tolerancing in isonrskumar/index_files/mech211/full... · tolerancing in iso international...

Tolerancing in ISO

International tolerance (IT) Grades

Minimum hole size is the basic size

Metric preferred hole based system of fits

Limit form vs. note form tolerancing

Hole Tolerance =

.025

Shaft Tolerance =

.016

Loosest fit =

40.025-39.975 =

.050

Tightest fit =

40.000 – 39.991 =

.009

Metric Tolerances-Standard representation

• If limits are shown up and down, largest limit up

• If shown side by side, smallest limit first

• For angular dimensions, it can be in general note or it can be

mentioned similar to that of linear dimensions

• Hole Basis fit: the basic size is the minimum dia of the hole

and fit is calculated based on this

• Shaft Basis fit: the basic size is the maximum dia of the shaft

and the fit is calculated base on this

Basic hole and shaft system-Imperial size

Hole Basis Fit

Interference fit Clearance fit

Shaft Basis Fit

Interference fit Clearance fit

Basic Size .500

Largest shaft

.500

Smallest hole

.500

0.500 is the lower limit hole

0.496 is the upper limit shaft

0.004 is the ALLOWANCE

0.496 is the upper limit shaft

0.003 is the shaft tolerance

0.493 is the LOWER LIMIT SHAFT

0.500 is the lower limit hole

0.003 is the hole tolerance

0.503 is the UPPER LIMIT HOLE

0.500 is the smallest hole

0.496 is the largest shaft

0.004 is the tightest fit

0.503 is the largest hole

0.493 is the smallest shaft

0.10 is the loosest fit

.503

.500 .496 .493

Example – Run Fit

• Used to limit the abatement in the geometric

or positional variation of features

Geometric tolerancing

Total flatness tolerance,

.05inch. This entire tolerance

zone may move up and down

within the size tolerance zone

Total height

tolerance .2 inches

Flatness tolerance

indication in

drawing

Example of feature control frames

Geometric

tolerance symbol

(Parallelism) Geometric

tolerance value

Reference Datum

Geometric

tolerance symbol

(Roundness)

Geometric

tolerance value

Size dimension

Dimensioning and

tolerancing symbols

Straightness of the axis

Roundness

Cylindricity

Drawing with GT - Example

Machine elements

Fasteners, gears, bearings, welding

MECHANICAL ENGINEERING

DRAWING

MECH 211

• Machine elements and standards

• Non-permanent fasteners – bolts and screws • Features, representation, assembly representation and note

• Other non-permanent fasteners

• Permanent fasteners – rivets, joining through

soldering, brazing and welding

• Springs

• Assembly drawings

• Machine elements: gears, cams, bearings, etc.

• Examples of mechanisms and representations

Content of the lecture

• Use to join two or more components

• Two major categories: • Non-permanent fastening methods

• Permanent fastening methods

• The Boeing 747 has 2.5 million fasteners!

Fasteners

• Bolts and nuts, machine screws, studs, pins,

rings, keys, etc.

• An assembly could be disassembled without

destroying the fastener or a part of the

assembly

Non-permanent fasteners

• Used to assemble machine parts through the friction obtained in a helical groove made on two conjugated parts

• The threads are cut or rolled in a blank of material (metal) while the conjugate part moves axially on the thread when turned

• Bolts and nuts must have the same geometric features in order to be mated.

Bolts, nuts and machine screws

Screw and thread terminology

• Screw Thread - A ridge

of uniform section in the

form of a helix on the

external or internal

surface of a cylinder.

• Major Diameter - The

largest diameter of a

screw thread.

• Minor Diameter - The

smallest diameter of a

screw thread.


