GD&T PPT GENERAL

7/21/2019 GD&T PPT GENERAL

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Imperial Automotive Industries

GeometricDimensioning and

Tolerancing

Mark A. Morris



2

Contact Information

John Lindland (734) 369-3120 President Cons!ltant "eminar Leader #!al"$%& Inc' JLindland!alsat'com

*ar+ $' *orris (734) ,7,-669

.e/resentin #!al"$%& Inc' mar+*and*cons!ltin'com



3

eometric Characteristic"mols

orm %olerances

Pro5le %olerances

rientation %olerances

.!no!t %olerances

Location %olerances



4

"ection 1

Background, History, and the

Importance of GD&T



nineerin 8rains

nineerin drains are the :ehicle!sed to comm!nicate re!irements forman!fact!red /arts' ra/hic .e/resentations ;ords <!mers "mols

nineerin drains are !sed tocomm!nicate contract!al re!irements'



6

;e <eed /erational8e5nitions

=;itho!t an o/erational de5nition&in:estiations of a /rolem ill e costl andine>ecti:e& almost certain to lead to endlessic+erin and contro:ers'?

;' dards 8emin& Ph'8'

/erational de5nitions /ro:ide three com/onents@

1' "/ecif %est to determine Com/liance

2' "et Criteria for J!dment

3' *a+e 8ecisions ased on the Criteria



7

rthora/hic andIsometric ProAection



,

rthora/hic andIsometric ProAection



9

1st :s' 3rd $nle ProAection

Third Angle ProjectionFirst Angle Projection

<ote@ %hird anle /roAection is more common in the

B"$& 5rst anle /roAection is more common in !ro/e'



10

I" :s' $"*

Comparing the ISO and the ASME Approaches to GD&T

Issue or Topic ISO ASME

Approach

Explanation

Cost o Standards

!"m#er o Standards

Theoretical F"nctional

Graphical$ Fe% ords

'(( ) *((( +SD

*( , *-

Comprehensi.e

/ *(( +SD

*

0ased on the %or1 o Alex 2"li1o%s1i$ *334



11

$"* 14'* 1994

"tr!ct!re1' "co/e& 8e5nitions& and eneral 8imensionin

2' eneral %olerancin and .elated Princi/les

3' "molo

4' 8at!m .eferencin

' %olerances of Location

6' %olerances of orm& Pro5le& rientation& and.!no!t



12

Distor of the "tandard

$<"I 14'* 1964$<"I 14'*-1973

$<"I 14'*-19,2

$"* 14'*-1994 8imensionin and %olerancin

$"* 14''1*-1994 *athematical 8e5nitions

Stanle5 Par1er has #een credited %ith #ringing

to light the pro#lems that existed %ith limit

dimensioning %hile %or1ing at the 6o5al

Torpedo Factor5 in Scotland7



13

Identif the "tandard Bsed

$"* 14'*-1994 re!ires thestandard e identi5ed on the drain

hen it is a//lied'

*ethods chane as standards e:ol:e'For example8

A!SI 9*:7;,*34< ASME 9*:7;,*33:

A, A ,



14

eneral Information

International "stem of Bnits ("I) ha:e een!sed' B'"' C!stomar Bnits co!ld ha:e een !sed'

i!res are intended as ill!strations to aidin !nderstandin' %he sho one /ossilesol!tion'

Ca/ital letters on 5!res are intended toa//ear on 5nished drains'



1

o!ndations of *echanical$cc!rac

The Four echanical Arts

eometr

"tandards of Lenth

8i:idin the Circle

.o!ndness a5ne 67 Moore



16

8e:elo/ment of latness

"te/ 1 $lternate eteen /lates 1 and 2 !ntila relati:e match is achie:ed' Plate 1 arees ith /late 2

<one are +non to e Eat

"te/ 2 Consider /late 1 as the master /lateand or+ /late 3 to /late 1' Plate 1 arees ith /late 2

Plate 1 arees ith /late 3

<one are +non to e Eat

0ased on the %or1 o Sir =oseph hit%orth



17


"te/ 3 $lternate eteen /lates 2 and 3 !ntila relati:e match is achie:ed' Plate 2 arees ith /late 3

Plates 2 and 3 are +non to e Eatter that /late 1 <one are +non to e Eat

"te/ 4 Consider /late 2 as the master /lateand or+ /late 1 to /late 2'

Plate 1 arees ith /late 2 Plate 3 arees ith /late 2 <one are +non to e Eat $ll are of nearl e!al Eatness



1,


"te/ $lternate eteen /lates 1 and 3 !ntil arelati:e match is achie:ed' Plate 1 arees ith /late 3 Plates 1 and 3 are +non to e Eatter that /late 2 <one are +non to e Eat

"te/ 6 Consider /late 3 as the master /late and or+/late 2 to /late 3' Plate 1 arees ith /late 3 Plate 2 arees ith /late 3 <one are +non to e Eat $ll are of nearl e!al Eatness

Contin!e red!cin the error !ntil all three /lates aree'



19

3 8oc!ments for Prod!ct

#!alit

Prod!ct 8rain

Process 8e5nition

#!alit Control Plan



20

"ection 2

De!nitions, "ules, and #ym$ols



21

Fe 8e5nitions

Datum %heoreticall eGact /oint& aGis& or /lane deri:ed fromthe tr!e eometric co!nter/art'

Datum Feature $ct!al feat!re on a real /art !sed to

estalish a dat!m'

Datum Feature #imulator $ s!rface of s!Hcient /recisionto estalish a sim!lated dat!m'

#imulated Datum $ /oint& aGis& or /lane estalished /rocessin or ins/ection e!i/ment'

Datum Target $ s/eci5ed /oint& line& or area on a /art !sedto estalish the dat!m scheme'



22

Fe 8e5nitions

Feature of #i%e $ clindrical or s/herical s!rface& orto o//osin elements or /arallel s!rfaces'

east aterial 'ondition %his occ!rs here a

feat!re of sie contains the least material alloed the stated limits of sie'

a(imum aterial 'ondition %his occ!rs here afeat!re of sie contains the most material alloed the stated limits of sie'

"egardless of Feature #i%e $ term that indicatesthat a eometric tolerance or dat!m reference a//liesfor an increment of sie ithin its sie tolerance'



23

Fe 8e5nitions

Tolerance %he total /ermissile :ariation in sie for a s/eci5eddimension'

