computer aided design lecture notes pdf and computer aided design and manufacturing lecture notes and computer aided design guide for architecture engineering and construction pdf
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ME 6501 - CAD III/ V MECHANICAL ENGINEERING
An e-Course Material on
ME 6501 – COMPUTER AIDED DESIGN
ME 6501 – COMPUTER AIDED DESIGN
By
Mr. A. MAHENDRAN, M.E., PGDPC., MISTE.,
ASSISTANT PROFESSOR
DEPARTMENT OF MECHANICAL ENGINEERING
SASURIE COLLEGE OF ENGINEERING
VIJAYAMANGALAM – 638 056
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UNIT - I
F F FU U UN N ND D DA A AM M ME E EN N NT T TA A AL L LS S S O O OF F F C C CO O OM M MP P PU U UT T TE E ER R R G G GR R RA A AP P PH H HI I IC C CS S S
1. PRE-R RE EQ QU UI IS SI IT TE E D DI IS SC CU US SS SI IO ON N
1.1. P PR RO OD DU UC CT T L LI IF FE E C CY YC CL LE E ( (P PL LC C) )
E E Ev v ve e er r ry y y p p pr r ro o od d du u uc c ct t t g g go o oe e es s s t t th h hr r ro o ou u ug g gh h h a a a c c cy y yc c cl l le e e f f fr r ro o om m m b b bi i ir r rt t th h h,,, f f fo o ol l ll l lo o ow w we e ed d d b b by y y a a an n n i i in n ni i it t ti i ia a al l l g g gr r ro o ow w wt t th h h s s st t ta a ag g ge e e,,, a a a
r r re e el l la a at t ti i iv v ve e el l ly y y s s st t ta a ab b bl l le e e m m ma a at t tu u ur r re e ed d d p p pe e er r ri i io o od d d,,, a a an n nd d d f f fi i in n na a al l ll l ly y y i i in n nt t to o o a a a d d de e ec c cl l li i in n ni i in n ng g g s s st t ta a ag g ge e e t t th h ha a at t t e e ev v ve e en n nt t tu u ua a al l ll l ly y y e e en n nd d ds s s i i in n n
t th he e d de ea at th h o of f t th he e p pr ro od du uc ct t a as s s sh ho ow wn n s sc ch he em ma at ti ic ca al ll ly y i in n Figure.
Figure.1.1. Product Life Cycle
(1) Introduction stage: : I In n t th hi is s s st ta ag ge e t th he e p pr ro od du uc ct t i is s n ne ew w a an nd d t th he e c cu us st to om me er r a ac cc ce ep pt ta an nc ce e i is s l lo ow w a an nd d
hence the sales are low.
(2) Growth stage: : : K K Kn n no o ow w wl l le e ed d dg g ge e e o o of f f t t th h he e e p p pr r ro o od d du u uc c ct t t a a an n nd d d i i it t ts s s c c ca a ap p pa a ab b bi i il l li i it t ti i ie e es s s r r re e ea a ac c ch h he e es s s t t to o o a a a g g gr r ro o ow w wi i in n ng g g n n nu u um m mb b be e er r r o o of f f
customers.
(3) Maturity stage: : : T T Th h he e e p p pr r ro o od d du u uc c ct t t i i is s s w w wi i id d de e el l ly y y a a ac c cc c ce e ep p pt t ta a ab b bl l le e e a a an n nd d d s s sa a al l le e es s s a a ar r re e e n n no o ow w w s s st t ta a ab b bl l le e e,,, a a an n nd d d i i it t t g g gr r ro o ow w ws s s w w wi i it t th h h
t th he e s sa am me e r ra at te e a as s t th he e e ec co on no om my y a as s a a w wh ho ol le e g gr ro ow ws s..
(4) Decline stage: : : A A At t t s s so o om m me e e p p po o oi i in n nt t t o o of f f t t ti i im m me e e t t th h he e e p p pr r ro o od d du u uc c ct t t e e en n nt t te e er r rs s s t t th h he e e d d de e ec c cl l li i in n ne e e s s st t ta a ag g ge e e... I I It t ts s s s s sa a al l le e es s s s s st t ta a ar r rt t t
d d de e ec c cr r re e ea a as s si i in n ng g g b b be e ec c ca a au u us s se e e o o of f f a a a n n ne e ew w w a a an n nd d d a a a b b be e et t tt t te e er r r p p pr r ro o od d du u uc c ct t t h h ha a as s s e e en n nt t te e er r re e ed d d t t th h he e e m m ma a ar r rk k ke e et t t t t to o o f f fu u ul l lf f fi i il l ll l l t t th h he e e s s sa a am m me e e
customer requirements.
