial casting processes. However, as with all manufacturing techniques, the be
results and lowest cost are only achieved if the designer understands the various
options and tailors the design to use the most appropriate process m the most efficient
manner. The variety of casting processes use different mold materials (sand, metal, or
various ceramics) and pouring methods (gravity, vacuum, low pressure, or high
pressure). All share the requirement that the material should solidify in a manner that
will maximize the properties and avoid the formation of defects, such as shrinkage
voids, gas, porosity, and trapped inclusions.
4.2.1 CAST IRON & STEEL FOUNDARY Basic Requirements of Casting Processes
Six Basic requirements are associated with most casting processes.
A mold cavity, Having the desired shape and size, must be produced with due
allowance for shrinkage of the solidifying material. Any geometrical feature
desired in the finished casting must exist in the cavity. Consequently, the mold
material must be able to reproduce the desired detail and also have a refractory
character so that it will not contaminate the molten material that it will
contain.
A melting process must be capable of providing molten material not only at
the proper temperature, but also in the desired quantity, with acceptable
quality, and within a reasonable cost.
91
A pouring technique must be devised to introduce the molten metal into them
old. Provision should be made for the escape of all air or gases present in the
cavity prior to pouring, as well as those generated by the introduction of the
hot metal. The molten material is then free to fill the cavity, producing a high-
quality casting that is fully dense and free of defects.
The solidification process should be properly designed and controlled.
Castings should be designed so that solidification and solidification shrinkage
can occur without producing internal porosity or voids. In addition, the molds
should not provide excessive restraint to the shrinkage that accompanies
cooling. If they do, the casting may crack when it is still hot and its strength is
low.
It must be possible to remove the casting from the mold (i.e., Mold
removal).With single-use molds that are broken apart and destroyed after each
casting, there is no serious difficulty. With multiple-use molds, however, the
removal of a complex- shaped casting may present a major design problem.
After the casting is removed from the mold, various Cleaning, finishing, and
inspection Operations may be required. Extraneous material is usually
attached where the metal entered the cavity, excess material may be present
along mold parting lines, and mold material often adheres to the casting
surface. All of these must be removed from the finished casting.
92
4.2.2 Sand Casting:
Sand casting, the most widely used casting process, utilizes expendable sand molds to
form complex metal parts that can be made of nearly any alloy. Because the sand
mold must be destroyed in order to remove the part, called the casting, sand casting
typically has a low production rate. The sand casting process involves the use of a
furnace, metal, pattern, and sand mold. The metal is melted in the furnace and then
ladled and poured into the cavity of the sand mold, which is formed by the pattern.
The sand mold separates along a parting line and the solidified casting can be
removed. The steps in this process are described in greater detail in the next section.
Sand casting is used to produce a wide variety of metal components with complex
geometries. These parts can vary greatly in size and weight, ranging from a couple
ounces to several tons. Some smaller sand cast parts include components as gears,
pulleys, crankshafts, connecting rods, and propellers. Larger applications include
housings for large equipment and heavy machine bases. Sand casting is also common
in producing automobile components, such as engine blocks, engine manifolds,
cylinder heads, and transmission cases.
4.2.3 Foundry Process:
Foundries produce castings that are close to the final product shape, i.e., “near-net
shape “components. Castings are produced by pouring molten metal into moulds, with
cores used to create hollow internal sections. After the metal has cooled sufficiently,
the casting is separated from the mould and undergoes cleaning and finishing
techniques as appropriate
93
The production process involves a number of steps as shown
Sand Casting Processes:
Sand molding systems use sand as a refractory material and a binder that maintains
the shape of the mould during pouring. A wide range of sand/binder systems are used.
Green (wet) sand systems, the most common sand system, use bentonite clay as the
binder, which typically makes up between 4% and 10% of the sand mixture. Water,
which makes up around 2–4% of the sand mixture, activates the binder. Carbonaceous
material such as charcoal (2–10% of total volume) is also added to the mixture to
provide a reducing environment. This stops the metal from oxidizing during the
pouring process. Sand typically comprises the remaining 85–95% of the total mixture.