Bilateral Tolerance $ tolerance one here the o!ndar

conditions contain the s/eci5ed dimension'

Geometric Tolerance $ eneral term that refers an of the 14smols !sed to control form& orientation& /ro5le& r!no!t& orlocation'

)nilateral Tolerance $ tolerance one that onl eGists on oneside of the s/eci5ed dimension'

True Geometric 'ounterpart %he theoreticall /erfecto!ndar or est 5t (tanent) /lane of a s/eci5ed dat!mfeat!re'



24

!ndamental .!les

ach dimension shall ha:e a tolerance'

(eGce/t for those dimensions s/eci5call identi5ed as reference&maGim!m& minim!m& or stoc+)

ns!re f!ll !nderstandin of each feat!re'

"ho the detail needed and no more'

"er:e f!nction needs& no misinter/retation'

*an!fact!rin methods are not s/eci5ed'

<on-mandator dimensions are F'

8esined of o/timal readailit'



2

!ndamental .!les

8imension materials made to ae n!mers'

90o a//l hen feat!res are shon as '

90o a//l hen centerlines are shon '

8imensions a//l at 20oC (6,o)'

8imensions a//l in a free state'

%olerances a//l for f!ll sie of feat!re'

8imensions and tolerances onl a//l at the drain le:el here the eres/eci5ed'



26

Limits of "ie

Actual #i%e is a eneral term for the sie of afeat!re as /rod!ced' It has to inter/retations'

Actual ocal #i%e is the :al!e of the indi:id!aldistance at an cross section of an feat!re of sie'

Actual ating #i%e is the dimensional :al!e ofthe act!al matin en:elo/e'

imits of #i%e are the s/eci5ed minim!m andmaGim!m :al!es for a feat!re of sie'



27

.!le 1 %he %alor

Princi/le=;here onl a tolerance of sie is s/eci5ed&

the limits of sie of an indi:id!al feat!re/rescrie the eGtent to hich :ariations in its

eometric form& as ell as sie& are alloed'?$"* 14'*-1994

"im/l /!t@

Limits of sie for an indi:id!al feat!re controlthe alloale :ariation to its form and its sie'



2,

"ie Controls orm

%his on a drain

$llos this r this

According to "ule *+, a truegeometric counterpart at 'must pass through the hole



29

"ie Controls orm

%his on a drain

$llos this r this

According to "ule *+, a truegeometric counterpart at 'must pass over the pin



30

eat!res ith and itho!t"ie

8e5nition@ $ feat!re is a /hsical/ortion of a /art s!ch as a s!rface& hole&ta& slot& /in& etc'

eat!res ;itho!t "ie@ $n Plane "!rface

eat!res ;ith "ie@ Clindrical "!rface "/herical "!rface $ "et of 2 //osin lements or Parallel Planes



31

eat!res ;ith K ;itho!t "ie



32

**C K L*C ;or+sho/

7';<

7';(7>';?7((*

,7(((

<7':<

<7':4

7>';

?7(((<

,7(((<

Determine MMC and @MC or each eat"re o sie #elo%7



33

.!le 2

." a//lies to eometric

tolerances de5nin indi:id!altolerance& dat!m reference& oroth& here no modifin smol

has een s/eci5ed' **C and L*Cm!st e s/eci5ed here re!ired'



34

$n!lar Bnits

$n!lar8imensionin

ither derees& min!tes&and seconds or decimalderees ma e !sed'

Precede small anlesith eros for dereesand min!tes as /laceholders'

2o 30 4?

or2'12o

0o

0



3

*illimeter 8imensionin

Bse a sinle 0 to descrie!nilateral tolerances here theintended :al!e is nil'

or ilateral tolerances& !se thesame n!mer of sini5cant diitsin oth limits of sie'

or limit dimensionin& !se thesame n!mer of sini5cant diitsoth limits of sie'

or asic dimensions& tolerancecontrol is accom/lished thefeat!re control frame' ollor!les for millimeter dimensions'

2M 0-0'2

2M 0'10 -0'2

2'1024'7

2



36

8ecimal Inch

8imensioninor !nilateral tolerances& !sethe same n!mer of eros henthe intended :al!e is nil'

or ilateral tolerances& !sethe same n!mer of sini5cantdiits in dimension and limits'

or limit dimensionin& !se thesame n!mer of sini5cantdiits oth limits of sie'

or asic dimensions& !se thesame n!mer of sini5cantdiits as in the feat!re controlframe'

1'000M '000- '010

1'000M '004- '010

1'004'990

1'000



37

Location of eat!res

.ectan!lar Coordinate 8imensionin

.ectan!lar Coordinates No 8imension Lines

%a!lar 8imensionin

Polar Coordinate 8imensionin

.e/etiti:e eat!res or 8imensions

Bse of =O? to indicate =?



3,

%olerancin and .elatedPrinci/les

eneral Practices

8irect %olerancin *ethods

%olerance G/ressionInter/retation of Limits

"inle Limits

%olerance $cc!m!lation Chain 8imensionin ase Line 8imensionin 8irect 8imensionin



39

Chain 8imensionin;hat are the min andmaG :al!es eteens!rfaces O and Q



40

ase Line 8imensionin

;hat are the min andmaG :al!es eteens!rfaces O and Q



41

8irect 8imensionin

;hat are the min and maG :al!eseteen s!rfaces O and Q



42

Bse of asic 8imensions

asic dimensions de5ne the /erfectlocation of feat!res ith res/ect to thedat!m reference frame'

asic dimensions de5ne the theoreticaleGact sie and location for feat!res'

eat!re control frames de5ne theintended tolerance for feat!res'



43

Bnderstand Perfect eometr

Perha/s the est a to com/rehend8K% is 5rst to en:ision the eometrof the /erfect /art de5ned asicdimensions'

%hen e can a//l the tolerances i:en

in the feat!re control frames to de5nethe alloale :ariation from the /erfect/art'



44

Bsin %ales to8e5ne asic 8imensions

Parara/h 1'9 disc!sses locations of feat!res'

Parara/h 1'9'3 allos the !se of tales thatlist the location of feat!res as rectan!larcoordinates from m!t!all /er/endic!lar/lanes'

%ales ma e /re/ared in an s!italemanner that ade!atel locates feat!res'



