Engineering graphics 2110013

Subject: Engineering

GraphicsSubject code: 2110013

PRESENTATION ON:

Presented by:Shah Juhi

Om institute of technology

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3Topic

Drawing toolsTypes of LinesLetteringDimensioningScalesCurves

ConicsOther

Projection symbolProjection of a pointProjection of lineProjection of planesSolidSection of solidOrthographic projectionIsometric projection


4Objectives in Drawing

Typical Drawing Equipment

Objectives in Drawing

1. Accuracy2. Speed3. Legibility4. Neatness

12 3 4

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6

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14

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Viewing-plane lineExtension line

Dimension Line

Center LineHidden Line

Break Line

Cutting-plane LineVisible Line

Center Line (of motion)Leader

VIEW B-BSECTION A-A

Section Line

Phantom Line


5Types of Lines

GOOD

Not uniform in style.

Not uniform in height.

Not uniformly vertical or inclined.

Not uniform in thickness of stroke.Area between letters not uniform.Area between words not uniform.

Example : Good and Poor LetteringOm institute of

technology

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7Important elements of dimensioning

Two types of dimensioning: (1) Size and location dimensions and (2) Detail dimensioning


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DIMENSIONS OF LARGE OBJECTS MUST BE REDUCED TO ACCOMMODATE ON STANDARD SIZE DRAWING SHEET. THIS REDUCTION CREATES A SCALE OF THAT REDUCTION RATIO,

WHICH IS GENERALLY A FRACTION..THAT RATIO IS CALLED REPRESENTATIVE FACTOR.

REPRESENTATIVE FACTOR (R.F.) =DIMENSION OF DRAWINGDIMENSION OF OBJECT

0 1 2 3 4 510 METERSDECIMETERS R.F. = 1/100

4 M 6 DM

PLANE SCALE SHOWING METERS AND DECIMETERS.

R.F. = 1 / 40,00,000DIAGONAL SCALE SHOWING KILOMETERS.

0 100 200 300 400 500100 50

109876543210 KMKM

KM

569 km459 km

336 km222 km

Scales


10CLASSIFICATION OF CURVES

CURVES

CONIC SECTIONS ENGINEERING CURVES

1. CIRCLE2. ELLIPSE3. PARABOLA4. HYPERBOLA5. RECTANGULAR HYPERBOLA

1. CYCLOIDAL CURVES/ROULETTESa.Cycloidb.EpiCycloidc.Hypocycloidd.Trochoids(Superior & Inferior)e.Epitrochoids(Superior & Inferior)f.Hypotrochoids(Superior&Inferior)2. INVOLUTE3. SPIRALSa.Archimedianb.Logarithmicc.Hyperbolic4. HELICESa.Cylindricalb.Conical5. SPECIAL CURVES


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ELLIPSE

1.Concentric Circle Method

2.Rectangle Method

3.Oblong Method

4.Arcs of Circle Method

5.Rhombus Method

6.Basic Locus Method (Directrix – focus)

HYPERBOLA

1.Rectangular Hyperbola (coordinates given)

2 Rectangular Hyperbola (P-V diagram - Equation given)


PARABOLA

1.Rectangle Method

2 Method of Tangents ( Triangle Method)


Methods of Drawing

Tangents & Normals

To These Curves.

Methods in Conic sections


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ELLIPSE CYCLOID SPIRAL HELIX

1. Involute of a circle a)String Length = D

b)String Length > D

c)String Length < D

2. Pole having Composite shape.

3. Rod Rolling over a Semicircular Pole.

1. General Cycloid

2. Trochoid ( superior) 3. Trochoid ( Inferior) 4. Epi-Cycloid

5. Hypo-Cycloid

1. Spiral of One Convolution.

2. Spiral of Two Convolutions.

1. On Cylinder

2. On a Cone

Methods of DrawingTangents & Normals

To These Curves.

AND

Method of other Engineering curves

First angle system Third angle system

PROJECTION SYMBOLSOm institute of

technology

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A

a

a’ A

a

a’

Aa

a’

X

Y

X

Y

X

YFor Fv

For Tv

For Fv

For Tv

For Tv

For Fv

POINT A ABOVE HP& INFRONT OF VP

POINT A IN HP& INFRONT OF VP

POINT A ABOVE HP& IN VP

PROJECTIONS OF A POINT

PICTORIAL PRESENTATION

PICTORIAL PRESENTATION

ORTHOGRAPHIC PRESENTATIONS OF ALL ABOVE CASES.

X Y

a

a’

VP

HP

X Y

a’

VP

HP

a X Y

a

VP

HP

a’

Fv above xy,Tv below xy.

Fv above xy,Tv on xy.

Fv on xy,Tv below xy.


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X

Y

V.P.

X

Y

V.P. b’

a’

b

a

F.V.

T.V.

a b

a’

b’

B

A

TV

FV

A

B

X Y

H.P.

V.P. a’

b’

a b

Fv

Tv

X Y

H.P.

V.P.

a b

a’ b’Fv

Tv

For Fv

For Tv

For Tv

For Fv

Note:Fv is a vertical line

Showing True Length&

Tv is a point.

