ME 142 Engineering Drawing

and Graphics

Instructor Details

Col ( R ) Mumtaz Yousafi• MSC ( Machine design )

NUST Rawalpindi • B.E. ( Mechanical Engineering)

NED Engineering UniversityKarachi

Pre Requisites

• Drawing Instruments• Basic Knowledge of Geometry• Basic Knowledge of units & conversion• Basic Knowledge of computers

• Pre requisites & Introduction• Dimension, sheet planning & use of dwg instruments • Orthographic projections • Engineering Geometry WEEK 1 to 7• Fits and tolerances • Geometrical dimensioning & tolerances• Manual Drawing practice• 1 st Sessional WEEK 8

• Introduction to AUTOCAD • 2 D Modeling & practice WEEK 9 to 18• 2 nd Sessional • Introduction to 3 D Modeling & practice • Course Review WEEK 19• Final Examination WEEK 20

COURSE OUTLINE

Details of Course OutlinePart-I • Introduction. Types of lines, lettering, dimensioning, use of pencil and drawing

instruments, planning of drawing sheet. • Projections. Types of projections, orthographic projections, plane of

projections, four quadrants, projection of points, projection of straight lines, examples with different quadrants, traces of a line, true length of a line, inclination to both the planes, projection of oblique and auxiliary planes.

• Use of instruments and letter writing practice• Engineering Geometry• Allowances and Tolerances• Geometric Dimensioning as per ANSI 14.5• First angle and third angle projection engineering drawing practice.• Geometrical construction engineering drawing practice.Part - II• Introduction to computer aided engineering drawing and use of

software/package (AUTOCAD).• 2 D & 3 D drawing including solid modeling

TEXT BOOKS FOR REFERENCE

• Engineering Drawing by A W Boundy• Machine Drawing by Ajeet Singh• Engineering Graphics with AUTOCAD by James

D Bethune

Overview of an Engineering Drawing

(WEEK 1)

LECTURE OBJECTIVES

Drawing standards

Graphics language

Engineering drawing

Traditional Drawing Tools

Drawing scales

Drawing Symbols

GRAPHICS LANGUAGE

1. Try to write a description of this object.

2. Test your written description by having someone attempt to make a sketch from your description.

Effectiveness of Graphics Language

The word languages are inadequate for describing the

sizesize, shapeshape and featuresfeatures completely as well as

concisely.

You can easily understand that …

Graphic language in “engineering application” use

llinesines to represent the surfacessurfaces, edgesedges and contourscontours

of objects.

A drawing can be done using freehandfreehand, instrumentsinstruments or computercomputer methods.

Composition of Graphic Language

The language is known as “drawingdrawing” or “draftingdrafting” .

Freehand drawingFreehand drawing The lines are sketched without using instruments other

than pencils and erasers.

Example

Instrument drawingInstrument drawing Instruments are used to draw straight lines, circles, and

curves concisely and accurately. Thus, the drawings are

usually made to scale.

Example

Computer drawingComputer drawing The drawings are usually made by commercial software

such as AutoCAD, solid works , PRO – E, etc.

Examples

Example of CAD

Example of CAD

Example of CAD

Example of CAD

Simple CAD/CAE/CAM Product Lifecycle

DesignCAD

AnalysisCAE

ManufacturingCAM

Engineering Drawing

Elements of Engineering Drawing

Engineering drawing are made up of graphics languagegraphics language

and word languageword language.

Graphicslanguage

Describe a shape(mainly).

Wordlanguage

Describe size, location andspecification of the object.

Basic Knowledge for Drafting

Graphicslanguage

Wordlanguage

Linetypes

Geometricconstruction Lettering

Projectionmethod

Traditional Drawing Tools

Traditional Drawing Tools

TECHNICAL DRAWING BOARD

1. T-Square 2. Triangles

DRAWING TOOLS

3. Adhesive Tape 4. Pencils

2H or HB for thick line4H for thin line

DRAWING TOOLS

5. Sandpaper 6. Compass

DRAWING TOOLS

7. Pencil Eraser 8. Erasing Shield

DRAWING TOOLS

9. Circle Template 10. Tissue paper

DRAWING TOOLS

11. Sharpener 12. Clean paper

DRAWING TOOLS

Drawing Standard

Introduction

StandardsStandards are set of rules that govern how technical

drawings are represented.

Drawing standards are used so that drawings convey

the same meaning to everyone who reads them.

ISO International Standards Organization

Standard Code

ANSI American National Standard InstituteUSA

JIS Japanese Industrial StandardJapan

BS British StandardUK

AS Australian StandardAustralia

Deutsches Institut für NormungDINGermany

Country Code Full name

Drawing Sheet

Trimmed paper ofa size A0 ~ A4.

Standard sheet size (JIS)

A4 210 x 297

A3 297 x 420

A2 420 x 594

A1 594 x 841

A0 841 x 1189

A4

A3

A2

A1

A0(Dimensions in millimeters)

Drawing space Drawingspace

Title block

d

d

c

c

cBorder lines

1. Type X (A0~A4) 2. Type Y (A4 only)

Orientation of drawing sheet

Title block

Sheet size c (mm) d (mm) A4 10 25 A3 10 25 A2 10 25 A1 20 25 A0 20 25

SAMPLE OF DRAWING SHEET

Drawing layout

All engineering drawings should feature a title block.

The title block should include:

Title:- title of the drawingName:- name of the person who produced the drawingChecked:- before manufacture, drawings are usually checkedVersion:- many drawings are amended, each revision must be notedDate:- the date the drawing was produced or last amendedNotes:- any note relevant to the drawingScale:- the scale of the drawingCompany name:- name of the companyProjection:- the projection system used to create the drawing

SAMPLE OF ENGINEERING DRAWING

Drawing Scale

Drawing Scales

ScaleScale is the ratio of the linear dimension of an element

of an object shown in the drawing to the real linear

dimension of the same element of the object.

Size in drawing Actual size

Length, size

:

Drawing Scales

Designation of a scale consists of the word “SCALE”

followed by the indication of its ratio, as follow

SCALE 1:1 for full size

SCALE X:1 for enlargementenlargement scales (X > 1)

SCALE 1:X for reductionreduction scales (X > 1)

Dimension numbers shown in the drawing are correspond

to “true size” of the object and they are independent of

the scale used in creating that drawing.