• Axis – the longitudinal

center line of the original

work (blank) or hole

• Chamfer – the angular

relief at the beginning or

end of the thread to

allow easier engagement

with the mating part

• Crest – the peak of the

top of a thread

• Depth – the distance

between the crest and the

root

• Die – the tool used to perform external threads

• External thread – the screw thread on the outside of a cylindrical surface

• Internal thread – the screw thread on the inside of a cylindrical surface

• Lead – the distance that a screw will travel along the axis when turned by 360°


• Pitch – the distance

between corresponding

points on adjacent

thread forms, measured

parallel to the axis

expressed in 1 divided

by the number of pitch

in one inch

• Pitch diameter – the

diameter of an

imaginary cylinder that

is located equidistant

between the major and

the minor diameter


• Root – the bottom of the screw thread cut in a cylinder

• Tap – the tool used to thread holes

• Thread angle – the angle between the surfaces of two adjacent threads

• Thread series – the number of threads per inch for a given diameter


• ANSI Y14.6 - 1998

• Thread form

• Thread series

• Major diameter

• Class of fit

• Threads per inch

Thread specifications – imperial system

Form

• Shows some common thread forms

• Inch & Metric have same proportion

• Sharp V was original american national thread

• American national now has flattened root and crest to increase strength

• Unified thread is agreed as standard in US, Canada and Britain, the crest may be flat or rounded but the root is rounded. Otherwise similar to American national

Form

• ISO Metric is the most common of all the depth is smaller than that of unified national thread

• Knuckle thread is rolled or cast (used in light bulbs and sockets)

• Square and Acme threads are used for transmitting power

• Buttress thread takes pressure on one side ( to the axis)

Controls and positioning applications

Motion and measurement screws

Measuring thread pitch

• Pitch is the distance parallel to axis between corresponding points in adjacent thread

• Pitch is measured in millimeters for metric thread and indicated along with the major dia (eg. M10 X 1.5)

• For inch threads, it is mentioned as threads per inch

• Thread Pitch is measured with scale or a thread pitch gage

• Series depends on the pitch and the major dia of the

thread

• Coarse series – used for quick assembly and disassembly

of cast iron, soft metals and plastics (UNC) – Less TPI

• Fine series – used when a great deal of force is necessary

for assembly (UNF) - More TPI

• Extra fine series – used when the length of engagement is

short and the application calls for high degrees of stress

(UNEF) – Lot of TPI

Series

Series

• If it is not stated in the drawing, it is always assumed to be right

hand thread

• A bolt threaded into a tapered hole should be turned clockwise

• Some special cases (where the torque may loosen the fastener)

may require Left hand threads

• If Left hand threads are necessary it is indicated in the drawing

by the letters LH after the thread designation

Number

of starts

of a

thread

Single and multiple thread forms

• If it is not stated in the drawing, it is always assumed to be single thread

• Single thread has a single ridge in the form of helix and lead = pitch

• Multiple threads have 2 or more ridges running side by side • .

• The slope line is the hypotenuse of the right triangle whose short side = .5P

for single thread and p for double and 1.5 P for triple threads

• Multiple threads are required when small rotation must gives faster

movement at low required power (Eg. Toothpaste caps )

Thread Symbols

• Can use, simple, schematic or detailed as needed. Simplified is common

• Detailed is more pleasing, so for major dias >1” detailed is preferred

• Class 1 A an B – a loose fit where quick assembly is

required and play between parts is acceptable

• Class 2 A and B – a high quality general purpose

commercial class of fit for bolts, nuts and screws used in

mass production

• Class 3 A and B – a very high quality threaded fasteners

with a close fit used for precision assembly subjected to

vibrations

• A is for external threads and B is for internal threads

Class of fit

Thread notes

How to represent a thread

• Thread form symbol – M

• Nominal size – in mm

• Pitch size – in mm

• General purpose tolerance – a tolerance

class that includes a tolerance position and a

tolerance grade for both pitch diameter and

minor diameter

ISO representation of threads

Basic metric thread note

Complete threading - metric system

• The number of the tolerance grades

reflects the size of the tolerance

• For example, grade 4 < grade 6 <

grade 8 tolerances

• In addition to the tolerance grade, a

positional tolerance is required

• For external threads:

• Tolerance position e (large allowance)

• Tolerance position g (small allowance)

• Tolerance position h (no allowance)

• For internal threads:

• Tolerance position G (small allowance)

• Tolerance position H (no allowance)

Bolts, nuts and screws

• Large variety of bolts (dimensional, head

shape, etc.)

