Chapter 21 Production Control

7/23/2019 Chapter 21 Production Control

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IT 208 Chapter 21 1

Production Control

Chapter 21



IT 208 Chapter 21 2

Competencies Describe the difference between Jigs and Fixtures

Describe the difference between CAD/CAM

Define c!puter integrated !anufacturing

"ist essentia# c!pnents f rbtics and describetheir functin

Describe the disad$antage f Just%in%ti!e schedu#ing



IT 208 Chapter 21 &

CHARACTERISTICS OF

DIFFERENT TYPES OF FACILITIES

The !st i!prtant factr in !anufacturing is the rate fprductin' because it deter!ines which !anufacturing

prcesses wi## be the !st efficient fr an( gi$enprduct) This s(ste! is dri$en b( the cust!ers*de!and +,u## s(ste!-



IT 208 Chapter 21 .

Characteristics O

Dierent T!pes O Facilities

,iecewr ,rductin

!a## atch ,rductin +1%20 ,arts/r)-

"arge atch 3r Cntinuus ,rcesses +20%200,arts/r)-

Mass ,rductin +3$er 200 ,arts/r-



IT 208 Chapter 21 4

Piece"or# Production Defined as the fabricatin f ne c!p#ete unit at a

ti!e)

5ti#i6atin f e7uip!ent is nt a great cncern since

the e7uip!ent is nt usua##( shared r tied upcntinuus#( fr the prductin run)

,iecewr faci#ities are ften batch prcesses inwhich prducts are !ade indi$idua##()



IT 208 Chapter 21

Piece"or# Production1) Jigs and Fixtures

a- A fixture is a de$ice that is indi$idua##( designed t h#d aspecific wrpiece in p#ace) Its specific 9b is t faci#itatesetup r t !ae h#ding easier)

: ;x) % 5se a fixture t h#d a particu#ar p#ug at an ang#e freasier s#dering)

b- A jig is a fixture that estab#ishes certain critica# #catindi!ensins n the wrpiece)

: ;x) < 5sing a 9ig fr the h#ding and dri##ing precise h#es

+int a casting- fr the shafts f a three di!ensina#!echanis!)

c) Work holder is the genera# ter! fr either a 9ig r afixture) A !iter bx r a bench $ise !ight be a wrh#der)


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Piece"or# Production2. Inspection is the act f deter!ining whether r nt

the si6e' shape' and #catin f a## features f thewrpiece are cnsistent with the drawings r

ther specificatins) Inspectins are perfr!ed b(!achinists r peratrs)


http://slidepdf.com/reader/full/chapter-21-production-control 8/24IT 208 Chapter 21 8

Small $atch Production

%&'() Parts*Hr+, At this rate f prductin' c!p#eted parts begin t

tae up a significant a!unt f space befre the(can be shipped and raw !ateria#s are needed at a

faster rate than the( are with piecewr) red! bec!es a cncern and nt n#( affects

the 7ua#it( f the prduct' but safet( is a#saffected)


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%&'() Parts*Hr+,?u!erica# Cntr# is a wa( f cntr##ing the actin f

!achines b( gi$ing the! a set f instructins innu!erica# fr!)

C!puteri6ed ?u!erica# Cntr#: Can be prgra!!ed t cntr# se$era# prductin

!achines

: Can stre prgra!s and data that wu#d a##w it ttrac the wear f the cutting t#s and aut!atica##(

c!pensate fr that wear): Machines were designed with a t# carrier s that

t#s cu#d be changed b( c!puter cntr#)



IT 208 Chapter 21 10


%&'() Parts*Hr+,!e ,rb#e!s f C?C

: ?ew !achines are $er( expensi$e and n#( 4@ fthe part*s tta# !anufacturing ti!e is it actua##( n

the !achine): 3n#( prfitab#e if it frees up ti!e t super$ise !re

!achines r t spend ti!e with the hu!an acti$ities

that c!puters cannt d we##




Lar-e $atch Or Continuous Processes

%()'()) parts*hr+, ? #nger des ne persn see the part fr! start

t finish)

chedu#ing is an i!prtant part f this t(pe f

!anufacturing) Inspect the parts fre7uent#( t detect trends in

parts nt !eeting standards and tae crrecti$eactin befre the parts are s far fr! the

specificatins that the( are scrap)





%()'()) parts*hr+,

&) C!puter%Aided Drafting/ C!puter%Aut!atedManufacturing

a- C!puter%Aided Drafting is a !ethd f drafting that uses

a c!puter t draw n the screen as instructed b( an peratr)The c!puter acts n#( as an e#ectrnic drafting bardB it desnt d an(thing n its wn)



IT 208 Chapter 21 1&


%()'()) parts*hr+,

b- C!puter Aut!ated ;ngineering +CA;- is a s(ste!that uses a c!puter t !ae design drawings' but additina##( iscapab#e f ding engineering ana#(sis f the designed b9ect)

: Deter!ine the $#u!e and weight f the part and #cate itscenter f !ass)

: D a c!p#ete structura# ana#(sis f the prduct)

: Deter!ine c#earances and a##wances between !atchingparts)

: De$ise the pti!u! steps fr the !anufacture f the prduct)

: Create the c!!ands fr the c!puter cntr##ed !achines

that !ae the prduct): eep the in$entr( recrds and ther dcu!entatin fr the

prduct



IT 208 Chapter 21 1.