4

eat!re Control rame"mols

Description #ym$ol

eat!re Control rame

8iameter

"/herical 8iameter

*aGim!m *aterial Condition

Least *aterial Condition

ProAected %olerance Rone

ree "tate

%anent Plane

"tatistical %olerance

7(*( A 0 C

S

M

@

P

F

T

ST



46

eat!re Control rame

lements Lael the elements of the feat!re control frame !sin the folloin ter

8at!m *odi5er eometric Characteristic8iameter "mol Primar 8at!meat!re *odi5er "econdar 8at!meat!re %olerance %ertiar 8at!m





4,

eat!re Control rames

Gam/le



49

eat!re Control ramePlacement

Locate the eat!re Control rame elo or attachedto the leader-directed dimension or callo!t'

.!n the leader from the frame to the feat!re'

$ttach a side or an end of the frame to an eGtensionline from the feat!re'

$ttach a side or an end of the frame to an eGtensionof the dimension line related to the feat!re in!estion'



0

ther Common "molsDescription #ym$ol

.adi!s .

"/herical .adi!s ".

Controlled .adi!s C.

.eference ( )

eteen

$ll $ro!nd

<!mer of Places ,OCo!nter ore or "/ot ace

Co!ntersin+

8e/th or 8ee/



1

eat!re Control rames

Gam/le



2

eometric Characteristic"mols



3

"ome ther eneral .!les

#tatistical Tolerancing $ssinment of com/onenttolerances to meet asseml needs of statistical stac+s'

"adius and Diameter 'allouts .& C.& ".& & and " '

-on."igid /arts *ethod of restraint m!st e s/eci5ed'

#cre0 Threads, Gears and #plines "cre threads

are e:al!ated at their /itch diameter !nless otherises/eci5ed' ears and s/lines m!st e s/eci5ed'



4

"ection 3

Applications of Tolerance 1ones



orm %olerances

latness

"traihtness

Circ!larit

Clindricit



6

orm %olerances

8at!m references are ne:er made forform tolerances'

.!le 1 sas that limits of sie control

:ariation in form'enerall& form tolerances are onlnecessar to re5ne (re!ire a tihtertolerance) limits of sie'

orm tolerances are often a//lied tofeat!res to !alif them as acce/taledat!m feat!res'



7

latness

De!nition latness eGists hen as!rface has all of its elements in one/lane'

Tolerance 1one %o /arallel /lanesithin hich the s!rface m!st lie'



,

Chec+in for latness



9

Pro/er $//lication of latness

<o dat!m is referenced'

It is a//lied to a sinle /lanar feat!re'

<o modi5ers are s/eci5ed'

%olerance :al!e is a re5nement of othereometric tolerances or .!le 1'



60

"traihtness

De!nition "traihtness eGists hen anelement of a s!rface or an aGis is astraiht line'

Tolerance 1one %o /arallel lines in thesame /lane for to-dimensional

a//lications' $ clindrical toleranceone that contains an aGis for three-dimensional a//lications'



61

Chec+in for "traihtness

P $ li ti f



62

Pro/er $//lication of"traihtness

a//lied to a "!rface lement<o dat!m is referenced'

It is a//lied to a s!rface element'

It is a//lied in a :ie here the element to econtrolled is shon as a line'


%olerance :al!e is a re5nement of othereometric tolerances or .!le 1'

"t i ht f t f



63

"traihtness of a eat!re of"ie

;hen straihtness is a//lied to afeat!re of sie@

%olerance one a//lies to the aGis orcenter/lane'

.!le 1 does not a//l'

%he tolerance :al!e ma e larerthat the limits of sie for the feat!reof sie'

P $ li ti f



64

Pro/er $//lication of"traihtness a//lied to a

eat!re of "ie<o dat!m is referenced'

It is a//lied to a /lanar or clindrical feat!re of sie'

If a /lanar feat!re of sie& the diameter smol is not !sed'

If a clindrical feat!re of sie& the diameter smol is !sed'

& % & and L modi5ers are not s/eci5ed'

%olerance :al!e is a re5nement of other eometrictolerances'

P

Ci l it



6

Circ!larit(ro!ndness)

De!nition Circ!larit eGists hen all of the/oints on a /er/endic!lar cross section of aclinder or a cone are e!idistant to its aGis'

Tolerance 1one %o concentric circles thatcontain each circ!lar element of the s!rface'

<ote@ Circ!larit also a//lies to s/heres'



66

Chec+in for Circ!larit

P $ li ti f



67

Pro/er $//lication ofCirc!larit


It is a//lied to a circ!lar feat!re'


%olerance :al!e is a re5nement of limitsof sie on the diameter or of others/eci5ed eometric tolerances'



6,

Clindricit

De!nition Clindricit eGists hen all ofthe /oints on the s!rface of a clinderare e!idistant to a common aGis'

Tolerance 1one %o concentric clindersthat contain the entire clindrical

s!rface'



69

Chec+in for Clindricit

Pro/er $//lication of



70

Pro/er $//lication ofClindricit


It is a//lied to a clindrical feat!re'


%olerance :al!e is a re5nement of limitsof sie on the diameter or of others/eci5ed eometric tolerances'

8 i i f



71

8ecisions for orm %olerances

Form

Tolerances

Consider

@imits o Sie

Flatness Straightness Circ"larit5 C5lindricit5

S"race

Elements

Axis or

Center Plane

Consider

Material Condition

MMC6FS



72


$n!larit

Per/endic!larit

Parallelism



73


8at!m references are alas !sed for orientationtolerances'

rientation tolerances a//lied to a s!rface controlthe form of toleranced s!rface'

nl a tanent /lane ma need control'

rientation tolerances ma e a//lied to controloth feat!res of sie and feat!res itho!t sie'

rientation tolerances do not control sie or

location'enerall& /ro5le tolerances are !sed to locatefeat!res itho!t sie and /osition tolerances are!sed to locate feat!res of sie'



74

$n!larit

De!nition $n!larit eGists hen all of the/oints on a s!rface create a /lane or afeat!re aGis is at the s/eci5ed anle& hen

com/ared to a reference /lane or aGis'Tolerance 1one %o /arallel /lanes at the

tr!e anle to a reference /lane and containthe entire s!rface s!rface'