• Material, quality, finishing

• Grade


• Unfinished bolts are

not machined

anywhere except for

the thread portion

• Finished bolts have

machined face for

washer holding or

flush location on

parts


Fastener locking

Castellated nut

Fastener locking

Jam nut Durlock nut

Standard Cap Screws

• 5 different capscrews shown. Socket head can have different shapes of head

and sockets

• Sued in machines to pass through clearance hole to screw into another and

improve appearance

• Socket screws are used while in crowded condition

hexsize

heightth_height

Dia"-XXUNY-2A

Part representation

th_heightheight

Dia"-XXUNY-2A

machine screw

Part representation

Assembly representation

• Clips, rings, pins, etc.

Other non-permanent fasteners

Other non-permanent fasteners

• Clips, rings, pins, etc.

• Once assembled, the parts of the assembly (including the

fastener) would be destroyed to disassemble the assembly.

• Rivets, soldering, brazing, welding

Permanent fasteners

• Used to permanently fasten mechanical

components

Rivets

Riveting process

The headless end of the rivet is plastically deformed such

that keeps together two components

Fastening with rivets

Fastening with rivets

Common riveted joints

Self piercing rivets

Blind rivets

• Joining of two part using a third component –

filler that joins the parts when in liquid state

• Soldering and brazing – low temperature binding

materials – Sn-Pb, Cu-Ag alloys

• Limited capability to face thermo-mechanical

loading

Soldering, brazing, welding

• Very well regulated activity

• It requires license to practice

• Welders bear significant responsibility

• The activity is based on rigorous rules and regulations

• Designer prescribe welding based on mechanics of

materials calculations

• Symbols indicate the type of welding

Welding

Basic welding symbol

• Designed to store energy when

deflected and return the same

amount of energy when released

• Basically divided as Helical and Flat

springs

• Helical springs are sub divided as

– Compression Springs

– Extension Springs

– Torsion Springs

Springs

Helical Springs

Compression, Extension & Torsion

Machine elements

gears, bearings

Lecture 11

MECHANICAL ENGINEERING DRAWING

MECH 211

• Exam is on the 6th of December 2012

• Course evaluation is online

– Do not forget to do it from your myconcordia portal

– Important means to convey your thoughts about course

• Lecture 12 - Case Study and Make up lecture

• Held at the same time (8.45 AM to 11.30 AM) on

Monday the 3rd of December 2012

Machine elements

• Used to transmit power or support elements

that transmit power

• Gears, belts/pulleys, chain/sprockets,

cams/followers

• Shafts, bearings

• Springs, ratchets, clutches, brakes

Machine elements

Gear and pinion mechanisms – power transmission

Between two close-positioned shafts

Gears

• The profile of the tooth is a portion of an

involute (the curve generated by a line that

rolls without sliding on a circle)

Gears

• Meshing

require the

same geometry

of the teeth

• The rule of

meshing – the

transmission

ratio i

Gears

• Pressure angle is the direction of the

transmitted force versus the normal to the

center line

Gears

Gears nomenclature

This gear is not sectioned unless

something inside should be shown

A table containing cutting data must accompany the representation

Gears representation


A table containing cutting data must accompany the representation

Gears

• Rack representation (the cutting data is

included)

• Transmission of liner motion to

circular or vice versa

Worm and gear

• Worm and Gear representation

• Transmission of motion between

out of plane, perpendicular axes

Bevel gear assembly

• Bevel Gear representation

• Transmission of motion between in plane, perpendicular axes

Cams and followers

Reduce the high stress when

power is coupled to an idle shaft

Clutches

Bearings

Ball and roller bearings

Example of mechanisms

WORKING DRAWINGS

Production and Assembly Documentation

Technical Data Presentation

Lecture 11

• Design process

• Technical documentation

• Working drawings

• Assembly working drawings

• Component working drawing

• Title block

• Modifications and revisions

• How to simplify the design process

• Checklist of a good design

• Technical data presentation

Content of the lecture

• Developed for a new product

• Includes working drawings apart from

calculations, technology details, assembly scheme,

etc.