94
4.2.4 To carry out the sand molding process:
1. Bellow: A bellow is used to blow loose sand particles from the pattern and the
mold cavity.
Figure4. 4 Bellow
2. Lifter or cleaner: It lifts dirt or loose sand from the mold. It is used for repairing
and finishing the sand mold cavity.
3. Heart & square: It is employed for finishing the mould cavity.
4. Rammer: It is used for ramming the sand in molds.
Figure4. 5 Rammer
5. Floor rammer: It is larger in size as compared to hand rammer. It is used for floor
molding.
6. Hand riddle: It consists of wire mesh fitted into a circular wooden frame. It is used
for cleaning, removing foreign matter from sand.
95
Figure4. 6 Hand riddle
7. Sprue pin: It is tapered wooden rod which is placed in the cope to make sprue
cavity.
8. Trowels: Trowels used to finish flat surfaces of the mould, cut in gates, make joints
or repair mold.
Figure4. 7 Trowel
9. Smoothers and corner slicers: they are employed to repair and finish corners,
edges, round and flat surfaces.
10. Gate cutter: it is a shaped piece of sheet metal. It is used to cut the gate.
11. Shovel: Shovel used to transfer molding sand from store to place of use. Also
used to mix and temper the molding sand.
Figure4. 8 Shovel
96
12. Flask: It has two parts, upper part is known as cope and the lower part is known
as drag.
Figure4. 9 Flask
4.2.5 Procedure of Sand Casting: 1. Pattern Making
Pattern making is the first stage for developing a new casting. The pattern, or replica
of the finished piece, is typically constructed from wood but may also be made of
metal, plastic, plaster or other suitable materials. These patterns are permanent so can
be used to form a number of moulds. Pattern making is a highly skilled and precise
process that is critical to the quality of the final product.
2. Mould Making and Core Making:
The mould is formed in a mould box (flask), which is typically constructed in two
halves to assist in removing the pattern. Sand moulds are temporary so a new mould
must be formed for each individual casting. A cross-section of a typical two-part sand
mould.
4.2.6 Advantages of Sand Casting:
Use is widespread; technology well developed.
Materials are inexpensive, capable of holding detail and resist deformation
when heated.
97
Process is suitable for both ferrous and non-ferrous metal castings.
Handles a more diverse range of products than any other casting method.
Produces both small precision castings and large castings of up to 1 tone.
Can achieve very close tolerances if uniform compaction is achieved.
Mould preparation time is relatively short in comparison to many other
processes.
The relative simplicity of the process makes it ideally suited to mechanization.
High levels of sand reuse are achievable.
Limitations of Sand Casting:
Typically limited to one or a small number of moulds per box..
Sand: metal ratio is relatively high.
High level of waste is typically generated, particularly sand, bag house dust
and spent shot.
4.2.7 Safety Precautions:
The methods and materials involved in any form of metal casting operation are
very hazardous. Educate yourself on the proper safety precautions before
attempting any metal casting.
Never put water on a metal fire. This can cause a huge explosion!
Have a dry pile of sand and a shovel ready to put out fires or to control metal
spills.
98
Have a sand bed under all areas. The sand bed should be at least 3 inches thick.
This will help in containing metal spills and will help protect flooring.
Never pour over wet ground. Remember, even trace amount of moisture can cause
explosions.
Molten metal spilled on concrete will cause the concrete to explode. Use a thick
sand bed over concrete.
Always use clean metal as feedstock. Combustion residues from some lubricants
and paints can be very toxic.
Always operate in a well-ventilated area. Fumes and dusts from combustion and
other foundry chemicals, processes and metals can be toxic.
Use a niosh rated dusk mask. Dusts from sand, parting dusts and chemicals can be
hazardous or cancer causing. Protect your lungs!
Always use safety glasses. Even minor mishaps can cause blindness.
Never use a crucible that has been damaged or dropped. It's just not worth the risk.
Imagine what would happen if a white-hot crucible of brass crumbled as you were
carrying it!
Always charge crucibles when cold. Adding metal to a hot crucible is really
dangerous. If there is moisture on the metal, even just a haze, the metal can cause
the entire contents of the crucible to explode.
