Mechanical Drawing(MDP 115)

FirstYear,

Mechanical Engineering Dept.,

Faculty of Engineering,

Fayoum University

Dr. Ahmed Salah Abou Taleb

Aims of the course

This module is designed to provide students with an analysis of mechanical drawings. Comprehensive study of fasteners. Methods of assembling various mechanical parts together with and without locking devices (working drawings, dimensional tolerance, fits, surface finishing).

Course Outlines

Review.

Dimensions, Limits, Fits and Tolerance.

Surface Roughness.

Standard Machine Elements (threads, fasteners, Keys, spline, gears, pulleys, bearing, …….).

Welding and Riveting Conventions.

Part One:

Course Outlines (Cont.)

Introduction to Computer Graphics.

Wire Frame.

Applying solid modeling of mechanical components.

Assembly drawing.

Production Drawing.

Part Two:

Teaching and Learning Methods

Power Point Lectures.

Computer Program (Auto CAD).

Class Work Drawings.

Home Work Assignments.

Quizzes.

Weighting of Assessment

Final Exam 80

Mid Term Exam 20

Class Work Drawing 20

Home Work Assignment 20

Oral 10

Total Marks 150

Review - Instruments

The following is the list of drawing instruments and other

drawing materials required for preparation of drawing work:

1. Drawing board

2. T-Square

3. Set- Triangles – (30o – 60o and 45o)

4. Instrument box consists of compasses and dividers

5. Mechanical Pencil

6. Rubber or eraser

7. Erasing shield

8. Scotch-tape

9. Duster or handkerchief

10.Drawing sheet

Review - Basic Line Types

Types of Lines AppearanceName according

to application

Continuous thick line Visible line

Continuous thin line Dimension line

Extension line

Leader line

Dash thick line Hidden line

Chain thin line Center line

NOTE : We will learn other types of line in later chapters.

Review - Drawing Scales

Scale 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

:

Review - 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 enlargement scales (X > 1)

SCALE 1:X for reduction 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.

FOR T.V.FIRST ANGLE PROJECTION

IN THIS METHOD, THE OBJECT IS ASSUMED TO BE SITUATED IN FIRST QUADRANT

MEANS ABOVE HP & INFRONT OF VP.

OBJECT IS INBETWEENOBSERVER & PLANE.

ACTUAL PATTERN OFPLANES & VIEWS

IN FIRST ANGLE METHOD

OF PROJECTIONS

X Y

VP

HP

PP

FV LSV

TV

11

12

TOP

13

TOP

14

TOP

First angleorthographic projection

15

FOR T.V.

PICTORIAL PRESENTATION IS GIVEN

DRAW THREE VIEWS OF THIS OBJECTBY FIRST ANGLE PROJECTION METHOD

ORTHOGRAPHIC PROJECTIONS

FRONT VIEW

TOP VIEW

L.H.SIDE VIEW

X Y

16

Object

GRAPHICS COMMUNICATION

WITH ENGINEERING DRAWING

Workingdrawing

Clear ?

Orthographicprojection

(convention)

Section viewsconvention

Section Views

Orthographic Projection

Finish

Yes

No

Dimensioning

PURPOSES OF SECTION VIEWS

Clarify the views by

Facilitate the dimensioning.

reducing or eliminating the hidden lines.

revealing the cross sectional’s shape.

Let See the example

EXAMPLE : Advantage of using a section view.

SECTION LINING

Section lines or cross-hatch lines are used to

indicate the surfaces that are cut by the cutting

plane.

Sectionlines

Drawn with 4H pencil.

FULL SECTION VIEW

The view is made by passing the straight cutting plane

completely through the part.

TREATMENT OF HIDDEN LINES

Hidden lines are normally omitted from section

views.