• Working drawings include: • Assembly working drawings

• Component working drawing

• Component working drawings for the same part

may look different for different processes

Technical documentation

• One working drawing is made for each non-standard component

• All the necessary information to carry out manufacturing must be contained within the drawing

• Recommendation: use a reference (textbook) when draw a working drawing

• Assembly working drawing contain the necessary information to perform the assembly of the system

Working drawings

Working drawings

Working Drawings

• Includes assembly and

detailed specs for

manufacture

• Neatly made and

checked

• Working drawings of

individual parts is

called detail drawing

• Details of individual parts may be drawn on single sheet or in

many sheets (one sheet per part), and assembly drawing done on

separate bigger sheet

• If drawn on single sheet, space must be considered for

dimensions and notes as well

• In a detailed

drawing of an

assembly, the part

name and the detail

number are located

within the drawing

area

Detail Drawings

• A drawing must match a certain format

• The scale should be selected to make sure

that the component would fit the format

• A preliminary evaluation should be

performed before the drawing is completed

• Take into consideration the space for

dimensions

Drawing Form

back Drawing Form Refer front inside cover

of the book for details

Ion Stiharu

Drawing Form

• Used to record important information and keep track of the parts

a) Name and address of the company

b) Title of the drawing

c) Drawing number

d) Names of the designers and date of completion

e) Design approval

f) Additional approval

g) Predominant drawing scale

Title blocks and drawing numbers

h) Supply code for

manufacturers

i) Drawing sheet side

letter designation

j) Actual or estimated

weight of the item

Title blocks and drawing numbers

• Bill of Materials BOM -

consists of itemized list of

parts shown on a detail or

assembly drawing

• This is done above the title

strip (numbered upward) or

on separate sheet

• It has the part numbers, title,

Qty, material and other

relevant info

• Drawing Numbers - all drawing should be numbered (lower

right or upper left corner of sheet) with serial numbers

indicating functionality of component or model No. of machine

• Revisions are required due to changes in design. So to keep track of all the modification, revisions need to be numbered and maintained

Modifications and Revisions

• The track of modifications is

kept on the drawing (some new

approaches are applied on CAD)

• If changes are considerable, new

drawing is made with

OBSOLETE stamped on old

1. Use text description whenever possible to eliminate

drawing completely.

2. Use text description whenever practical to eliminate

projected views.

3. Eliminate views where the shape can be given by

description e.g. HEX, SQ, DIA,

4. Show partial views of symmetrical objects.

5. Avoid elaborate, pictorial or repetitive detail.

How to simplify the design process

6. When necessary to detail threads, do not show them

over the whole length.

7. Eliminate detail of nuts, bolt heads, and other standard

parts. Show outlines and position only.

8. Reduce detail of parts on assembly drawing.

9. Avoid unnecessary hidden lines that add no

clarification.

10. Use sectioning only when it is necessary for the clarity

of the drawing.


11. Simplify graphics for holes and tapped holes by use

of the symbols.

12. Omit views with no dimensional or written

instruction.

13. Within limits, a small drawing is usually easier and

quicker to make than a large one.

14. When two parts are slightly different, complete

graphical representation of both parts is not

required. The note: SAME AS EXCEPT …….. Or

OTHERWISE SAME AS …. may be given.


15. Drawings made to modify stock or commercial

parts should be as plain as possible. Avoid detail.

16. Use standard abbreviations whenever possible.

17. Whenever necessary, enlarge small details on

larger parts for clarity.

18. Draw small parts large enough to avoid crowding

so they may be easy to read, but not unnecessarily

too large to ware space on the drawing.

19. Do not duplicate dimensions.


20. Substitute recognized standard symbols, to simplify

greatly the drawing of common objects.