Spilled molten metal can travel for a great distance. Operate in a clear work area.
Think about what you are doing at all times. Focus on the job at hand and the next
step. Have all moves planned and rehearsed prior to any operation.
99
4.3 Forging Shop In HMC there are two forging shop that differs in capacity and type of job.
They are also facilitated with heat treatment processes.
4.3.1 Forging shop I In this shop die forging is done.
Die forging:
In this type of forging method specific dies are used to produce the
specific job for this allowance is very low.
Requirements:
For die forging we need:
Furnace
Hammers
In HMC forging shop 1 has following facilities:
150kg hammering machine
300kg hammering machine
750kg hammering machine
800 ton hydraulic press with 3 ton manipulator
25 to counter blow
Trimming press
Crew presser
63 ton power press
400 ton press
1250 ton press
Swelling crane of 1 ton capacity
100
4.3.2 Forging shop II In this shop free forging is done. Free forging is method of producing jobs without
using dies. In free forging large allowance is present.
HMC have following facilities in this shop:
1 ton hammer
2 ton hammer
3 ton hammer
4.3.3 Forge It is the ability of the material to undergo deformation under compression without
rapture. Any material or alloy which can be brought to plastic stage through
heating can be forged the extent to which the material can be forged is governed
by its compositions as well as temperature of the forging. Selection of the forging
material depend upon certain mechanical prosperities inherent in the material like
strength, malleability, resistance to fatigue , durability, shock or bending
machineability .
Some forgeable materials are listed below:
Pure aluminum
Pure magnesium
Pure copper
Aluminum alloys
Magnesium alloys
101
Copper alloys
Carbon and low alloy steels
Stainless steel
Nickel alloys
Metal forging
Is a metal forming process that involves applying compressive forces to a work piece
to deform it, and create a desired geometric change to the material.
The forging process is very important in industrial metal manufacture, particularly in
the extensive iron and steel manufacturing industry.
A steel forge is often a source of great output and productivity. Work stock is input to
the forge, it may be rolled, it may also come directly from cast ingots or continuous
castings. The forge will then manufacture steel forgings of desired geometry and
specific material properties. These material properties are often greatly improved.
Hot Die vs. Cold Die Forging
Hot forging is done at a high temperature, which makes metal easier to shape and
less likely to fracture. Most metal forging operations are carried out hot, due to the
need to produce large amounts of plastic deformation in the part, and the advantage of
an increased ductility and reduced strength of the work material.
Figure4. 10 Hot Die
102
Cold forging is done at room temperature or near room temperature. Cold
die forging manufacture, while requiring higher forces, will also produce greater
surface finish and dimensional accuracy than hot die forging. Some specific metal
forging processes are always performed cold, such as coining.
Figure4. 11 Cold die
Warm forging is do ne a t in te rm e d ia te t e mp e ra t u re b e t wee n ro o m
t em pe ra t u r e an d h o t f o rg in g t e mpe ra t u r es .
Forged parts can range in weight from less than a kilogram to 170 metric
tons. Forged parts usually require further processing to achieve a finished part
FUNCTIONS OF FORGE SHOP
Production of large and medium size forgings.
Mostly forged parts include railway axles, draw hooks, screw couplings,
cement and sugar plant parts, boiler components, road rollers parts, cranes and
drop tank equipments.
Its annual production is 4500 tons.
Forging Equipment
Hammer Forging
103
A forging method in which the part is distorted by recurrent blows using
a forging hammer, between impression and flat dies. This procedure is also called drop forging
Figure4. 12 Hammer Forging
150kg pneumatic hammer
400kg pneumatic hammer
750kg pneumatic hammer
Forging Machine:
A forging machine includes an anvil mass and a ram block, to be released and struck
against it, between which forging is carried out. The machine comprises of a damping
mass, which experiences the blow and moves in a large amplitude of motion in
comparison with the amplitude of motion of the anvil mass, to damp the blows
conducted from the anvil mass to the stationary foundation of the machine.