<ote@ $//lies to median /lanes and aGes too'Dat"m Plane

Dat"m Feat"re



7

Chec+in for $n!larit




76

Pro/er $//lication of$n!larit

8at!m reference is s/eci5ed'

"!rface a//lications ma !se tanent /lane modi5er'

eat!re of sie a//lications ma !se **C& L*C&diameter& of /roAected tolerance one modi5ers'

asic anle de5nes /erfect eometr eteen thedat!m reference and the toleranced feat!re'

"/eci5ed tolerance is a re5nement of other eometrictolerances that control an!larit of the tolerancedfeat!re'



77

Per/endic!larit

De!nition Per/endic!larit eGists hen allof the /oints on a s!rface& median /lane& oraGis are at a riht anle to a reference

/lane or aGis'Tolerance 1one %o /arallel /lanes that are

/er/endic!lar to a reference /lane andcontain the entire s!rface s!rface'


Dat"m Feat"re

Chec+in for



7,

Chec+in forPer/endic!larit




79

Pro/er $//lication ofPer/endic!larit





"/eci5ed tolerance is a re5nement of other eometrictolerances that control the /er/endic!larit of thetoleranced feat!re'



,0

Parallelism

De!nition Parallelism eGists hen all of the/oints on a s!rface& median /lane& or aGisare e!idistant to a reference /lane or aGis'

Tolerance 1one %o /arallel /lanes that are/arallel to a reference /lane and contain theentire s!rface s!rface'


Dat"m Feat"re



,1

Chec+in for Parallelism




,2

Pro/er $//lication ofParallelism





"/eci5ed tolerance is a re5nement of other eometrictolerances that control /arallelism of the tolerancedfeat!re'

8ecisions for rientation



,3

8ecisions for rientation %olerances

Orientation

Tolerances

Parallelism Ang"larit5 Perpendic"larit5

Consider

@imits o Sie

Consider @imits

O @ocationFeat"re

o Sie

Plane

S"race

Consider

Material Condition

MMC6FS @MC



,4

Location %olerances

%r!e Position

"mmetr

Concentricit



,

Location %olerances

8at!m references are alas !sed for locationtolerances'

Location tolerances are reser:ed for tolerancina//lications on feat!res of sie'

%he are alas located asic dimensions ac+to the dat!m scheme'

Location tolerances shon on the same centerlineare ass!med to ha:e a asic dimension of ero'

"mmetr and concentricit a//lication arecentered ao!t the dat!m scheme s/eci5ed forthe controlled feat!re'



,6

%r!e Position

De!nition %r!e /osition is the eGactintended location of a feat!re relati:e to as/eci5ed dat!m scheme'

Tolerance 1one *ost fre!entl& thetolerance one is a clinder of s/eci5eddiameter ithin hich the tr!e aGis of thefeat!re m!st lie'

<ote@ %r!e /osition can also e a//lied tomedian /lanes relati:e to s/eci5ed dat!ms'



,7

Positional %olerancin

%raditional tolerancin (sa M '00?)consist of 2-8 rectan!lar o!ndaries'

$ circ!lar o!ndar ith the sameorst-case conditions increases thearea of the tolerance one 7S& /rior

to an on!s tolerance'

%raditional astener



,,

%raditional astener %olerances

%hreaded astener 3N, 16

Clearance Dole 13N32

Perect Condition

*B-: 7(*;-

orst,Case Condition

7((*;

Clearance



,9

on!s %olerances

;hen tolerancin feat!res of sie&on!s tolerances ma e a//licale'

;ith **C& as the sie of a holeincreases& so does the acce/taletolerance one& /ro:ided the hole doesnot eGceed its limits of sie'ole at

MMC

Original

Tolerance

one

@arger

ole

@arger

Tolerance

one

@arger

ole




90

*aGim!m *aterial Condition(**C)

Larest /ermissile eGternal feat!re' !tside 8iameter

Gternal eat!re "ie

Fe

"mallest /ermissile internal feat!re'

Doles "lots

Fe ;a



91


<ote@ 8at!m feat!re $ is the ac+ s!rface'




92

Least *aterial Condition(L*C)

"mallest /ermissile eGternal feat!re' !tside 8iameter

Gternal eat!re "ie

Fe

Larest /ermissile internal feat!re'

Doles "lots

Fe ;a



93



.eardless of eat!re "ie



94

.eardless of eat!re "ie(.")

." is no loner doc!mented eGce/t inrare cases here it is re!ired forclarit'

." is ass!med for feat!res of sie

hen neither **C nor L*C ares/eci5ed'



9

.eardless of eat!re "ie


$//lications of



96

$//lications of*aterial Condition *odi5ers

*aGim!m *aterial Condition Bsed for clearance a//lication'

Least *aterial Condition Bsed for location a//lications' Bsed to /rotect all thic+ness'

.eardless of eat!re "ie Bsed hen sie and location do not interact'

M

@

$//lications for



97

$//lications forLeast *aterial Condition

7;(>7;(* 7((< @

7;((

7:33

The p"rpose o the hole is to

locate the P@P pin #elo%7

orst Case Scenario

ole diameter at 7;(> @MCPin diameter at 7:33 @MC

Clearance is 7((:

Pin can shit 7((< in an5 direction

Tolerance or hole location is H 7((< at @MC

ole can #e o location 7((* in an5 direction

Pin can #e o location 7((> in an5 direction

$//lications for



9,


7;(>7;(* 7((< @

7;((

7:33



ole at MMC ) Pin at @MC

ole diameter at 7;(* MMCPin diameter at 7:33 @MC

Clearance is 7((<

Pin can shit 7((* in an5 direction

Tolerance or hole location is H 7((: at MMC

ole can #e o location 7((< in an5 direction

Pin can #e o location 7((> in an5 direction

$//lications for



99


7;(>7;(* 7((< @

7;((

7:33



ole at MMC ) Pin at MMC

ole diameter at 7;(* MMCPin diameter at 7;(( MMC

Clearance is 7((*

Pin can shit 7(((; in an5 direction

Tolerance or hole location is H 7((: at MMC

ole can #e o location 7((< in an5 direction

Pin can #e o location 7((<; in an5 direction

Tirt!al and .es!ltant



100

Tirt!al and .es!ltantConditions

2irtual 'ondition is the constant o!ndar enerated the collecti:e e>ects of a feat!res s/eci5ed **C orL*C and the eometric tolerance for that materialcondition (i'e& the /remise for f!nctional ain)'