21. Eliminate repetitive data by use of general notes.

22. When drafting, do so much free-hand drawing as the

work permits, in preference to using instruments.

23. Where practical, use geometric symbols instead of

notes.

24. Where acceptable, give rectangular coordinate or

tabular dimensioning instead of dimension lines.


• Assembly drawing shows how each component is

positioned with respect to the others

• Each component should be identified and listed in a parts

list

• General assembly - gives a general graphic description of

the shape

• Sectioned assembly - shows the hidden features and their

interdependence

• Installation or outline assembly - indicates how the parts,

shown separated, are assembled

• Pictorial assembly - usually isometric, indicates how the

parts, shown separated, are assembled

Assembly Drawing

General Assembly Drawing

Detail

drawing of

a

automobile

connecting

rod

General Assembly Drawing

Assembly drawing of a

automobile connecting

rod

The purpose is relation

ship between parts in

assembly than

individual shape.

Minimum number of

views must be used.

Here one view is

enough to show the

relationship

This is also called a sub-assembly because this forms a part of

the bigger assembly

Sectional Assembly Drawing

Assembly drawing of a

Grinder

The purpose is relation

ship between parts in

assembly than

individual shape.

Minimum number of

views must be used.

Here (only) two views

are needed to show the

relationship

In order to avoid hidden lines (common due to interaction of many

components in assembly) sectioning is done to improve clarity

Sectional Assembly Drawing

• To distinguish parts,

section lines are

drawn in different

directions

• Change of angle (not

45°) may be done if

needed

• Thin materials like

gaskets are shown as

thick lines in section

• Standard practice is

not to section bolts,

shafts, even though

section lines pass

through them

Outline Assembly Drawing

• Made specifically to

show how to install

or erect a machine

• This is also called

installation assembly

• It outline the

relationships of

exterior surfaces

Outline Assembly Drawing • In aircraft drafting, installation assembly gives

complete information for placing details of

sub assemblies in their final positions in

airplane

Pictorial Assembly Drawing

• Made specifically to

show how to install

or erect a machine

• Here use of

isometric views to

show separated parts

that need to

assembled

Pictorial Assembly Drawing

Tabular drawing (catalog)

• Thus one

drawing serves

for a range of

sizes covered.

• But there is a

serious risk of

misreading the

table.

Is one on which the dimension are replaced by letters, and

accompanying table lists the corresponding dimensions for a series

of sizes

Standardized drawing

• Drawing is

made without

dimensioned

• Copied by any

methods

• Dimensions

filled

accordingly

To avoid misreading of tables as in tabular drawing, yet simplify

drawing process

1. Is the drawing easy to read?

2. Are the part outlines distinct from dimension lines?

3. Is the lettering neat and clear?

4. Is all of the information on the drawing?

5. Will the drawing make a good print?

6. Have all the rules of standard drafting practices

been followed?

Checklist for a good design

7. Is the nomenclature correct? Will anyone

understand it the same way?

8. Is the drawing title truly descriptive?

9. Are all the necessary views given?

10. Are all the dimensions shown?

11. Are dimensions which are given twice?

12. Are all the notes properly located?

13. Could any of the notes be misunderstood?


14. Does the parts agree with the list?

15. Are the standard parts specified correctly?

16. Is the scale designated?

17. Are the finishes specified in the drawing?

18. Is heat treatment recommended?

19. Have standard manufacturing processes been

followed?

20. Can the part be produced simpler and more

economic?


21. Are the materials specified?

22. Are the standard parts used to the maximum

extent?