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1.2. P P PR R RO O OD D DU U UC C CT T T L L LI I IF F FE E E C C CY Y YC C CL L LE E E ( ( (P P PL L LC C C) ) ) F F FO O OR R R C C CO O ON N NT T TI I IN N NU U UO O OU U US S S I I IM M MP P PR R RO O OV V VE E EM M ME E EN N NT T T
F F Fi i ig g gu u ur r re e e...1 1 1...2 2 2... P P Pr r ro o od d du u uc c ct t t L L Li i if f fe e e C C Cy y yc c cl l le e e f f fo o or r r c c co o on n nt t ti i in n nu u uo o ou u us s s I I Im m mp p pr r ro o ov v ve e em m me e en n nt t t ( ( (B B Ba a as s si i ic c c) ) )
F F Fi i ig g gu u ur r re e e...1 1 1...3 3 3... P P Pr r ro o od d du u uc c ct t t L L Li i if f fe e e C C Cy y yc c cl l le e e f f fo o or r r c c co o on n nt t ti i in n nu u uo o ou u us s s I I Im m mp p pr r ro o ov v ve e em m me e en n nt t t ( ( (D D De e et t ta a ai i il l le e ed d d) ) )
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1.3. TECHNOLOGY DEVELOPMENT CYCLE
The development of a new technology follows a typical S-shaped curve. In its early
stage, the progress is limited by the lack of ideas. A single good idea can make several
other god ideas possible, and the rate of progress is exponential. Gradually the growth
becomes linear when the fundamental ideas are in place and the progress is concerned
with filling the gaps between, the key ideas.
It is during this time when the commercial exploitation flourishes. But with time the
technology begins to run dry and increased improvements come with greater difficulty.
This matured technology grows slowly and approaches a limit asymptotically.
The success of a technology based company lies in its capabilities of recognizing when
the core technology on which the company’s products are based begin to mature and
through an active R&D program, transfer to another technology growth curve which
offers greater possibilities.
Figure.1.4. Schematic outline of Technology Development Curve
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Figure.1.5. Improved program to develop new technology before the complete extinct of
existing technology
1.4. THE DESIGN PROCESS - INTRODUCTION
The Engineering Design Process is the formulation of a plan to help an engineer build a
product with a specified performance goal. This process involves a number of steps, and
parts of the process may need to be repeated many times before production of a final
product can begin.
It is a decision making process (often iterative) in which the basic sciences, mathematics,
and engineering sciences are applied to convert resources optimally to meet a stated
objective. Among the fundamental elements of the design process are the establishment of
objectives and criteria, synthesis, analysis, construction, testing and evaluation.
The Engineering Design process is a multi-step process including the research,
conceptualization, feasibility assessment, establishing design requirements, preliminary
design, detailed design, production planning and tool design, and finally production.
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1 1..4 4..1 1.. S St te ep ps s i in nv vo ol lv ve ed d i in n E En ng gi in ne ee er ri in ng g D De es si ig gn n p pr ro oc ce es ss
F Fi ig gu ur re e..1 1..6 6.. E En ng gi in ne ee er ri in ng g D De es si ig gn n P Pr ro oc ce es ss s
Conceptual Design
I I It t t i i is s s a a a p p pr r ro o oc c ce e es s ss s s i i in n n w w wh h hi i ic c ch h h w w we e e i i in n ni i it t ti i ia a at t te e e t t th h he e e d d de e es s si i ig g gn n n a a an n nd d d c c co o om m me e e u u up p p w w wi i it t th h h a a a n n nu u um m mb b be e er r r o o of f f d d de e es s si i ig g gn n n c c co o on n nc c ce e ep p pt t ts s s
a a an n nd d d t t th h he e en n n n n na a ar r rr r ro o ow w w d d do o ow w wn n n t t to o o t t th h he e e s s si i in n ng g gl l le e e b b be e es s st t t c c co o on n nc c ce e ep p pt t t... T T Th h hi i is s s i i in n nv v vo o ol l lv v ve e ed d d t t th h he e e f f fo o ol l ll l lo o ow w wi i in n ng g g s s st t te e ep p ps s s...