"esultant 'ondition is the :ariale o!ndarenerated the collecti:e e>ects of a feat!ress/eci5ed **C or L*C& its eometric tolerance for thatmaterial condition& the sie tolerance& and an

additional eometric tolerance deri:ed from thefeat!res de/art!re from its s/eci5ed material condition(e''& eGtreme o!ndar alloed for a i:en sit!ation)'




101

Tirt!al and .es!ltantConditions

i:en **C

irt"al

Condition

Constant

al"e

aria#le

al"e

6es"ltant

Condition

Inner

0o"ndar5

O"ter

0o"ndar5

Internal Feat"re o SieH

<;7;<;7*

H (7* M

Ø Hole Ø Tol V Cond R Cond

<;7*

<;7<

<;7>

<;7:

<;7;

(7*

(7<

(7>

(7:

(7;

<;7<

<;7:

<;7-

<;74

<-7(

<;7(

Inner and !ter



102

e a d ! eo!ndar Conditions

H<;7;

<;7*

H (7* M

%olerance Rone$t **C

Tirt!al Condition

"ie

on!s %olerance$t L*C

Dole at L*C!tero!ndar

Innero!ndar




103

Conditions

i:en **C

irt"al

Condition

Constant

al"e

aria#le

al"e

6es"ltant

Condition

O"ter

0o"ndar5

Inner

0o"ndar5

External Feat"re o SieH

<:73<:7;

H (7* M

Ø Pin Ø Tol V Cond R Cond

<:73

<:74

<:7'

<:7-

<:7;

(7*

(7<

(7>

(7:

(7;

<:74

<:7-

<:7:

<:7<

<:7(

<;7(




104

Conditions

i:en L*C

irt"al

Condition

Constant

al"e

aria#le

al"e

6es"ltant

Condition

O"ter

0o"ndar5

Inner

0o"ndar5


<;7;<;7*

H (7* @

Ø Hole Ø Tol V Cond R Cond

<;7*

<;7<

<;7>

<;7:

<;7;

(7;

(7:

(7>

(7<

(7*

<:7-

<:74

<;7(

<;7<

<;7:

<;7-




10

Conditions

i:en L*C

irt"al

Condition

Constant

al"e

aria#le

al"e

6es"ltant

Condition

Inner

0o"ndar5

O"ter

0o"ndar5


<:73<:7;

H (7* @

Ø Pin Ø Tol V Cond R Cond

<:73

<:74

<:7'

<:7-

<:7;

(7;

(7:

(7>

(7<

(7*

<;7:

<;7<

<;7(

<:74

<:7-

<:7:

Inner and !ter o!ndaries



106

i:en ."

aria#le

al"e

aria#le

al"e

Inner

0o"ndar5

O"ter

0o"ndar5


<;7;<;7*

H (7*

Ø Hole Ø Tol I. B. O. B.

<;7*

<;7<

<;7>

<;7:

<;7;

(7*

(7*

(7*

(7*

(7* <;7-

2'0

Inner and !ter o!ndaries



107

i:en **C

aria#le

al"e

aria#le

al"e

O"ter

0o"ndar5

Inner

0o"ndar5


<:73<:7;

H (7*

Ø Pin Ø Tol O. B. I. B.

<:73

<:74

<:7'

<:7-

<:7;

(7*

(7<

(7>

(7:

(7; <:7:

2'0



10,

Rero %olerance at **C

;here ero tolerance is s/eci5ed at **C&the tolerance is totall ased on the act!almatin sie of the feat!re s/eci5ed'

Location and orientation m!st e /erfecthen the feat!re is at **C'

$s the feat!re de/arts from **C thealloale tolerance is ased on the sie thefeat!re com/ared to its **C'

Loic for Rero %olerance at



109

**C

A

H *7((- ? 7((>

H 7((: M A

0H 7;*: ? 7((>

H 7((; M A 0 M

A

H 733: ? 7((>

H 7((< M A

0H 7;(( ? 7((*

H 7((; M A 0 M




110

**C

H 7;(-

irt"al

Condition

0o"ndar5

H 7333

irt"al

Condition

0o"ndar5

F"nctional

Extremes are

H 733* and H 7333




111

**C

H 733: ? 7((>

H 7((< M A

0

0ased on ass"mptions a#o"t process .ariation$ %e ma5 ha.e ar#itraril5di.ided the total tolerance o H 7((4 into H 7((- or sie and H 7((< or

orientation7 e co"ld ha.e di.ided the tolerance into H 7((: ? H7((:$

or H 7((< ? H 7((-$ or e.en H 7((4 ? H 7(((7




112

**C

H 733; ? 7((:

H 7((( M A

0

h5 not gi.e the entire tolerance to the man"act"ring process and letthe process di.ide it "p as neededJ This is %hat happens %hen %e

speci5 ero tolerance at MMC7

Teri5cation of Position at



113

**C

1' 8etermine tolerance at **C'

2' 8etermine act!al matin sie'

3' Calc!late /ositional tolerance alloed'

4' 8etermine /ositional error in location'

' Com/are /ositional error in location to

/ositional tolerance alloed'

6' 8ecide to acce/t or reAect'

"/eci5cation of Position at



114

**C




11

**C




116

L*C

1' 8etermine tolerance at L*C'

2' 8etermine act!al matin sie'

3' Calc!late /ositional tolerance alloed'

4' 8etermine /ositional error in location'

' Com/are /ositional error in location to

/ositional tolerance alloed'

6' 8ecide to acce/t or reAect'

"/eci5cation of Position at



117

L*C




11,

L*C

P $ li ti f P iti



119

Pro/er $//lication of Position

Position control is a//lied to a feat!re of sie'

8at!m references are s/eci5ed and loical forthe a//lication'

asic dimensions estalish the desired tr!e/osition of the feat!re of sie'

%anent /lane modi5er is not !sed'

8iameter smol is !sed to s/ecif aGis control'

8iameter smol is not !sed to s/ecif center

/lane control'**C& L*C& or ." ma e s/eci5ed'

" t



120

"mmetr

De!nition "mmetr de5nes the locationof non-clindrical feat!res ao!t aderi:ed median /lane'

Tolerance 1one %he tolerance one isde5ned to /lanes& e!idistant to adat!m center /lane' %he deri:ed

median /oints m!st fall ithin these to/lanes'

