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Dr. HABEEB HATTAB HABEEB
Office: BN-Block, Level-3, Room-
088
Email: hbuni61@yahoo.comExt. No.: 7292
UNITEN
University TENAGA Nasional Lecturer: Habeeb Al-Ani
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional
mailto:hbuni61@yahoo.commailto:hbuni61@yahoo.comhttp://www.dewittindustries.com/cgibin/ibrowse/images/of_12/animations/mechanical/gear/gearhttp://www.dewittindustries.com/cgibin/ibrowse/images/of_12/animations/mechanical/gear/gear8/2/2019 Cam 13 Inference Engine
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University TENAGA National
College Of EngineeringMechanical Department
Academic Year2008-2009
Lecture Note
University TENAGA Nasional Lecturer: Habeeb Al-Ani
UNITEN
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional
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CAMUniversity TENAGA Nasional Lecturer: Hab
eeb Al-Ani
Computer Aided Manufacturing
UNITEN
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional
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Computer Aided Process
Planning(CAPP)
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Process Planning
Principle activity of manufacturing engineeringincludes
1. Deciding which process and methods to be
used in what sequence2. Determining tooling requirements
3. Selecting production equipment and
systems4. Estimating cost of production of selected
process, tooling, and equipment
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Computer Aided Process Planning (CAPP)
CAPP is an automated process planning, can
be divided into two main sytems1. Retrieval Systems
2. Generative Systems
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Retrieval CAPP systems
Based on group technology (GT) and part classification
and coding a standard process plan is stored in
computer files for each part code number.
GT: Similar parts identified and grouped together in
order to take advantage of their similarities in
design and production.
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Generatival CAPP systems
Alternative to Retrieval systems. Rather than retrieving and
editing an existing plans from a data base, a generativesystem creates the process plan using systematicprocedures that might be applied by a human planner.
In fully Generative CAPP system, a process sequence isplanned without human assistance and predefinedparts.
It is a branch of artificial inteligence Expert Systems.
Computer Programs are capable of solving complexproblems that normally requires a human.
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Generative CAPP systems (continue)
Several ingredients needed
1. Knowledge Base: Technical knowledge of manufacturing
and the logic used by a succesfull process planners must
be captured and coded into a computer program.
Generative CAPP systems use the knowledge base to
solve the process planning problems and to create route
sheets.
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Generative CAPP systems (continue)
2. Computer Compatible Part Description: Description
contains all the data needed to plan the process
sequence. For example
i. Geometric model of the part developed on a CAD
system.
ii. Group technology code number of part defining its
significant features is given.
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Generative CAPP systems (continue)
3. Inference Engine: A generative CAPP system
requires the capability to apply the planning logic
and process knowledge contained in the knowledge
base to a given part description. CAPP applies its
knowledge base to solve a specific problem of
planning the process for a new part. This procedure
is called InferenceEngine
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Benefits of CAPP systems
1. Process rationalization and standardization (logical
and consistent)
2. Increased productivity (greater number of process
plans to be developed)
3. Reduced lead time
4. Improved legibility
5. Interfacing with other programs (cost estimation,
etc..)
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Design for Manufacturing and Assembly (DFM/A)
To implement DFM/A, a company must make
changes in its organizaitonal structure and
design principles and guidelines.
1) Organizational changes need to be done to have
better intraction between design and MFG
personnel.
Organizational changes must contain :
a)Team formed of designer, manufacturing
engineers, quality engineers, material engineers..
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(DFM/A)(cont.)
b)Designers must spend some time in
manufacturing area.c)A manufacturing engineer should consultthe designers.
2) One of the guide lines in designing is tomake it as simple as possible, but in designfor assembly, additional features arerequired, such as; to be technically good in
manufacturing, is it safe from copying( cancompetitors learn the secrets of ourproduct by reverse engineering?).
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Benefits of DFM/A
1. Shorter time to bring product to themarket
2. Smoother transition into production
3. Fewer components in final product4. Easier assembly
5. Lower cost of production
6. Higher product quality7. Greater customer satisfaction
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Design for Quality (DFQ)
Traditional quality control has been concerned
with detecting the or quality in manufactured
products and taking corrective action to
eliminate it.The modern view of quality control
encompasses a broader scope of activities
including robust design and statistical processcontrol.
