Transcript Mechanical Drawing (MDP 115) FirstYear, Mechanical Engineering Dept., Faculty of Engineering, Fayoum University Dr. Ahmed Salah Abou Taleb.

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
Part One:




Review.
Dimensions, Limits, Fits and Tolerance.
Surface Roughness.
Standard Machine Elements (threads, fasteners,
Keys, spline, gears, pulleys, bearing, …….).
 Welding and Riveting Conventions.
Course Outlines (Cont.)
Part Two:





Introduction to Computer Graphics.
Wire Frame.
Applying solid modeling of mechanical components.
Assembly drawing.
Production Drawing.
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
Appearance
Name 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
Length, size
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
:
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.
FIRST ANGLE
PROJECTION
FOR T.V.
IN THIS METHOD,
THE OBJECT IS ASSUMED TO BE
SITUATED IN FIRST QUADRANT
MEANS
ABOVE HP & INFRONT OF VP.
OBJECT IS INBETWEEN
OBSERVER & PLANE.
PP
VP
FV
LSV
Y
X
TV
HP
ACTUAL PATTERN OF
PLANES & VIEWS
IN
FIRST ANGLE METHOD
OF PROJECTIONS
11
12
TOP
13
TOP
14
TOP
First angle
orthographic projection
15
FOR T.V.
ORTHOGRAPHIC PROJECTIONS
FRONT VIEW
L.H.SIDE VIEW
X
PICTORIAL PRESENTATION IS GIVEN
DRAW THREE VIEWS OF THIS OBJECT
BY FIRST ANGLE PROJECTION METHOD
Y
TOP VIEW
16
GRAPHICS COMMUNICATION
WITH ENGINEERING DRAWING
Orthographic
Projection
Object
Dimensioning
Working
drawing
Clear ?
Yes
Finish
Orthographic
projection
(convention)
No
Section Views
Section views
convention
PURPOSES OF SECTION VIEWS
Clarify the views by
 reducing or eliminating the hidden lines.
 revealing the cross sectional’s shape.
Facilitate the dimensioning.
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.
Section
lines
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.