working drawing.pptx

8/14/2019 Working Drawing.pptx

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Chapter 14

Working Drawing


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TOPICS

Introduction

Detail drawing

Assembly drawing

Assembly section

Dimensioning


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In t roduc t ion


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DEFINITION

Work ing d rawing is a set of drawing usedduring the work of making a product.

Working d raw ing

Detaildrawing

A s s e m b l ydrawing


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DEFINITION

Detai l dr awin g is a m ult iv iew representa t ion

of a single part with d imens ions and notes .

Ass em bly d raw ing is a drawing of variousparts of a machine or structure assembled in

their relative working positions.


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Detai l dr awin g conveys the in fo rmat ion and i n s t ruc t i ons for manufacturing the part.

4. functional relationship among various

components.

1. completed shape of the product.

2. overall dimensions.

PURPOSE

Ass em bly d rawing conveys

3. relative position of each part.


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Detai l Draw in g


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INFORMATION IN

DETAIL DRAWING

2.1 Shape description

2.2 Size description

2.3 Specifications

1. General information

2. Part s information

Title block

Objects

views

Notes


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GENERAL INFORMATION Name of company

Title of drawing (usually parts name)

Drawing sheet number

Name of drafter, checker

Relevant dates of action

(drawn, checked, approved etc.)

Revision table Unit

Scale

Method of projection


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PART S INFORMATION

Orthographic drawing Pictorial drawing

Dimensions and Tolerances

Specifications

General notes

Type of material used

Surface finish

General tolerances

Part number, name,number required

Shape

Size

Heat treatment


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If not the case ,

- apply enou gh spac ing between parts.

-draw all parts using the sam e sc a le .

-Otherwise, the scale should be clearly note

under each parts drawing .

Draw one part to one sheet of paper .

RECOMMENDED PRACTICE

Standard parts such as bol t , n u t , p in , bear ing

do not require detail drawings.


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Part No., Part name, material, Number required

NotesUnit, fillets & rounds sizes etc.

Completed dimension

orthographic drawing

Title block

PLACING AN INFORMATION(This course)


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EXAMPLE : Interpreting detail drawing

General note

Revision table

Title block

1. Orthographicviews

2. Dimensions& Tolerances

3. Surfacefinishing

ProjectionGen. tolerance


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A ss em b ly Draw ing


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1. Exploded assembly drawings

3. Detail assembly drawings

TYPES OF ASSEMBLY DRAWING

2. General assembly drawings.

The parts are separately display, but they are aligned

according to their assembly positions and sequences.

All parts are drawn in their working position.

All parts are drawn in their working position with a

completed dimensions.


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1. EXPLODED ASSEMBLY

Pictorial representationFinished product


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1. EXPLODED ASSEMBLY

Orthographic representation


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2. GENERAL ASSEMBLY

Pictorial Orthographic


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Only dimensions relate tomachines operation aregiven.

Only dimensions relate to

machines operation are given

in tabulated form (not shown).

2. GENERAL ASSEMBLY


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2. GENERAL ASSEMBLY


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3. DETAILED ASSEMBLY(working-drawing assembly)


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- Assembled parts

- Reference numbers

General notesTitle block

Part list

PLACING AN INFORMATION(This course)


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PART LIST (BOM) (This course)

NO. PART NAME REQD. MATL. & NOTE

1 SUPPORT 2 Cast Iron

2 SHAFT 1 Stainless Steel

3 SET SCREW 1 Stainless Steel,M3 HEX SOCK CUP PT

Locate above or beside the title block.

Fill the table from the bottom.


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EXAMPLE : Another allowable place for BOM


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STEPS TO CREATEASSEMBLY DRAWING

4. Draw a view of m ajor par t s according to a

selected viewing direction.

3. Choos e major pa r ts , i.e. parts that have

several parts assembled on.

1. Analyze geometry and dimensions of all partsin order to understand the assembly steps and

overall shape of device or machine.

2. Select an appropriate view.


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6. Applysec t ion t echn iqu e

where relativepositions between adjacent parts are needed

to clarify.

7. Add bal loons , notes and dimens ions (if any).

5. Add detail view of the remaining parts at their

working positions.

8. Create BOM.

STEPS TO CREATEASSEMBLY DRAWING


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GENERAL PRACTICE

The num ber o f v iews can be one, two, threeor more as needed, but it should be minimum .

A good view ing d i rec t ion is that represents all

(or most) of the parts assembled in their working

position.


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Part A Part B

EXAMPLE : Selection of a necessary view

Given

Student A Student B

Which is an appropriate view for assembly drawing ?


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GENERAL PRACTICE

Hidden l ines usually omit unless they areabsolutely necessary to illustrate some

important feature that the reader might

otherwise miss.


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EXAMPLE : Hidden lines omit o r n o t ?

Part A

Part B

A

B

C

Good Poor


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Part A

Part B

A

B

Good Poor


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Part A

Part B

A

B

Good Poor


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GENERAL PRACTICESec t ion t ech n ique is usually need to clarify

mating of the parts.

Correct

Better

Part A

Part B

OFF

Use different section line styles for adjacent parts.

ONColor


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Do no t draw section lines on sectional view of

standard parts.

- Threaded fastener

- Washer- (longitudinal cut of) Solid shaft, Pin, Key

SECTION LINE PRACTICE


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EXAMPLE 1 : Assembly steps

3 PIN, Steel, 1 REQD.

2 ARM, Steel, 1 REQD.

1 CLEVIS, Steel, 1 REQD.


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EXAMPLE : Section line practice

A

BWhich is an appropriate

full section view of thisassembly ?