(1) Identification o of f c cu us st to om me er r n ne ee ed ds s: : T Th he e m ma ai il l o ob bj je ec ct ti iv ve e o of f t th hi is s i is s t to o c co om mp pl le et te el ly y u un nd de er rs st ta an nd d t th he e
c cu us st to om me er rs s’ ’ n ne ee ed ds s a an nd d t to o c co om mm mu un ni ic ca at te e t th he em m t to o t th he e d de es si ig gn n t te ea am m
(2) Problem definition: : : T T Th h he e e m m ma a ai i il l l g g go o oa a al l l o o of f f t t th h hi i is s s a a ac c ct t ti i iv v vi i it t ty y y i i is s s t t to o o c c cr r re e ea a at t te e e a a a s s st t ta a at t te e em m me e en n nt t t t t th h ha a at t t d d de e es s sc c cr r ri i ib b be e es s s w w wh h ha a at t t
all needs to be ac c cc c co o om m mp p pl l li i is s sh h he e ed d d t t to o o m m me e ee e et t t t t th h he e e n n ne e ee e ed d ds s s o o of f f t t th h he e e c c cu u us s st t to o om m me e er r rs s s’ ’ ’ r r re e eq q qu u ui i ir r re e em m me e en n nt t ts s s...
(3) Gathering Information: : : I I In n n t t th h hi i is s s s s st t te e ep p p,,, w w we e e c c co o ol l ll l le e ec c ct t t a a al l ll l l t t th h he e e i i in n nf f fo o or r rm m ma a at t ti i io o on n n t t th h ha a at t t c c ca a an n n b b be e e h h he e el l lp p pf f fu u ul l l f f fo o or r r
d de ev ve el lo op pi in ng g a an nd d t tr ra an ns sl la at ti in ng g t th he e c cu us st to om me er rs s’ ’ n ne ee ed ds s i in nt to o e en ng gi in ne ee er ri in ng g d de es si ig gn n..
(4) Conceptualization: I I In n n t t th h hi i is s s s s st t te e ep p p,,, b b br r ro o oa a ad d d s s se e et t ts s s o o of f f c c co o on n nc c ce e ep p pt t ts s s a a ar r re e e g g ge e en n ne e er r ra a at t te e ed d d t t th h ha a at t t c c ca a an n n p p po o ot t te e en n nt t ti i ia a al l ll l ly y y
s sa at ti is sf fy y t th he e p pr ro ob bl le em m s st ta at te em me en nt t
(5) Concept selection: : : T T Th h he e e m m ma a ai i in n n o o ob b bj j je e ec c ct t ti i iv v ve e e o o of f f t t th h hi i is s s s s st t te e ep p p i i is s s t t to o o e e ev v va a al l lu u ua a at t te e e t t th h he e e v v va a ar r ri i io o ou u us s s d d de e es s si i ig g gn n n
c co on nc ce ep pt ts s,, m mo od di if fy yi in ng g a an nd d e ev vo ol lv vi in ng g i in nt to o a a s si in ng gl le e p pr re ef fe er rr re ed d c co on nc ce ept.
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Embodiment Design
It is a process where the structured development of the design concepts takes place. It is in
this phase that decisions are made on strength, material selection, size shape and spatial
compatibility. Embodiment design is concerned with three major tasks – product architecture,
configuration design, and parametric design.
(1) Product architecture: It is concerned with dividing the overall design system into small
subsystems and modules. It is in this step we decide how the physical components of the
design are to be arranged in order to combine them to carry out the functional duties of the
design.
(2) Configuration design: In this process we determine what all features are required in the
various parts / components and how these features are to be arranged in space relative to
each other.
(3) Parametric design: It starts with information from the configuration design process and
aims to establish the exact dimensions and tolerances of the product. Also, final decisions
on the material and manufacturing processes are done if it has not been fixed in the
previous process. One of the important aspects of parametric designs is to examine if the
design is robust or not.
Detail Design
It is in this phase the design is brought to a state where it has the complete engineering
description of a tested and a producible product. Any missing information about the arrangement,
form, material, manufacturing process, dimensions, tolerances etc of each part is added and detailed
engineering drawing suitable for manufacturing are prepared.