23. Are the suppliers for the standard parts indicated?

24. The design is yours. Are you ready to approve it?


• Technical communication require enhanced

ways to convey data and numerical

information MAG(TREN) PHASE(TREN) IMAG REAL MAG PHASE MAG(TREN) PHASE(TREN) IMAG REAL MAG PHASE MAG(TREN)

26.1287 -180.0000005 2.15324E-07 -26.0287 26.0287 -180.0000005 26.0287 -180.0000005 2.15324E-07 -25.3287 25.3287 -180.0000005 25.3287

26.1288 -180.0000317 -0.000809 -26.0289 26.02890001 -179.9982192 26.02880001 -179.9991098 -0.002295 -25.3289 25.3289001 -179.9948085 25.32880005

25.64784981 -131.6957183 2.04 -8.3 8.547022873 -193.8086224 20.20154096 -184.6022807 -10.33 44.3 45.48844798 -13.12584485 32.0486827

28.95132643 -97.96415498 -4.533 29.1 29.45094377 -8.853989418 22.51389166 -140.6652079 0.71 32.5 32.50775446 1.251493346 32.16345064

31.40878786 -77.13796096 -17.98 37.1 41.22730163 -25.85650422 26.25657366 -117.7034671 -15.48 31.5 35.0981538 -26.17082038 32.75039127

33.53802407 -62.16180586 -10.672 31 32.78553925 -18.99643745 27.34473459 -101.2522955 -4.442 31.9 32.20778421 -7.927328138 32.65995676

36.62170197 -31.43062462 0.213 35.2 35.20064444 0.346700343 28.873392 -71.19451205 2.424 43.4 43.46764056 3.196793128 35.68311352

39.44612293 -0.86542368 0.514 41.6 41.60317531 0.707897407 31.46910455 -41.07682595 1.688 41.4 41.43439808 2.334824517 38.36736318

42.34289628 5.519800663 1.966 40.2 40.24804537 2.799846426 36.7526083 -8.308747817 1.526 41 41.02838866 2.131537061 37.62401996

43.22825258 5.533797457 2.664 40 40.08861305 3.810272 38.52555318 -6.198037581 2.164 44.1 44.15306214 2.809267431 39.56490457

43.42345535 4.711813463 2.894 40.8 40.90250892 4.057272989 38.47142106 -1.212408047 0.455 46.2 46.20224048 0.564258374 41.41558569

43.13192018 2.204145796 0.57 42.9 42.90378655 0.761227802 40.15779561 2.080536161 2.38 43.6 43.6649104 3.124512684 43.32510672

42.58493131 1.937115398 2.099 41 41.05369412 2.930705805 41.13330389 2.511203738 4.429 42.7 42.92908153 5.921751583 43.23534688

42.48909705 1.329458943 1.006 43.7 43.71157783 1.31875001 41.4847043 2.613012505 1.196 40.8 40.81752584 1.679071923 43.13253484

42.39515945 0.906209117 1.407 42.7 42.72317461 1.887260061 41.89722585 2.460914778 1.107 42.5 42.5144146 1.492049174 43.38020583

42.01642917 0.434922695 -0.16 42 42.00030476 -0.21826858 42.21584113 1.789491348 0.388 42.6 42.60176691 0.521834454 43.12165663

41.93178682 0.322315106 1.66 41 41.03359112 2.31851401 42.23768816 1.499698185 0.96 43.6 43.61056753 1.261354636 42.68971114

42.17634917 0.610967193 -0.853 45.9 45.90792534 -1.064655224 42.73837796 1.195384347 -1.023 42.3 42.31236851 -1.385393831 42.46428749

42.38516948 0.060112993 -1.495 43.5 43.52568236 -1.968356085 43.150376 0.378874032 2.075 40.2 40.25351693 2.954809095 42.01836005

42.21847736 0.136864276 -1.826 42.1 42.13958087 -2.483528788 42.88837651 -0.254839101 0.634 40.5 40.50496212 0.896853268 41.9662661

41.88493263 -0.0657412 2.141 41.7 41.75492643 2.939152132 42.72700181 -0.079523756 0.391 41.5 41.5018419 0.539806914 41.79750398

42.1187724 -0.285318156 0.054 43.7 43.70003336 0.070800241 43.01028991 -0.031345619 -0.7496 44.2 44.20635588 -0.971601797 42.06493548

42.21872329 -0.463976165 -1.432 43 43.02383786 -1.90737779 43.3419977 -0.735660919 -0.744 44.1 44.10627547 -0.966530983 42.14755347