Shot blasting machine
104
Pedestal grinder
Quenching tanks_____ 2 oil and water (5m* 3m* 5m each)
Hydraulic Forging Press:
It consists of the press, the hydraulic intensifier, and the auxiliary water tank. A piece
of work is compressed between the dies. Numerous shapes of dies may be used. The
press head is forced down by hydraulic pressure on the ram in the cylinder, and is
lifted by steam pressure under the two pistons in the cylinders. The vertical motion of
the press head is directed by the four columns which hold the press firmly against
distortion. Water pressure is exerted through the pipe from the steam intensifier.
Steam admitted under the piston imparts the pressure to the water.
800 ton drawdown type press along with pump, accumulator station
and forging manipulator.
Figure4. 13 Hydraulic Forging Press:
105
Manipulator
When maximum flexibility in transport and handling capabilities during the forging
process is important a Mobile Forging Manipulator is your first choice.
Figure4. 14 Manipulator
DIE FORGING PRESSES:
60 ton power press
160 ton friction press
400 ton power press
1250 ton friction press.
CRANES:
1 ton stationary stewing crane
5 ton quenching overhead crane
12.5 ton overhead crane
106
20.5 ton forging crane
Figure4. 15 CRANES
FURNACES
Heating furnaces ________ 10
4.84m* 2.08m* 1.5m
Max temp 1300 degree Celsius
Heat treatment furnace ________ 5
15m* 4m* 6m
Max temp 1050 degree Celsius
Figure4. 16 FURNACES
107
108
Chapter5
Quality Assurance & Control
5.1 Non Destructive Testing (NDT) Lab
5.2 Material Testing Laboratory
5.3 Inspection
5.4 ISO 900
109
5.1 Non Destructive Testing Lab (NDT Lab)
Non destructive test is used to identify the defects in welding joints in the NDT lab of
HMC.
Non destructive examination facilities are:
X-ray radiography
Gamma ray radiography
Ultrasonic
Magnetic particle
Liquid penetrate
Eddy current
Spectroscopy
5.1.1 Radiography Techniques Following Radiography techniques are possible, but only three type of
radiography are used mostly X-ray, ultrasonic, and gamma ray radiography
because other radiography is expensive.
Figure5. 1 Radiography Techniques
110
A list of available radiographic methods is given below:
X-ray Radiography
Gamma Ray Radiography
Neutron Radiography
Proton Radiography
X-ero Radiography
Fluoroscopy
Micro Radiography
Flash Radiography
Auto Radiography
Electron transmit Radiography
NDT methods application and limitation
1. Radiography testing method
Radiography is the most universally used NDT method for detection of gas
porosity in the weldments.
The radiography image of a “Round Porosity” will appear as oval shaped spots
with smooth edges, while “elongated porosity” will appear as oval
shaped spots with major axis. Sometimes several time longer then minor
axis.
Foreign material such as loose scale, flux or splatter will affect validity of test
results.
111
1. Ultrasonic Testing method
Ultrasonic testing equipments are highly sensitive, capable of detecting micros
eparations
Surface finishing and grain size will affect the validity of the test
Figure5. 2 Ultrasonic Testing Method
2. Eddy current testing method
Normally confined to thin wall welded pipes and tube
Penetration restricts testing to a depth of more than one quarter inch
Figure5. 3 Eddy current testing method
3. Liquid penetrate testing method
Normally confined to in processes control of ferrous and non ferrous welds
112
Liquid penetrant testing is like magnetic particle is restricted to surface
evaluation
Extreme condition must be exercised to prevent any cleaning
material
Figure5. 4 Liquid penetrate testing method
4. Magnetic particle testing method
Normally used to detect gas porosity .Only surface porosity would be evident.
Near surface porosity would not be clearly defined, since indications are neither
strong nor pronounced
Figure5. 5 Magnetic particle testing method
113
5.2 MATERIAL TESTING LABORATORY
The objective of material testing laboratory is to check the chemical
composition of different alloys of iron, copper as well as other nonmetallic
elements. The facility contains the following laboratories:
Quick response section.
Mechanical testing section
Heat treatment section
Microscope section
Wet test laboratory
(a) QUICK RESPONSE SECTION
The quick response section is situated near the steel foundry and it helps the foundry
men to melt different alloys in exact element ratios to get specific allows. It
has the facility to inspect the molten metal from the furnace at intervals
and provide the feedback within a few minutes.