Good Poor

OFF ONColor


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3 TAPER PIN, Steel, 1 REQD.

2 SHAFT, Steel, 1 REQD.

1 SUPPORT, Steel, 1 REQD.


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A B

Good Poor

Which is an appropriatefull section view of thisassembly ?

C D

OFF ON

Color


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3 PIN, Steel, 1 REQD.

2 ARM, Steel, 1 REQD.

1 CLEVIS, Steel, 1 REQD.


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A

B

Good Poor

OFF ONColor

Which is an appropriate

section view of the joint ?

C


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LEADER LINE PRACTICE

Drawn in the ob l ique direction.

Drawn from the inside of the part to the balloon

and placed a filled circle at the beginning of a line.

12


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Shaft

Housing

Bearing

Coverplate

Capscrew

EXAMPLE


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1. Assemble steps.

2. Function of each part in machine.

3. Design concept.

INTERPRETING ASSEMBLYDRAWING

EXAMPLE 1 S h f hi h i


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EXAMPLE 1 : S haft support on a machine housing

Assemble steps

1. Install bearing to the shaft.

2. Install the bearing-shaft unit to

the housing.

3. Install the cover plate.

4. Tighten the screw.



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1. B earing :

Support the rotating shaft.

2. Cov er :- Control an axial movement.

- Prevent the bearing unit from

rotation.

Functions of main parts




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Av o i d direct contact between

rotating shaft and housing as well

as cover plate by using a bearingand clearance holes.


Design concept

EXAMPLE 2 L k i i


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1. Wrap a packing to the shaft.

2. Install studs to the casing.

3. Install the gland ring where its

holes align with stud.

4. Place the washer and

tightening the nut.

PackingCasing

Gland

EXAMPLE 2 : Leakage prevention unit

Assemble steps

EXAMPLE 2 L k ti it


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1. Pack ing :- Preventing the leakage of a

fluid inside the casing.

2. Gland :- Press the packing to make it

radial expand and press theshaft surface.

PackingCasing

Gland


Function

EXAMPLE 2 L k g ti it


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Avoid direct contact between

rotating shaft and casing as well

as gland rings hole.

PackingCasing

Gland


Design concept

EXAMPLE 3 Fi i g t h ft


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EXAMPLE 3 : Fixing parts on a shaft .

1. Place the keys on the

key seats.

2. Insert the parts to the

shaft until their surfaces

lean against the shoulder.

3. Insert collar and then pin

or retaining ring into the

groove.

Assemble steps

EXAMPLE 3 : Fi ing parts on a shaft


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EXAMPLE 3 : Fixing parts on a shaft .

1. K ey :

- Preventing rotational

movement of parts.

2. Pin and re tainin g r ing :

- Prevent axial movement

of parts on the shaft.

Function

EXAMPLE : Fixing parts on a shaft


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EXAMPLE : Fixing parts on a shaft .

Retaining ring can resist

lower axial force than collar

& pin unit.

Design concept

EXAMPLE : P arts with tapered holes on tapered shaft


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EXAMPLE : P arts with tapered holes on tapered shaft.

1. Insert the part on the

tapered end of the shaft.

2. Insert the washer(non-standard).

3. Tightening the nut.

Assemble steps



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1. Wash er :

- Improve the distribution

the tightening force on

the part.

Function



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Length of the tapered

portion and depth of the

tapered hole require acalculation.

Design concept

EXAMPLE : Parts having preloaded spring


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1. Insert the spring into the casing.

2. Tighten the rod to the spring

loader.3. Close the cap and tighten.

Spring infree length

Assemble steps



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1. Spr ing p lun ger :

- Transmit a force from rod to

spring.

- Keep the spring in a position.

Function



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Spring plunger has a spherical

surface contacts to the cap;

therefore, the rod can align itself

to original position.

Design concept


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Mating o f Par ts

POINTS TO CONSIDER


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1. Surface finishing

2. Tolerance

- Size- Geometry

POINTS TO CONSIDER

SURFACE FINISHING


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SURFACE FINISHING

1. To control the accuracy in positioning and

tightness between mating parts .

2. To reduce the friction, especially for the part

moves relative to other parts.

Surface finishing means the quality of a surface.It relates to the level of roughness of a surface.

Purpose


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Surface Control Why do we need to control surface

characteristics?

Rough surfaces cause friction and wear It is difficult to make accurate measurements

from rough surfaces


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Surface Characteristics Roughness

Small hills and valleys found on a surface

Defined as the arithmetic average of the deviationsabove and below a mean height of a surface

Expressed in microinches or micrometers.


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Waviness

Surface irregularities greater than roughness

Expressed in inches or millimeters

Lay

Direction of tool marks on a machined surface.


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66 Autumn 2009

.25 inches.125 inSur face Cont ro l Sym bol

Material must be removed

Material must n o t be removed

Material removal not specified


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M

Parallel to line representing surface

Perpendicular to the line representing the surface

Both directions to the line representing the surface

Multidirectional marks

Circular

Radial

Lay particulate, non-directional, protuberant

C

R

P

Bar add ed

S y m b o lloca t ion


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24

Average roughness is 0.000024 inches, which isoften referred to as 24 microinches or inches.

Material must be removed.

2814

Maximum average roughness is 28 microinches.Minimum average roughness is 14 microinches.

Material must no t be removed.

45

R

Average roughness is 45 microinchesLines on the surface are radial with respect

to the center of the surface


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Assignment

You are to complete the drawing and thework sheets handed out.

They are due on

working drawing.pptx

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