A

"et B/ for "mmetr



121

"et B/ for "mmetr




122

"mmetr

$ /lanar feat!re of sie to e controlled!ses the same center /lane as the dat!mscheme'

8iameter smol is ne:er !sed to s/ecifthe smmetr tolerance'

**C& L*C& tanent /lane& and /roAectedtolerance one modi5ers ma not es/eci5ed'

C t i it



123

Concentricit

De!nition Concentricit de5nes thelocation of clindrical feat!res ao!t anaGis of rotation'

Tolerance 1one %he tolerance one isde5ned as a clinder ao!t the dat!maGis that m!st contain the median

/oints of diametricall o//osedelements of a feat!re'

A

Chec+in for Concentricit



124

Chec+in for Concentricit




12

Concentricit

%he s!rface of re:ol!tion to e controlledis coaGial to the aGis of the dat!m scheme'

8iameter smol is !sed to s/ecif theconcentricit tolerance'

**C& L*C& tanent /lane& and /roAected

tolerance one modi5ers ma not es/eci5ed'

8ecision *atriG for CoaGial



126

eat!res

/osition

3"F#4

Total "unout 'oncentricity

'ost

to/roduce

5 555 55

'ost

to

Inspect

5 55 555

'haracteristics

under

'ontrol

ocation

and6rientation

ocation

6rientationand Form

ocation

and6rientation

8ecisions for Location



127

%olerances@ocation

Tolerances

PositionConcentricit5 S5mmetr5

Center

Plane Axis

Determine

Tolerance

For Position Onl5

Consider Material Condition

MMC6FS @MC

Pro5le %olerances



12,

Pro5le %olerances

Pro5le of a Line

Pro5le of a "!rface

<,D Application

>,D Application

Pro5le %olerances



129

Pro5le %olerances

Pro5le tolerances are !sed to control m!lti/leco/lanar s!rfaces'

Perfect eometr m!st e de5ned :ia asicdimensions'

%he defa!lt inter/retation for the tolerance oneis ilateral and e!al ao!t the tr!e /erfecteometr'

Pro5le tolerances are not !sed to control feat!resof sie so **C& L*C& and ." do not a//l'

Pro5le feat!res can e !sed as dat!m feat!res orthe m!st e related to a de5ned dat!m scheme'

Pro5le



130

Pro5le

De!nition Pro5le de5nes thetheoreticall eGact /osition of a s!rface(3-8) or the cross section of a s!rface (2-

8)'

Tolerance 1one $ !niform o!ndar on

either side of the tr!e /ro5le that m!stcontain either the s!rface or line'

>,D Application <,D Application

Pro5le for Cam $//lication



131

Pro5le for Cam $//lication

!nctional ain of



132

Pro5le

Pro/er $//licationf P 5l % l



133

of Pro5le %olerances

Pro5le feat!res are !sed as dat!m feat!resor related to a de5ned dat!m scheme'

and

asic dimensions relate the tr!e /ro5leac+ to the dat!m scheme'

or

%he /ro5le tolerance :al!e m!st e a

re5nement of dimensions !sed to locatethe tr!e /ro5le'

8ecisions for Pro5le% l



134

%olerancesProile

Tolerances

Consider

@imits o Sie

Proile o a

S"race

Proile o a

@ine

Consider

Tolerance one

0ilateral+nilateral

Inside O"tside EK"al +neK"al

.!no!t %olerances



13

.!no!t %olerances

Circ!lar .!no!t

%otal .!no!t

<,D Application

>,D Application



Chec+in for .!no!t



137

Chec+in for .!no!t

Pro/er $//lication of .!no!t



13,

Pro/er $//lication of .!no!t

%he s!rface to e controlled is eithercoaGial or /er/endic!lar to the aGis ofthe dat!m scheme'

8iameter smol is ne:er !sed tos/ecif a r!no!t tolerance'

**C& L*C& tanent /lane& and /roAectedtolerance one modi5ers ma not es/eci5ed for a r!no!t tolerance'

8ecisions for .!no!t% l



139

%olerances

6"no"t

Tolerances

Consider

@imits o Sie

Total

6"no"t

Circ"lar

6"no"t

eometric Characteristicsf . d t



140

for .o!nd eat!res

Circ!larit (ro!ndness) :al!ates cross section of s!rface to its on aGis

Clindricit

:al!ates entire s!rface to its on aGis.!no!t :al!ates cross section of s!rface to a de5ned aGis

%otal .!no!t

:al!ates entire s!rface to a de5ned aGisConcentricit :al!ates est 5t aGis of feat!re to a de5ned aGis

%olerance 8esin loCh t



141

ChartDesign

6eK"irements

Esta#lish

Dat"ms

Indi.id"al

Feat"res 6elated

Feat"res

Indi.id"al or

6elated Feat"res

Form

Tolerances Proile

Tolerances

@ocation

Tolerances

6"no"t

Tolerances

Orientation

Tolerances

"ection 4



142

"ection 4

Datums and Datum #chemes

.eference Planes(The Point of Known Return)



143

(The Point of Known Return) %ed !sch& 1962

8e5ne the dat!m reference frame'

Bse of m!t!all /er/endic!lar /lanes'

%he oal is the re/lication of meas!rements'

Immoilie the /art in !/ to siG derees offreedom'

%heoreticall Perfect t



144

eometr

%hree m!t!all /er/endic!lar /lanes'

Dat"m

Point

> Dat"m Planesdeine the Origin

o Meas"rement

Criteria for "electin 8at!meat!res



14

eat!res

eometric .elationshi/ to %oleranced eat!re

eometric .elationshi/ to 8esin .e!irements

$ccessiilit of the eat!re

"!Hcient in "ie to e Bsef!l

.eadil 8iscernale on the Part

8esinatin Precedence of8at!ms



146

8at!ms

$l/haetical order is not rele:ant'

rder of /recedence is shon in the

feat!re control frame'

Consider f!nction 5rst'

%hen& consider the /rocess neGt' inall& consider meas!rement /rocesses'

8at!m eat!res of "ie



147

8at!m eat!res of "ie

**C callo!ts on a dat!m feat!res of siecan allo a dat!m shift on the eGactlocation of the dat!m feat!re'

%his a//lies to@ Clindrical "!rfaces (internal or eGternal) "/herical "!rfaces $ "et of 2 //osin lements or Parallel Planes $ Pattern of eat!res s!ch as a olt Dole