Note:Fv & Tv both are

// to xy &

both show T. L.

1.

2.

A Line perpendicular

to Hp &

// to Vp

A Line // to Hp

& // to Vp

Orthographic Pattern

(Pictorial Presentation)

(Pictorial Presentation)


16PROJECTIONS OF LINES

HPa 1

b 1

c 1

d 1

VPVP

a’

d’c’

b’

VP

a’ d’c’b’

For Fv

For T

v

For F.V.

For

T.V.

For

T.V.

For F.V.

HP

a

b c

d

a1’

d1’ c1’

b1’

HP

a1

b1 c1

d1

SURFACE PARALLEL TO HPPICTORIAL PRESENTATION

SURFACE INCLINED TO HPPICTORIAL PRESENTATION

ONE SMALL SIDE INCLINED TO VPPICTORIAL PRESENTATION

ORTHOGRAPHICTV-True Shape

FV- Line // to xy

ORTHOGRAPHICFV- Inclined to XY

TV- Reduced Shape

ORTHOGRAPHICFV- Apparent ShapeTV-Previous Shape

A B C


17PROJECTIONS OF PLANES

SOLIDSTo understand and remember various solids in this subject

properly, those are classified & arranged in to two major groups.Group A

Solids having top and base of same shape

Cylinder

Prisms

Triangular Square Pentagonal Hexagonal

Cube

Triangular Square Pentagonal Hexagonal

Cone

Tetrahedron

Pyramids

( A solid having six square faces) ( A solid having

Four triangular faces)

Group BSolids having base of some shape

and just a point as a top, called apex.


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SECTIONING A SOLID.An object ( here a solid ) is cut by

some imaginary cutting plane to understand internal details of that object.

The action of cutting is called SECTIONING a solid

&The plane of cutting is called

SECTION PLANE.Two cutting actions means section planes are recommended.

A) Section Plane perpendicular to Vp and inclined to Hp. ( This is a definition of an Aux. Inclined Plane i.e. A.I.P.) NOTE:- This section plane appears as a straight line in FV. B) Section Plane perpendicular to Hp and inclined to Vp. ( This is a definition of an Aux. Vertical Plane i.e. A.V.P.) NOTE:- This section plane appears as a straight line in TV.Remember:-1. After launching a section plane either in FV or TV, the part towards observer is assumed to be removed.2. As far as possible the smaller part is assumed to be removed.

OBSERVERASSUME UPPER PARTREMOVED SECTON PLANE

IN FV.

OBSERVER

ASSUME LOWER PARTREMOVED

SECTON PLANE IN TV.

(A)

(B)

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TOP VIEW

R22

204010

FRONT VIEWRIGHT SIDE

VIEW

1402080

SCALE: 1:1

303066

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Select a Front View

The object’s longest dimension should be presented as a width.

Inappropriate

First choice

GOOD

Second choice

Waste more space


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22Image of a part represented in First Angle Projection

http://upload.wikimedia.org/wikipedia/commons/5/59/First_angle_projection.svg

FOR T.V.

FOR F.V.FOR S.V.

PICTORIAL PRESENTATION IS GIVENDRAW THREE VIEWS OF THIS OBJECT

BY FIRST ANGLE PROJECTION METHOD

ORTHOGRAPHIC PROJECTIONS

FRONT VIEW

TOP VIEW

L.H.SIDE VIEW

X Y


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H

3-D DRAWINGS CAN BE DRAWN IN NUMEROUS WAYS AS SHOWN BELOW.ALL THESE DRAWINGS MAY BE CALLED

3-DIMENSIONAL DRAWINGS, OR PHOTOGRAPHIC

OR PICTORIAL DRAWINGS.HERE NO SPECIFIC RELATION

AMONG H, L & D AXES IS MENTAINED.

H

NOW OBSERVE BELOW GIVEN DRAWINGS.ONE CAN NOTE SPECIFIC INCLINATION

AMONG H, L & D AXES.ISO MEANS SAME, SIMILAR OR EQUAL.

HERE ONE CAN FIND EDUAL INCLINATION AMONG H, L & D AXES. EACH IS 1200 INCLINED WITH OTHER TWO. HENCE IT IS CALLED ISOMETRIC DRAWING

H

L

IT IS A TYPE OF PICTORIAL PROJECTIONIN WHICH ALL THREE DIMENSIONS OF

AN OBJECT ARE SHOWN IN ONE VIEW AND IF REQUIRED, THEIR ACTUAL SIZES CAN BE

MEASURED DIRECTLY FROM IT.

IN THIS 3-D DRAWING OF AN OBJECT, ALL THREE DIMENSIONAL AXES ARE MENTAINED AT EQUAL INCLINATIONS

WITH EACH OTHER.( 1200)

PURPOSE OF ISOMETRIC DRAWING IS TO UNDERSTAND OVERALL SHAPE, SIZE & APPEARANCE OF AN OBJECT PRIOR TO IT’S PRODUCTION.

ISOMETRIC DRAWING TYPICAL CONDITION.Om institute of

technology

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