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Design for Quality (DFQ)(continue)
Robust Design: Products function and
performance is not sensitive to the variations in
design and manufacturing parameters. It
involves the design of both the product and
process.
Statistical Process Control(SPC): Involving the
use of statistical methods to assess and analyze
the variations in process. This method includes
keeping records of production data and charts.
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional
D i f Lif C l
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Design for Life Cycle
Factors associated with life cycle
1)Delivery: Transport cost, delivery time, etc..2)Installation: Utility requirements.
3)Reliable: Service life, failure rates, etc..
4)Maintaining: Design modularity, maintenance
requirements.
5)Service: Spare parts, field service.
6)Human factors: Complexity of controls, risks, etc..
7)Upgrading: Compatibility to the future designs.
8)Disposability: Recycling of components, waste
hazards, etc..
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional
D i f C
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Design for Cost
In manufacturing our main aim is to reduce the cost of
production. Of course we need to make the processes
easy and quality high. Choosing the best material and
manufacturing processes among all the available
materials and processes is a complex decision making.
In cost reducing there is two main factors
1) Role of materials
2) Role of manufacturing processes
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Role of Materials
Understand the functional requirements of each part,
choosing criteria will include
1) Mechanical properties of the material: Strength,
toughness, ductility, hardness, etc..
2) Physical properties of the material: Density,
melting point, thermal expansion, etc..
3) Chemical properties of the material: Oxidation,
corrosion, etc..
4) Shape of the material:Need to select the shapewith respect to the design, therefore it requires
less additional process.
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Role of Materials (continue)
5) Manufacturing properties of the material: Need to
select the suitable material for the process that is
going to be applied.
6) Material supply: Location of the plant, location of
the country, politics in the country affects the
availabitiy of the material. Therefore the cost.7) Material cost: Cost of a raw materialdepends not
only on the material itself but also on its shape,
size and condition. Also, price of a material
decreases as the volume increases.Demand isanother aspect in the price of a material.
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Role of Materials (continue)
8) Product design: Cost of material is a significant
portion of product cost. This cost can be reduced
by optimization in design or reducing thickness.
But minimization in material thickness may cause
problems in manufacturing.
9) Substitution of materials: New products appearcontinually in the market to substitude the
materials in use. The purpose of substitution is to
reduce the cost of the material, to improve
manufacturing and assembly, to reducemaintenance, etc...
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Role of Manufacturing Processes
Proper selection of manufacturing processes andmachinery depends on various considerations like:
1)Properties of the work material
2)The shape and the size of the work material
3)Surface finish and dimensional tolerances
4)Quantity of the production
5)Functional requirements
6)Process capabilities.
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Manufacturing Cost
1) Material cost
2) Tooling cost
3) Fixed costs
4) Capital costs
5) Direct labor costs
6) Indirect labor costs
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Manufacturing Cost and Production Rate
Approximate cost division
Design 5%
Material 50%
Direct labor 15%
Overhead 30%
Of course the direct labor costs changes with respect to the
manufacturing volume. High volume type of manufacturing
includes dedicated machinery which needs less direct labor.On the other hand small volume productions needs more direct
Labor since the machinery used is general purpose type of
Machines and needs more human interaction.
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Cost Reduction
Cost can be reduced by
Simplifying part design
Allowances of rougher surface finish and broader
tolerancing
Using less expensive material
Investigating the alternative ways of
manufacturing(see the figure next slide)
Using efficent machinery Since manufacturing adds value to materials by
using value analysis methods we can reduce the
cost.
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Methods of Making a Part
Various methods of making a simple part:(a) casting or powder metallurgy.(b) forging or upsetting.
(c) extrusion.
(d) machining.
(e) joining two pieces.
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Value Analysis
Value analysis consists of six phases
Information phase: gather data and determinecost
Analysis phase:Identify problems andopportunities
Creativity phase:Seek ideas to solve problems
Evaluation phase: Select ideas and identify costsinvolved.
Implementation phase:Take necessary actions toaccomplish the task
Review phase: Analyze to see if any adjustment isneeded
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L t D HABEEB ALANI U i it TENAGA N i l
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