Pattern

8ecisions for 8at!m" l ti



14,

"electionSelect

Dat"m Feat"re

Feat"re

o SieS"race

AxisCenter

Plane

Consider

Material Condition

MMC6FS @MC

Are Other Dat"ms 6eK"iredJ

.ational "tratefor 8at!m "election



149

for 8at!m "election

It is reasonale to /rioritie the dat!mselection /rocess as follos@

1' !nctional .e!irements

1' Prod!ction .e!irements

1' *eas!rement .e!irements

;hat $re ;e .eall InterestedInQ



10

InQ

1' rror in eometric orms

2' "ie for eat!res of "ie

3' Location of eat!res

Introd!ction to 8at!m;or+sho/



11

;or+sho/

"elect dat!ms ased on f!nction'

"ome feat!res are leaders& others are folloers'

"e!ence of considerations@ stalish the dat!m reference frame (8.)'

#!alif the dat!m feat!res to the 8.'

.elate remainin feat!res to the 8.'

or consistenc& ass!me '00? tolerance ones!nless otherise s/eci5ed'

"elect and !alif the dat!m feat!res and identifthe dat!m /oint as s/eci5ed in the folloineGam/les'

8at!m ;or+sho/

Locate the /art on the ac+s!rface 5rst& then the ottomede& then the left side'



12

8at!m ;or+sho/

8at!m ;or+sho/

Locate the /art on the ac+s!rface 5rst& then the ottomede& then the riht hand sideof the ottom slot



13

a ! o s o/of the ottom slot'

8at!m ;or+sho/

Locate the /art on the ac+s!rface 5rst& then the ottomede& then centrall to theottom slot ith a 99, :irt!al



14

/ottom slot ith a '99, :irt!alsie +e'

8at!m ;or+sho/

Locate the /art on the fronts!rface 5rst& then a 1'04:irt!al sie hole for the lareoss then a 996 :irt!al



1

/oss& then a '996 :irt!alsie +e for the riht hand slot'

8at!m ;or+sho/

Locate the /art on the fronts!rface 5rst& then a 1'02:irt!al sie hole for the lareoss then the ottom ede



16

/oss& then the ottom ede' %he ottom ede m!st lie in a

tolerance one from 2'490 to2'10 from the lare oss'

"ection



17

Tolerancing #trategies

Process for %olerance$nalsis



1,

$nalsisEsta#lish Perormance 6eK"irements

De.elop a @oop Diagram

Con.ert Dimensional 6eK"irements toTarget al"es %ith EK"al 0ilateral Tolerances

Calc"late ariation or Perormance 6eK"irement

Select the Method o Anal5sis

Determine the Target al"e or 6eK"irement

"tatement of the Prolem



19

$ /rolem ell de5ned is half sol:ed' John 8ee

%horo!h /rolem de5nition ma lead directl toits sol!tion'

Dans aAaria

%he form!lation of a /rolem is far more often

essential than its sol!tion& hich ma e merel

a matter of mathematical or eG/erimentals+ill'

$lert instein

$sseml "tac+-B/ $nalsis



160

/

;hat is the minim!m and maGim!ma/ eteen the ottom of the collarand the !//er earinQ

Com/onent %olerances



161

/

"tac+ $nalsis .es!lt



162

;hat is the minim!m and maGim!ma/ eteen the ottom of the collarand the !//er earinQ

;orst Case :al!ation



163

<ominal $sseml Lenth U 1'000 M '00 M 2'000 U 3'00

%olerance of $sseml Lenth U '002 M '001 M '004 U M '007

;hile this a//roach of addin com/onent tolerances is mathematicallcorrect& in /ractical a//lication it is often too conser:ati:e'

A 0 C

Assem#l5 @ength

*7(((

? 7((<

7;((

? 7((*

<7(((

? 7((:

;orst Case Pros and Cons



164

Pros <o ris+ of com/onents not interactin /ro/erl'

100S interchaneailit of com/onents'

Cons *ethod is conser:ati:e'

Bnder!tiliation of f!ll tolerance rane'

%olerances for interactin dimensions aresmaller than necessar& hich ma increasecost'

"tatistical *ethod ofLinear :al!ation



16

Linear :al!ation

<ominal $sseml Lenth U 1'000 M '00 M 2'000 U 3'00

%olerance of $sseml Lenth U '0022 M '0012 M '0042 U M '0046

%o statisticall calc!late the tolerance e ta+e the root of the s!mof the s!ared :al!es of the indi:id!al tolerances (."")'

A 0 C

Assem#l5 @ength

*7(((

? 7((<

7;((

? 7((*

<7(((

? 7((:

"ome Critical $ss!m/tions



166

Com/onent dimensions are inde/endent'

Com/onents are assemled randoml'

Com/onent sho!ld e normall distri!ted'

%he act!al a:erae :al!e for each com/onent ise!al to the nominal :al!e s/eci5ed for that

com/onent' (therise& the nominal :al!e for theasseml ill not e met and the tolerances illnot e realistic') Process control is needed'

rom Part %olerances to an$sseml %olerance



167

$sseml %olerance

A

0

C

Assem#l5

ariances are additi.e %hile

standard de.iations are not7

"tatistical %olerancinPros and Cons



16,

Pros and Cons

Pros Larer tolerances on interactin dimensions'

Cons

"mall /ercent of 5nal assemlies fall o!tsidelimits'

"/ecial Considerations $:eraes of interactin dimensions m!st e

controlled :ia :ariales meas!rements' Interactin dimensions m!st e inde/endent and

normall distri!ted' Lot sie sho!ld e moderatel lare'

rom an $sseml %oleranceac+ to Com/onent



169

ac+ to Com/onent

%olerances

In /ractice& e are often re!ired to ein ith a de5ned end res!ltand determine a//ro/riate tolerances for the com/onents'

A

0

C Assem#l5

%o %heorems of.ele:ance



170

.ele:ance

%o theorems hold reat im/ortance inthe interrelationshi/ of tolerances'

%he 5rst is similar to the Pthaorean

%heorem

%he second theorem a//ears lesso:io!s@

)...( 223

22

21sum n

σ σ σ σ σ ++++=

)( 22

2121

σ σ σ +=− A

0

Com/osite %olerances and"inle "ement %olerances



171

"inle "ement %olerances

%here are times henit is more im/ortantto control therelationshi/s eteenfeat!res than to

control their locationsto the dat!ms'