1.4.2. Models of the Design Process
Designers have to:
Explore - the problem ‘territory’
Generate - solution concepts
Evaluate - alternative solution concepts
Communicate - a final proposal
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A simple model of the design process, derived from what designers have to do
French’s model VDI model
Cross’s basic model
1.4.3. New Design Procedures
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1 1..4 4..4 4.. N Ne ee ed d f fo or r A Ap pp pl ly yi in ng g T Te ec ch hn no ol lo og gy y i in n t th he e D De es si ig gn n P Pr ro oc ce es ss s
D De es si ig gn n i is s t th he e e es ss se en nc ce e o of f e en ng gi in ne eering
S St ta ar rt ts s w wi it th h r re ec co og gn ni it ti io on n o of f s so om me e n ne ee ed d
P Pr ro og gr re es ss se es s t to o p ph hy ys si ic ca al l i im mp pl le em me en nt ta at ti io on n
R Re es su ul lt ts s m ma ay y b be e s si im mp pl le e o or r c co om mp pl le ex x
D De es si ig gn n c ca an n b be e o of f t tw wo o k ki in nd d: :
o S So om me et th hi in ng g c co om mp pl le et te el ly y n ne ew w ,, o or r
o A An n i im mp pr ro ov ve ed d f fo or rm m o of f s so om me et th hi in ng g a al lr re ea ad dy y i in n e ex xi is st te en nc ce e
1.5. M MO OR RP PH HO OL LO OG GY Y O OF F D DE ES SI IG GN N
The consider r ra a at t ti i io o on n n o o of f f t t th h he e e p p pr r ro o od d du u uc c ct t t l l li i if f fe e e f f fr r ro o om m m i i it t ts s s c c co o on n nc c ce e ep p pt t ti i io o on n n t t to o o r r re e et t ti i ir r re e em m me e en n nt t t...............
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Anatomy of Design
D D De e et t ta a ai i il l le e ed d d e e ex x xa a am m mi i in n na a at t ti i io o on n n o o of f f t t th h he e e e e en n ng g gi i in n ne e ee e er r r’ ’ ’s s s a a ac c ct t ti i io o on n ns s s a a as s s h h he e e/ / /s s sh h he e e i i id d de e en n nt t ti i if f fi i ie e es s s a a an n nd d d s s so o ol l lv v ve e es s s t t th h he e e p p pr r ro o ob b bl l le e em m m: : :
1.5.1. Needs Analysis
C Cr re ea at ti io on n b be eg gi in ns s b by y r re ec co og gn ni iz zi in ng g a a n ne ee ed d
o A Ap pp pa ar re en nt t f fr ro om m o ob bs se ervation
o R Re es su ul lt ts s o of f a a d de et ta ai il le ed d s st tu ud dy y
o A A s sp pe ec ci if fi ic c s se et t o of f c ci ir rc cu um ms st ta an nc ce es s
R Re es su ul lt ts s i in n a a p pr ri im mi it ti iv ve e s st ta at te em me en nt t
o F Fa ac ct t o or r o op pi in ni io on n
o D Do oe es s t th he e n ne ee ed d e ex xi is st t a an nd d i is s i it t r re ea al li is st ti ic c? ?
o D Do oe es s i it t e ex xi is st t n no ow w o or r w wi il ll l i it t e ex xi is st t i in n t th he e f fu ut tu ur re e? ?
o I Is s i it t a a n ne ew w n ne ee ed d? ? ( (n ne ew w m ma at te er ri ia al l o or r p ph hy ys si ic ca al l p pr ri inciple)
O Of ft te en n d de ep pe en nd ds s o on n c ci ir rc cu um ms st ta an nc ce es s
N N Ne e ee e ed d ds s s a a an n na a al l ly y ys s si i is s s o o on n nc c ce e e t t th h hr r ro o ou u ug g gh h h t t th h he e e A A An n na a at t to o om m my y y p p pr r ro o ov v vi i id d de e es s s a a a g g go o oo o od d d s s st t ta a ar r rt t ti i in n ng g g p p po o oi i in n nt t t f f fo o or r r t t th h he e e
Feasibility Study
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1.5.2. Feasibility Study
Designs can be futile unless satisfying the original need is feasible
At this stage, the product appears in abstract forms, but is they feasible???
Alternative solutions must be subjected to physical and economic analyses and be realizable
from both
The Feasibility Study using analysis of several alternatives establishes the design concept as
something which can be realised and accepted
Some examples.....