42.0851383 -0.304524959 -1.662 42.5 42.53248457 -2.239460898 42.77942424 -0.931461865 1.408 43.6 43.62272875 1.84964292 42.36594684

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43.27557789 0.150206713 0.689 44 44.00539423 0.897126498 43.03080871 -0.802164363 -0.2 43 43.00046511 -0.266490076 43.3552619

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43.27713138 -0.142675763 0.075 42.9 42.90006556 0.100167345 43.22184571 -0.19592373 -0.775 42.5 42.50706559 -1.044689606 42.93498764

43.39393482 -0.760324385 1.5824 43.8 43.82857504 2.069073663 43.62615617 0.039617194 -0.7336 43.4 43.40619966 -0.968391277 43.08576098

43.44211693 -0.248308477 -0.845 43.5 43.50820641 -1.112847021 43.74110992 0.134739828 0.1445 43.9 43.90023782 0.188592488 43.21904868

43.34311043 -0.402616155 -0.923 44.8 44.80950713 -1.18027955 43.80903787 0.027279783 -0.2284 44.7 44.70058351 -0.292757095 43.36914079

43.47586226 -0.696349923 1.4439 44.3 44.32352476 1.866819388 43.86205963 0.188895265 -0.1262 44.1 44.10018057 -0.163961624 43.5524267

43.49149462 -0.542411587 -0.598 44 44.00406349 -0.778653791 43.89565706 0.160713339 -1.591 46.2 46.2273867 -1.972328475 44.14027564

43.99602958 -0.749872392 -2.136 44.5 44.55123451 -2.74808818 44.17085189 -0.313995915 -0.7122 42.8 42.80592516 -0.953324497 44.19008557

44.11254763 -0.741396757 1.649 43.5 43.53124396 2.170931552 44.12129671 -0.2970196 -0.135 43.6 43.600209 -0.17740609 44.22242046

44.09434601 -1.032328006 -1.025 46.6 46.61127144 -1.260058061 44.63847421 -0.321554774 -1.473 44.4 44.42442717 -1.900129293 44.30978535

44.26422053 -1.195217451 -1.1115 45.2 45.21366422 -1.408659887 44.70583373 -0.359618163 -1.6215 44.7 44.72940042 -2.077503081 44.31458817

44.41678863 -1.351351063 -0.785 44.4 44.40693893 -1.012894174 44.71973609 -0.839570424 -2.399 44.9 44.96404342 -3.058396462 44.45856531

44.61795215 -1.512559036 -0.254 44.7 44.70072165 -0.325569829 44.83584578 -0.76405643 -1.159 44.8 44.81498947 -1.481941956 44.22316577

44.76373079 -1.32142198 -2.362 45.5 45.56126693 -2.971676037 45.00418452 -0.801321073 -1.836 45.1 45.13735588 -2.331197269 44.61173756

44.86045293 -1.119904293 -1.604 45.8 45.8280789 -2.0057835 45.38699034 -1.497440248 -1.419 45.3 45.32221929 -1.794175159 44.89873927

45.21199918 -1.24733524 0.148 44.9 44.90024392 0.188858456 45.10181909 -1.255954162 -0.951 46.3 46.30976572 -1.176687377 45.21296237

45.37789574 -1.21329093 -1.092 48.7 48.71224142 -1.284527892 45.68491529 -1.235265496 -2.349 47.2 47.25841513 -2.84908554 45.63446482

45.83508362 -1.423295629 -1.168 46.1 46.11479398 -1.451348297 45.9695578 -1.308341183 -1.552 45.8 45.82628835 -1.940808661 45.77817231

45.98406846 -1.314399808 -0.605 44.1 44.10414975 -0.785981229 45.87012915 -1.385076417 -0.355 46.6 46.60135218 -0.43647228 46.07589943

46.16880553 -1.389934208 0.421 46.1 46.10192231 0.523228908 45.96023838 -0.802592259 -1.14 45.7 45.71421661 -1.428963795 46.17204288