%()'()) parts*hr+,

c- C!puter%Aut!ated Manufacturing is an appracht rgani6ing a !anufacturing p#ant s that a## pssib#eana#(ses' decisins' and actins are assigned t a !asterc!puter)

d-T(pica# C!puter 3peratins in CAM : Cntr# the in$entr()

: Direct the transprtatin f raw !ateria#s' c!p#etedprducts' and parts at different stages during!anufacture)

:Create !achine !aintenance schedu#es)

: Cntr# the aut!atic inspectin

: Maintain dcu!entatin

: Cntr# the actins f rbts)





%()'()) parts*hr+,

EbticsEbts ha$e fi$e essentia# c!pnents

1) Manipulator % the part f the !achine that actua##(

hand#es the t#' !ateria#' r part)2) Actuators % respnd t the signa#s fr! the cntr##er'causing the !anipu#atr t perfr! its assigned functin)

3) Sensors % detect the psitins f the $arius c!pnentsf the ar! and hand and feed data bac t the cntr##er)

) !ontrollers % c!puters that send cntr# signa#s t the

!anipu#atrs and respnd t the data fed bac t the! b(the sensrs)") #o$er supplies % pr$ide the energ( that dri$es the

cntr##ers' sensrs' !anipu#atrs' and actuatrs)



IT 208 Chapter 21 1


%()'()) parts*hr+,

5se f Ebts

Manipu#atrs

: The rbt !anipu#atr !ust dup#icate essentia##( e$er(

!$e!ent f the hu!an ar! and hand) Actuatrs

: The !usc#esB f the rbt !echanis!) These !a( bepwered b( air' h(drau#ic f#uid' e#ectricit(' !agnetis!' r a

$acuu!)



IT 208 Chapter 21 1=


%()'()) parts*hr+,

: Air%perated and $acuu!%perated +pneu!atic-!echanis!s are usua##( s!a## and #i!ited b( thea!unt f frce the( can exert' but the( are inexpensi$et cnstruct and perate)

: (drau#ic !echanis!s are capab#e f exerting #argefrces' are high pwered' and are a!a6ing#( 7uic frtheir si6e) The( d tend t be !ess( due t theine$itab#e #eaage f h(drau#ic f#uid)

: ;#ectrica##( dri$en !echanis!s are apprpriate fr #ight

dut() The( are $er( accurate' precise' and c#ean): Magnetica##( dri$en actuatrs such as s#enids are$er( 7uic but are #i!ited b( the a!unt f frce the(can exert n the wrpiece)





%()'()) parts*hr+,

C!puter Functins

: The brainB f the rbt is the c!puter that cntr#s therbt)

Cntr# (ste! Functins: If the c!puter is the GbrainB f the rbtics s(ste!' then

the cntr# s(ste! is its ner$us s(ste!)B

Ebt Functins

: Thrugh its end%f%ar! de$ice +handB-' the rbt eitherpics up the wrpiece r des s!ething with it)



IT 208 Chapter 21 1>

.ualit! Assurance Throu-h

Automated Inspection

%ualit& !ontrol +HC-: Cncerned with ensuring that the prducts !eet their

design standards

: Causes f ,rduct ariatin

: Inherent 'ariation is the una$idab#e $ariatin in thedi!ensins f a part due t such causes as f#exure f thecutting t#' etc)

: Assignable !ause is an act r acti$it( that can be identifiedas the reasn wh( a wrpiece de$iates)

: A !anufacturing prcess is said t be in controlB when the

assignab#e causes ha$e been detected and crrected s thatn#( the inherent $ariatin is #eft)




.ualit! Assurance Throu-h

Automated Inspection

Statistical %ualit& !ontrol

: the cntr# f the 7ua#it( f the parts prduced b( anana#(sis f the nu!erica# data deri$ed fr!

!easure!ents taen n thse parts) Meeting (ra$ing olerances

: If the designer ass fr t#erances that are s!a##erthan can be achie$ed with a !achine' then either the

t#erances need t be #senedB r e#se the prcessneeds t be dne n a different !achine)




/ust'in'Time Sche ulin-

A t(pe f prductin rgani6atin in which the !ateria# fra part r asse!b#( is de#i$ered 9ust in ti!e t beused)

: hifts respnsibi#it( fr 7ua#it( t the supp#iers: Eeduce prductin csts b( 20@ t .0@)

: The drawbac t JIT is that the prductin #ine is shutdwn if e$en ne part des nt c!e in 9ust in ti!e)B




0ass Production %o1er ()) parts*hr,

Cnstant#( fcused n reducing fractina# csts)+a$ing )20/pc K &00 pcs)/hr) L 00'000/(r)

1) Adapti$e Cntr#: A t(pe f feedbac cntr# that senses changes utside f

the feedbac #p +te!perature' pressure' $ibratin' etc)-and changes the instructins +t the actuatrs- s that thedesired resu#t is sti## acc!p#ished in spite f the exterir

change)



IT 208 Chapter 21 2&


2) Ce##u#ar 3rgani6atin

: is a wa( f rgani6ing a !anufacturing faci#it( s that!st f the prcesses are carried ut b( a s!a## grup f

!achines +the ce##B-) ;x) < C!bining turning' !i##ing'and dri##ing peratins in a !achining center)

&) F#exib#e Manufacturing (ste!s +FM-

: sa!e cncept as that f the !achining ce## except thatthe e#e!ents f the FM are !achining ce##s rather than

!achining centers) Fig) 21%&.



IT 208 Chapter 21 2.


.) C!puter%Integrated Manufacturing

: CIM is a !ethd#g( and a ga# it is nt a c##ectin fe7uip!ent and sftware)

: Its !ethd is t integrate a## aspects f design' p#anning'!anufacturing' distributin' and !anage!ent)

: Its ga# is t transfr! prduct designs and !ateria#s intsa#eab#e gds at a !ini!u! cst in the shrtest pssib#eti!e)

: CIM treats !anufacturing prcesses and p#ant peratinsand their !anage!ent as a sing#e s(ste!' nt ase7uentia# acti$it()

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Chapter 21 Production Control

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