(i) A building must be comfortable to live in:
Heating, ventilation and air conditioning are required. Specify limits of temperature,
humidity, velocity and fresh air constituency.
(ii) National fossil fuel supplies are low:
Alternative forms of energy supply are required. Specify amount and where they are
needed, and any restrictions of space, time or pollution levels.
1.5.3. Preliminary Design
Main purpose is selection of the best possible solution from a choice of alternatives
Make comparisons against given criteria & constraints
Must maintain an open mind; use your judgement.
1.5.4. Detailed design
Aim is to produce a complete set of working drawings which are then transmitted to the
manufacturer
This stage of design is far less flexible than those previous
Design should now reflect all of the planning both for manufacture and consumption stages
Construction/testing of various components may be required
Prototype building ....is it what was expected?
1.5.5. Production
Here, the device or system is actually constructed, and planning for this should have been
incorporated into the design
Knowledge of the capability of the machines is required, since it must be possible to build
and assemble the components as specified
Special jigs, fixtures and even machines may be required
Planning is vital; including quality control hold points, methods of inspection, standards for
comparison etc...
Timing of construction may be important eg. Climatics
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1.5.6. Distribution
Transport t ta a at t ti i io o on n n o o of f f t t th h he e e m m ma a an n nu u uf f fa a ac c ct t tu u ur r re e ed d d a a ar r rt t ti i ic c cl l le e e,,, c c co o om m mp p pl l le e et t te e e o o or r r i i in n n s s su u ub b ba a as s ss s se e em m mb b bl l ly y y f f fo o or r rm m m m m mu u us s st t t b b be e e
anticipated in the design
P P Pa a ac c ck k ka a ag g gi i in n ng g g,,, a a av v va a ai i il l la a ab b bi i il l li i it t ty y y o o of f f v v ve e eh h hi i ic c cl l le e es s s,,, r r re e eg g gu u ul l la a at t ti i io o on n ns s s f f fo o or r r u u us s se e e o o of f f t t th h ho o or r ro o ou u ug g gh h hf f fa a ar r re e es s s,,, s s sh h he e el l lf f f/ / /c c co o om m mp p po o on n ne e en n nt t t
l li if fe e,, w wa ar re eh ho ou us se e s st to or ra ag ge e f fa ac ci il li it ti ie es s,, s sp pe ec ci ia al l h ha an nd dl li in ng g,, e en nv vi ir ro on nm me en nt ta al l c co on nt tr ro ol l o of f t te em mp pe er ra at tu ur re e
a an nd d h hu um mi id di it ty y m ma ay y n ne ee ed d t to o b be e a ad dd dr re es ss se ed d
1.5.7. Consumption
T Th he e p pr ro od du uc ct t i is s n no ow w u us se ed d b by y t th he e c co on ns su um me er r
I If f t th he e d de es si ig gn n i is s e ef ff fe ec ct t,, i it t w wi il ll l h ha av ve e m me et t t th he e n ne ee ed d
T T Th h he e e d d de e es s si i ig g gn n n m m ma a ay y y y y ye e et t t n n no o ot t t b b be e e c c co o om m mp p pl l le e et t te e e; ; ; r r re e ed d de e es s si i ig g gn n ns s s a a an n nd d d m m mo o od d di i if f fi i ic c ca a at t ti i io o on n ns s s m m ma a ay y y b b be e e r r re e eq q qu u ui i ir r re e ed d d
depend di in ng g o on n f fi ie el ld d t tr ri ia al ls s o or r c co on ns su um me er r f fe ee ed db ba ac ck k
M M Ma a ay y y n n ne e ee e ed d d t t to o o c c co o on n ns s si i id d de e er r r m m ma a ai i in n nt t te e en n na a an n nc c ce e e o o of f f c c co o om m mp p po o on n ne e en n nt t ts s s a a an n nd d d s s su u up p pp p pl l ly y y o o of f f s s sp p pa a ar r re e e p p pa a ar r rt t ts s s o o or r r
subassemblies
1.5.8. Retirement
T Th he e p pr ro od du uc ct t w wi il ll l b be e d di is sc ca ar rd de ed d a as s i it ts s l li if fe e c cy yc cl le e t te er rm mi in na at te es s
I It t m ma ay y h ha av ve e b be ec co om me e o ob bs so ol le et te e w wh hi il ls st t s st ti il ll l s se er rv vi ic ce ea ab bl le e a an nd d t th he er re ef fo or re e t th he e d de es si ig gn n m ma ay y n no ot t h ha av ve e
been fully economical
D D Di i is s sp p po o os s sa a al l l a a an n nd d d r r re e ec c co o ov v ve e er r ry y y o o of f f u u us s se e ef f fu u ul l l m m ma a at t te e er r ri i ia a al l ls s s s s sh h ho o ou u ul l ld d d h h ha a av v ve e e b b be e ee e en n n i i in n nc c cl l lu u ud d de e ed d d i i in n n t t th h he e e d d de e es s si i ig g gn n n