"tandard Positional %olerance



172

!nctional ae for Tirt!alCondition of Doles to 8at!ms



173

Com/osite %olerance ithne 8at!m in the Loer



174

"ement

Com/osite %oleranceeat!re Control rame



17

PL%R locates and orientsfeat!res to the s/eci5eddat!ms :ia asicdimensions'

.%R locates the feat!resithin the /attern :ia asicdimensions to each otherand controls theirorientation relati:e to thes/eci5ed dat!m(s)'

.%R releases the /atternfrom the re!irementsi:en asic dimensionsto their dat!m feat!res'

Pattern Locatin

%olerance Ronerameor+

(PL%R)ne %oleranceRone "mol

eat!re .elatin

%olerance Ronerameor+(.%R)

%o !nctional aesfor the Com/osite %olerance



176

/

Com/osite %olerance ith %o 8at!ms in the Loer



177

"ement

%o !nctional aesfor the Com/osite %olerance



17,

/

%o "inle "ements ith %o 8at!ms in the Loer



179

"ement

%o !nctional aes for the %o "inle "ement



1,0

%olerances

iGed and loatinastener Calc!lations



1,1

loatin astener scenario eGists hen thefastener m!st /ass thro!h to clearanceholes in matin /arts'

iGed astener scenario eGists hen one of the/arts has threaded holes and the other /arthas clearance holes'

ProAected %olerance Rone sho!ld e !sed tos/ecif the heiht o!t of the threaded holethat the tolerance one a//lies'

%hreaded Doles



1,2

=%hreaded holes arent reall holes'

%he are a :ehicle to locate and

orientate matin /arts'?Carl Lance

<!s on a shoer head eha:e thesame as a threaded hole'

%o Clearance Doles loatin orm!la $//lication



1,3

//

;hat sho!ld e !se as the/ositional tolerance for eachof these to matin /artsQ

**C of clearance holes min!s **C of fastener is i:en to the /ositionaltolerance of oth /ieces'

%o Pieces .e!ired

'404- '37

'029

$ss!min a 3N, 16threaded fastenerV

%hreaded Dole ith ClearanceDole '404



1,4

iGed astener $//lication;hat tolerances sho!ld e !se for /ositional

tolerances for these to matin /artsQ

**C of clearance hole min!s **C of fastener m!st e sharedeteen theto /ositional tolerance of the to /ieces'

-'37

'029

%o/ics ;orth of 8isc!ssion



1,

8e5nition of !nctional .e!irements

ail!re *ode and >ects $nalsis

Consistent %oolin and ain Locators

Comm!nication ith "!//liers

8e:elo/in /timal "/eci5cations

"o!rces of Tariation



1,6

%he folloin /rimar contri!tors to od-in-hite:ariailit ere identi5ed as /art of the $!to odConsorti!ms 2mm Proram for Tariation .ed!ction@

Locator Pins 2,'4S

Incomin *aterial 21'3S ;eldin 19'1S

Clam/in 13'S

.oot Prorammin '0S

Carriers 3'S

.o!h Locators 2',S

<C loc+s 2',S

"o!rces of Tariation



1,7

$ s!mmar of the so!rces of locator /in /rolems@ "ie 22'S Pin Interference ith Panel17'S Loose Pins 12'S

Pin %oo "hort 7'S PLP #!antit 7'S

Pin PLP "election 7'S Pins <eeded .otatin '0S ;orn Pins '0S

*issin Pins '0S Pin "ha/e 2'S Pin %oo Lon 2'S

ther "o!rces of Tariation



1,,

ra:it

Clam/ "e!ence

%ool Interference

%ool .e/eatailit

*eas!rement rror

Incomin Part #!alit

Bncoordinated 8at!m "chemeClearance from Clam/ iner to <et loc+

En.ironment

EK"ipment

Material

Methods

People

"ection 6



1,9

Functional Gaging

*erits of !nctionalain



190

"im/le !nctional Chec+s for Conformit

%a+es $d:antae of on!s %olerances

Chec+s Parts for their Tirt!al Condition

$llos for est-it "ol!tions

.eAects Less !nctionall ood Parts

!nctional ainPros and Cons



191

Pros .ed!ces ris+ of shi//in ad /rod!ct' .ed!ces ris+ of scra//in ood /rod!ct'

.ed!ces ins/ection costs' Pro:ides attri!te data'

Cons 8oesnt /ro:ide :ariales data' Bs!all ont !alif for PP$P s!mission' *a not correlate ith C** data'

!nctional ain ofPro5le



192

;hat to 8o $o!t 8esinrrorsV



193

%he 5rst thin o! ant to do ao!t desin error isto 5nd them earl'

$s h!man nat!re o!ld ha:e it& most desiners

seem to ant to foc!s on the neGt desin& ratherthan s/endin their time on /ast mista+es'

If o! can identif desin errors earl in the desin

re:ie /rocess& the /otential of act!all ettinthe drains corrected is often m!ch reater'

"ome thins to Loo+for in 8esin .e:ies



194

8at!m schemes that dont ma+e sense'

8at!m schemes that dont match the /hsics ofasseml'

8at!m schemes that are in conEict ith themsel:es'

8at!m schemes that ill e diHc!lt to man!fact!re'

8at!m schemes that ill e diHc!lt to ins/ect'




19

eometric tolerances that arent referenced to adat!m scheme hen the sho!ld e'

eometric tolerances that are referenced to a

dat!m scheme hen the sho!ldnt e'

8iameter smols !sed here the sho!ldnt e!sed'

8iameter smols not !sed here the sho!lde'




196

Bse of eometric tolerances that dont re5neeither the limits of sie or other tolerances'

Patterns of holes here the !antit of holes

has not een s/eci5ed'

8imensional re!irements that cant e made'

8imensional re!irements that cant echec+ed'

Process for 8esin Chane



#!alit manaement sstems re!ire ade5ned /rocess for desin chanes ithin thesco/e of desin control'

8esiners need eG/licit and acc!rate feedac+to im/ro:e oth c!rrent and f!t!re desins'

If drains arent !/dated to eliminate desin

Documents

GD&T PPT GENERAL