The facility has the following apparatus:
Emission spectrometer.
Spectrophotometer.
Carbon furnace.
Titration apparatus.
114
EMISSION SPECTROMETER
This instrument vaporizes the metal by producing an electric spark and then analyses t
he spectrum of the resulting vapors to identify the percentage of 26 different metals in
the given alloy. It has the capability to detect both iron based and copper based metals.
The elements that are detected by it include the following: Carbon, silicon, manganese,
phosphorus, sulphur, chromium, molybdenum, aluminum, copper, cobalt, titanium,
vanadium, tungsten, lead, boron, tin, zinc, arsenic, bismuth, calcium, cesium,
zirconium, and iron.
(b) MECHANICAL TESTING SECTION
This testing section includes the following machines:
Universal testing machine
Impact test machine
Brinnel hardness testing machine
Rockwell hardness tester and Vickers
Wear testing machine
(c) WET TEST LABORATORY
In the wet test laboratory, we use the element analysis to measure the moisture
contents in any material or a specimen or element.
115
5.3 Quality Control Inspection
Quality control emphasizes testing of products to uncover defects and reporting to
management who make the decision to allow or deny product release, whereas quality
assurance attempts to improve and stabilize production (and associated processes) to
avoid, or at least minimize, issues which led to the defect(s) in the first place.
Inspection
An inspection is, most generally, an organized examination or formal evaluation
exercise. In engineering activities inspection involves the measurements, tests,
and gauges applied to certain characteristics in regard to an object or activity. The
results are usually compared to specified requirements and standards for determining
whether the item or activity is in line with these targets, often with a Standard
Inspection Procedure in place to ensure consistent checking. Inspections are usually
non-destructive.
Inspections may be a visual inspection or involve sensing technologies such
as ultrasonic testing, accomplished with a direct physical presence or remotely such as
a remote visual inspection, and manually or automatically such as an automated
optical inspection.
5.3.1 Inspection tool mostly used are: Inside micrometer
Outside micrometer
Venire caliper
Bevel protector etc
116
(a) VERNIER CALIPER
Figure5. 6 VERNIER CALIPER:
The Vernier Caliper is a precision instrument that can be used to measure internal and
external diameters extremely accurately.
Measurements are interpreted from the scale by the user. This is more difficult than
using a digital vernier caliper which has an LCD digital display on which the reading
appears.
The manual version has both an imperial and metric scale.
Manually operated vernier calipers can still be bought and remain popular because
they are much cheaper than the digital version.
Also, the digital version requires a small battery whereas the manual version does not
need any power source
117
(b) MICROMETER:
Figure5. 7 MICROMETER
A Micrometer is a precision measuring instrument, used by Engineers. The
Micrometer is capable of measuring one millionth of a meter i.e. 0.001 mm.
In Micrometer each revolution of the Rachet moves the spindle face 0.05 mm towards
the anvil face.
The object to be measured is placed between the anvil face and the spindle face.
The rachet is turned clockwise until the object is trapped between these two surfaces
and the rachet makes a clicking noise.
This means that the rachet cannot be tighten anymore and the measurement can be
read
118
5.4 ISO 9001
As an ISO 9001 certified organization you will have implemented Quality
Management System requirements for all areas of the business, including:
Facilities
People
Training
Services
Equipment
5.4.1 Benefits of ISO 9001
ISO 9001 Certification will provide maximum benefit to your organization if it
approaches ISO 9001 implementation in a practical way. This will ensure that the
Quality Management Systems that are adopted work to improve the business and are
not just a set of procedures that your employees will find hard to manage.
By adopting an approach that starts out to implement more efficient working practices
and focuses on the business objectives of the organization, you will achieve a system
that will help and support your staff, and improve your levels of customer satisfaction.
Whether you use an external assessor or allocate an internal resource to carry out the
initial assessments, you will need to ensure that they have buy-in from senior
management, so that all areas of the organization are aware of the importance of
the ISO 9001 Certification process.