T Th hr re ea at ts s t to o s sa af fe et ty y s sh ho ou ul ld d b be e g gu ua ar rd de ed d a ag ga ai in ns st t
1.6. D DE ES SI IG GN N P PR RO OC CE ES SS S M MO OD DE EL LS S
1.6.1. Shigley Model
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1.6.2. Ohsuga Model
1.6.3. Earle Model
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1.7. S SE EQ QU UE EN NT TI IA AL L E EN NG GI IN NE EE ER RI IN NG G D DE ES SI IG GN N
1.8. C CO ON NC CU UR RR RE EN NT T E EN NG GI IN NE EE ER RI IN NG G D DE ES SI IG GN N
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SEQUENTIAL AND CONCURRENT ENGINEERING
With today's marketplace becoming more and more competitive, there is an ever-increasing
pressure on companies to respond quickly to market needs, be cost effective, reduce lead-times to
market and deliver superior quality products.
Traditionally, design has been carried out as a sequential set of activities with distinct non-
overlapping phases. In such an approach, the life-cycle of a product starts with the identification of
the need for that product. These needs are converted into product requirements which are passed on
to the design department. The designers design the product's form, fit, and function to meet all the
requirements, and pass on the design to the manufacturing department.
After the product is manufactured it goes through the phases of assembly, testing, and
installation. This type of approach to life-cycle development is also known as `over the wall'
approach, because the different life-cycle phases are hidden or isolated from each other. Each phase
receives the output of the preceding phase as if the output had been thrown over the wall. In such
an approach, the manufacturing department, for example, does not know what it will actually be
manufacturing until the detailed design of the product is over.
Figure.1.8.Over the Wall Engineering (Sequential Engineering)
There are a lot of disadvantages of the sequential engineering process. The designers are
responsible for creating a design that meets all the specified requirements. They are usually not
concerned with how the product will be manufactured or assembled. Problems and inconsistencies
in the designs are therefore, detected when the product reaches into the later phases of its life-cycle.
At this stage, the only possible option is to send the product back for a re-design. The whole
process becomes iterative and it not until after a lot of re-designs has taken place that the product is
finally manufactured. Because of the large number of changes, and hence iterations, the product's
introduction to market gets delayed. In addition, each re-design, re-work, re-assembly etc. incurs
cost, and therefore the resulting product is costlier than what it was originally thought to be. The
market share is lost because of the delay in product's introduction to market, and customer faith is
lost. All this is undesirable.
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Concurrent Engineering is a dramatically different approach to product development in
which various life-cycle aspects are considered simultaneously right from the early stages of
design. These life-cycle aspects include product's functionality, manufacturability, testability,
assimilability, maintainability, and everything else that could be affected by the design.
In addition, various life-cycle phases overlap each other, and there in no "wall" between
these phases. The completion of a previous life-cycle phase is not a pre-requisite for the start of the
next life-cycle phase. In addition, there is a continuous feedback between these life-cycle phases so
that the conflicts are detected as soon as possible.
Figure.1.9. Concurrent Engineering
The concurrent approach results in less number of changes during the later phases of
product life-cycle, because of the fact that the life-cycle aspects are being considered all through
the design. The benefits achieved are reduced lead times to market, reduced cost, higher quality,
greater customer satisfaction, increased market share etc. Sequential engineering is the term used
to describe the method of production in a linear format. The different steps are done one after
another, with all attention and resources focused on that one task. After it is completed it is left
alone and everything is concentrated on the next task.