46.68523761 -1.225693349 -0.418 46.3 46.30188683 -0.5172567 46.03920637 -0.554504459 -0.79 46.5 46.50671027 -0.973318531 46.36945804

46.85216417 -1.237761519 -0.763 46.5 46.50625946 -0.940059289 46.30687563 -0.742657417 -0.517 47.8 47.80279583 -0.619681234 46.61829639

46.93505102 -1.217024477 -1.2466 46.4 46.41674279 -1.538959942 45.92429252 -0.785062758 -2.0666 48.1 48.14437491 -2.460180457 46.76595636

46.57108109 -1.289876158 -2.827 45.7 45.78735556 -3.53980381 45.86971945 -1.133138677 -0.77 46.2 46.20641622 -0.954841254 46.829311

46.54453147 -1.638768449 -1.802 46.3 46.33505373 -2.228831751 46.24153678 -1.373613764 -1.225 46.2 46.21623768 -1.518850397 46.76512525

46.3615153 -1.656238333 -2.635 47 47.07380615 -3.208861662 46.40351742 -1.995628859 -2.185 47.4 47.4503343 -2.639297818 47.0544782

46.11691725 -2.082386929 -2.535 46.6 46.66889998 -3.113772151 46.46468628 -2.428381434 -5.255 50.3 50.57375826 -5.964234837 47.73231953

45.88860612 -2.275704328 -3.677 48.6 48.73889955 -4.326666078 46.83679296 -2.992815899 -1.159 48.9 48.91373305 -1.357737791 47.91747574

46.18612712 -2.117264657 -2.213 47.3 47.35174093 -2.678713827 46.99262598 -3.18277488 -3.553 49.5 49.62734941 -4.105522771 48.16463815

46.6069711 -2.183620976 -3.868 49.1 49.25212101 -4.504344574 47.57008689 -3.343531674 -2.218 48.6 48.65058606 -2.613043614 48.57199979

47.025252 -2.216683154 -1.705 46.8 46.83104766 -2.086455527 47.65275254 -3.319802303 -1.365 48 48.01940467 -1.628909729 48.87252763

Technical data presentation

Encoding data and markers

2 D - scatter plot 2 D – connected line plot

Plots

Regression line graph Mean and standard deviation

Plots

Bar graph (horizontal) Composite bar graph

Plots

Histogram (distribution of image) 3D – scatter plot

Plots

Think practical …

…when approaching a design problem

• Case Study - Introduction

Design a Catapult

• You are an engineer (that is good to know and even

better to start imagining being one)

• Your kid brother or sister is asking you to make a

catapult for them for playing during the winter season

• What are the things that you should know to design and

manufacture this catapult

Needs or Functionality

• What you are going to throw with that

• How fast you want to throw a particular object

• How far your catapult should be able to throw that

• What will be mechanism of working of the catapult that you

designed

• How are you going to design that

• After the design, how are you going to produce that

Preliminary Design Constraints

• The part you are going to throw with your design is “assume

an Eraser that you use in drawing class”

• You have to throw that to a distance of say 10 meters

• Since you are designing this for your kid brother or sister,

you cannot use unsafe mechanisms like

• Things that give out lot of energy or sound like explosive materials

etc

• Or use of gasoline or heat to power the device

Design Requirement

• Since you should be able to do it easily you have think of

following things

• Use minimum number of parts in the assembly (<15)

• Use power sources like spring, air cylinder, rubber band or the likes

of these

• The geometric parameters of the components catapult will have an

effect on its performance

• Try mostly to use standard parts in your design

What Have You to Do?

• Come to the next class with a piece of paper outlining the

design including the following

• The components and their sizes and specs

• What were your considerations to choose those particular dimensions

and sizes

• 2 or 3 lines about the mechanism of operation

• We will discuss all those designs and I will show one of the design

myself.

Basic welding symbols

Working drawing of a compression spring

Spring representation

Detailed representation

Sch

emat

ic r

epre

sen

tati

on

Roller-type followers stud and bore

Cams

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