ISO 9001 Certification is not just suitable for large organizations but also small
businesses that will benefit from adopting efficient Quality Management Systems that
119
will save time and cost, improve efficiency and ultimately improve customer
relationships.
5.4.2 Some of the benefits to your organization:
Provides senior management with an efficient management process
Sets out areas of responsibility across the organization
Mandatory if you want to tender for some public sector work
Communicates a positive message to staff and customers
Identifies and encourages more efficient and time saving processes
Highlights deficiencies
Reduces your costs
Provides continuous assessment and improvement
Marketing opportunities
5.4.3 Some of the benefits to your customers:
Improved quality and service
Delivery on time
Right first time attitude
Fewer returned products and complaints
Independent audit demonstrates commitment to quality
5.4.4 ISO 9001 Assessment Process The ISO 9001 standard covers every part of your business management systems. It is
therefore vital to appoint an assessor who has the experience to implement ISO 9001
certification across all areas of your organization.
120
The assessor can be appointed internally from senior management with the relevant
authority and expertise, or externally from an accredited certification body. The
reality is usually a combination of both.
This will give you the most effective quality management system that will work for
your business. It will provide a system that can be constantly monitored and improved
upon by your internal team. In addition, an external assessor will bring in expertise
and best practice from a wider industry perspective. This will help to ensure that when
the audit is done, your management systems comply with the requirements of
ISO9001.
ACS Registrars have UKAS Accreditation, so before you start contact us to find out
more.
5.4.5 Other things you will need to consider
Gain support from employees throughout the organization
Allow 3 to 6 months to achieve certification
Gather information on current systems
Compare and improve current systems in line with ISO 9001 requirements
Develop and review your quality manual and ensure it meets the
requirements of ISO 9001
Identify non compliance areas
Set up a monitoring schedule
121
Review any training requirements for employees
Do a company management review and internal audits
Set a date for your first audit
5.4.6 ISO 9001 Regular Auditing Procedure
Once you have successfully negotiated your first audit, it is important to continue to
monitor the process and improve your systems.
Annual surveillance visits need to be arranged; this will help to ensure that the re-
certification audit carried out every 3 years is a formality rather than a major process
overhaul.
5.4.7 During the audit you will be assessed on:
Documentation control
Records being kept
Staff and management conformance to the system
How the system is working in each area of the organization
Staff training necessary to meet the requirements
122
Recommendations
I would like to give some recommendations to improve the quality of work and
save time along the health of the workers because during our visit i observed that
the workers are not playing with their own lives which are a great loss of man power.
To eradicate it we recommend following things:
Safety should be made necessary for each and every one especially for
the fabrication shop
There should be check and balance of these safety steps
Trained labor must have junior or fresh labor because in the future they can
take their seats.
Environment should be made clean and healthy by planting plants and keeping
the surface clean
To increase the rate of work the repeated jobs should be given to that person
who had worked on it but this should be made necessary for that person that
he will convey his knowledge to his subordinates.
123
124
References
[1] https://www.asme.org
[2] mechanicalview.blogspot.com
[3] Textbook of Machine design (S.I Unit) by R.S. KHURMI & J.K. GUPTA
[4] http://newmachineparts.blogspot.com/2012/09/pattern-shop.html
[5] Bawa, H S (2004). Manufacturing Processes
[6] http://mechanicalinventions.blogspot.com/2012/12/types-of-patterns.html
[7] http://www.me-mechanicalengineering.com/tools-in-foundry-shop/
[8] http://www.americanmetaltreatinginc.com/ht101.htm
[9] http://newmachineparts.blogspot.com/2012/09/heat-treatment.html
[10] http://www.brighthubengineering.com/manufacturing-
technology/74097-heat-treatment-annealing-and-tempering/
[11] http://www.tpub.com/steelworker1/9.htm
[12] http://collections.infocollections.org/ukedu/ru/d/Jgtz077ce/3.html
[13] http://www.saarstahl.com/arten_der_waermebehandlung.html?&L=1
[14] Heat Treatment : Principles and Techniques book by T. V. Rajan, C. P.
Sharma, Ashok Sharma from page 164