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In concurrent engineering, different tasks are tackled at the same time, and not necessarily
in the usual order. This means that info found out later in the process can be added to earlier parts,
improving them, and also saving a lot of time. Concurrent engineering is a method by which
several teams within an organization work simultaneously to develop new products and services
and allows a more stream lined approach. The concurrent engineering is a non-linear product or
project design approach during which all phases of manufacturing operate at the same time -
simultaneously. Both product and process design run in parallel and occur in the same time frame.
Product and process are closely coordinated to achieve optimal matching of requirements
for effective cost, quality, and delivery. Decision making involves full team participation and
involvement. The team often consists of product design engineers, manufacturing engineers,
marketing personnel, purchasing, finance, and suppliers.
Figure.1.9. Sequential and Concurrent Engineering
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ME 6501 - CAD III/ V M ME EC CH HA AN NI IC CA AL L E EN NG GI IN NE EE ER RI IN NG G
1.9. R RO OL LE E O OF F C CO OM MP PU UT TE ER RS S I IN N D DE ES SI IG GN N
1.10. C CA AD D S SY YS ST TE EM M A AR RC CH HI IT TE EC CT TU UR RE E
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ME 6501 - CAD III/ V M ME EC CH HA AN NI IC CA AL L E EN NG GI IN NE EE ER RI IN NG G
1.11. C CO OM MP PU UT TE ER R A AI ID DE ED D E EN NG GI IN NE EE ER RI IN NG G – CAD/CAM
1.12. A AP PP PL LI IC CA AT TI IO ON N O OF F C CO OM MP PU UT TE ER RS S T TO O D DE ES SI IG GN N
• M Mo od de el li in ng g o of f t th he e D De es si ig gn n
• E En ng gi in ne ee er ri in ng g d de es si ig gn n a an nd d a an na al ly ys si is s
• E Ev va al lu ua at ti io on n o of f P Pr ro ot to ot ty yp pe e t th hr ro ou ug gh h S Si im mu ul la at ti io on n a an nd d Testing
• D Dr ra af ft ti in ng g a an nd d D De es si ig gn n D Do oc cu um me en nt ta at ti io on n
1.13. BENEFITS OF CAD
1. P Pr ro od du uc ct ti iv vi it ty y I Im mp pr ro ov ve em me en nt t i in n D De es si ig gn n
D De ep pe en nd ds s o on n C Co om mp pl le ex xi it ty y o of f d dr ra aw wi in ng g,,
D De eg gr re ee e o of f r re ep pe et ti it ti iv ve en ne es ss s o of f f fe ea at tu ur re es s i in n t th he e d de es si ig gn ne ed d p pa ar rt ts s,,
D De eg gr re ee e o of f s sy ym mm me et tr ry y i in n t th he e p pa ar rt ts s,,
E Ex xt te en ns si iv ve e u us se e o of f l li ib br ra ar ry y o of f u us se er r d de ef fi in ne ed d s sh ha ap pe es s a an nd d c co om mm mo on nl ly y u us se ed d e en nt ti it ti ie es s
2. Shorter Lead Times
3. Flexibility in Design
4. Design Analysis
5. Fewer Design Error
6. S St ta an nd da ar rd di iz za at ti io on n o of f D De es si ig gn n,, D Dr ra af ft ti in ng g a an nd d D Do oc cu um me en nt ta at ti io on n
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7. Drawings are more understandable
8. Improved Procedures of Engineering Changes
9. Benefits in Manufacturing :
a. Tool and fixture design for manufacturing
b. Computer Aided process planning
c. Preparation of assembly lists and bill of materials
d. Computer aided inspection
e. Coding and classification of components
f. Production planning and control
g. Preparation of numerical control programs for manufacturing the parts on
CNC machines
h. Assembly sequence planning
1.14. REASONS FOR IMPLEMENTING CAD
• To increase the productivity of the designer
• To improve the Quality of Design
• To improve Documentation
• To create a Database for manufacturing
1.15. COMPUTER GRAPHICS or INTERACTIVE COMPUTER GRAPHICS
Computer Graphics is defined as creation, storage, and manipulation of pictures and
drawings by means of a digital computer
It is an extremely effective medium for communication between people and
computers
Computer graphics studies the manipulation of visual and geometric information
using computational techniques
It focuses on the mathematical and computational foundations of image generation
and processing rather than purely aesthetic issues
Concept of Interactive computer Graphics
In Interactive Computer Graphics (ICG) the user interacts with the compute and comprises the
following important functions:
26 A.MAHENDRAN - AP/MECH 2015-16
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