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3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 20121Hitchhiker’s Guide to GeometricDimensioning & TolerancingThomas AllsupCo-Chair of North Texas SolidWorks Users Group
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Presentation Available2Download Now We survived another SolidWorks World. Last session of the conference. They announced where 2014 would be at thismorning. If you are still here and have your brainengaged then this must be important to you. You can find this and other GD&T and technicalPowerPoint presentations on our website. Proceedings with audio will be available in afew weeks.
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Thomas Allsup3About the Presenter Sixth time SWWorld Attendee Third time presenter. Co-chair of North Texas SolidWorks UsersGroup BSME Oklahoma State University MSME University of Texas at Arlington Partner at Anida Technologies, L.P., a Dallasbased engineering consulting company. GD&T Aficionado
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Previously at SolidWorks World4Three makes a trilogy or is it five In 2009, “How to Spell GD&T” started our discussion of GeometricDimensioning and Tolerancing concentrating on the fourteen basicsymbols using the FOPRL chart. In 2010, “How to Spell GD&T Part II: Revenge of the Circled Letters”concentrated on the modifiers in GD&T symbols. Now in 2013, we are ready for the next exciting chapter in the GD&TSaga where we will answer the question “To GD&T, the Universe, andEverything.”
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Agenda5Don’t Sweat the Small Stuff, It’s All Small Stuff
63DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Updated FOPRLChartNow based on ASMEY14.5-2009
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012When Do I Add Geometric Dimensioning and Tolerancing7
83DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012How Do I Interpret Geometric Dimensioning andTolerancing.
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Tolerance Zones versus Shapes9My money is on Shapes kicking Zones’ hiney Total Wide Tolerance Zone Cylindrical Tolerance Zone
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Sign Language10
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Exceptions11Mostly Harmless
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Lesson in GD&T12Rule #1 of GD&T states that the geometric formof a feature can vary so long as it stays withinthe limits of its size tolerance.Another way of saying this rule is to say sizetolerance is the primary control of a feature andthat GD&T is a refinement within that tolerance.The first magnitude of control is size.
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012What’s Rule #1 Mean?13GD&T symbols refine the shape or geometric control thatstarts with simply checking the dimensions of the partto the drawing.The best example to illustrate this is not from the GD&Tstandard but from the surface finish callout.
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Surface Roughness14Surface FinishSurface finish is a measurement of the surfaceroughness.Surface roughness height is measured:microinches (millionths of an inch)micrometers (millionths of a meter)Roughness spacing is measured in inches or millimeters.
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Surface Roughness15SymbolAMaximum Roughness AverageBMinimum Roughness AverageCMachining AllowanceDLay SymbolERoughness Sampling LengthFMaximum Waviness Height RatingGMaximum Waviness Spacing Rating
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Surface Roughness16Removal of MaterialRemoveMaterialDo NotRemoveMaterialMethodNotSpecified
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Surface Roughness17Surface Lay Symbols Perpendicular to surface indicated (wink) you like this symbol Parallel to surface indicatedXAngular in both directionsM MultidirectionalCCircular with center on surface indicatedRRadial with center on surface indicatedPNondirectional, pitted, or protuberant
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Surface Roughness18You don’t start by inspecting the surface finish of a plate.Initially you would measure the length, width, and thickness andmake sure the dimensions are in tolerance.If the parts don’t match the tolerances then it doesn’t make sense towaste time checking how the surface is finished.The last inspection step would be to check the surface finish.Surface Roughness is a refinement of the limits of size.
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Rule #1 Revisited19If the first rule of GD&T states that the geometric form of a featurecan vary so long as the feature stays within the limits of its sizetolerance then we better understand limits of size.The limits of size are the minimum acceptable measure value andmaximum acceptable measured value for a dimension.Geometric tolerancing should only be added when form must bemore accurately controlled or to conveyfunctional/interchangeability requirements.
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Limits of Size 0450.750.475.525.951.05.08.182.500 has no tolerance20
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Opinion21What is the difference in connotation in a limits dimension and abilateral toleranced dimension?Isn’t .100-.150, the same as .125 .025?Answer #1: Limits of acceptable dimensions are identical for both.Answer #2: Manufacturing people don’t target .125 when they seelimits but rather the tool safe side and let wear bring them down tothe other extreme.Answer #3: What should the CAD model show for limit dimensions?The average is not really the target so why not show it at the eitherthe minimum or maximum values?
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012ASME Y14.5M-1994 CAD/CAM Data22Section 2.1:“If CAD/CAM database models are used andthey do not include tolerances, thentolerances must be expressed outside ofthe database to reflect designrequirements.”This section clearly states that models may includetolerances hence paving the way to eliminatingconventional drawings someday!
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012ASME Y14.5-2009 CAD/CAM Data23In Section 1.2.1 Cited Standards now has ASME Y14.412003 (reaffirmed in 2008) Digital Product DefinitionData Practices.Provides guidance to 3D model with embedded dimensions andtolerances.Numerous new citations back to this standard.This topic came up in Austin during one of my Primer lectures andI wanted to mention that the embedded 3D data has beenallowed since 1984 but now it is really well documented.
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Tolerance Zones and Shapes24The next stop on the GD&T primer train is the ToleranceZones and Shapes station.These sound like the same thing but they are twoseparate but related items for tolerances.Let’s start with the easy one - zones.
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Tolerance Zones25All controls can have TOTAL WIDE TOLERANCE ZONES.Except Concentricity.Only five can have a CYLINDRICAL TOLERANCE ZONES:Position tolerance zones for holesPositionand bosses are always cylindricalOrientationtolerance zones. Parallelism, Angularity, PerpendicularityStraightnessConcentricity requires CYLINDRICAL TOLERANCE ZONE.
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Tolerance Zone Symbology26f.014m UTotal wide zone is defaultUNLESS.You put the diameter symbol here.jn.002l Y
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Tolerance Zone Shapes27Cylindrical zone sounds easy - it’s a circle or cylinderwithin with which the feature must reside to beacceptable.What shape is a total wide zone?Here’s where it gets complicated and one of the reasonsI originally built the FOPRL chart - let’s look at theshapes.
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Tolerance Zone Shape:28Form Total WideEach geometric control has it’s own total wide toleranceshape that is suggested by it’s name.FormStraightness: between two linesFlatness: between two planesCircularity: between two circlesCylindricity: between two cylinders
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Tolerance Zone Shape:29Orientation Total WideFor all three orientation controls, the surfaces must liebetween two planes.ParallelAngularityPerpendicularHold it a second, we just said flatness control wasbetween two planes.
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Tolerance Zone Shape:Profile / Runout Total WideProfileLine: between two curves that are the shapeof the featureSurface: between two surfaces that are theshape of the featureRunoutFull indicator movement30
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Tolerance Zone Shape:31Location Controls Total WidePosition: depends on the geometry it controlsBetween resultant and virtual conditions and fixed /floating fastener theory, there’s a day’s worth oftopics on positional tolerances.Symmetry: two planesConcentricity: cylindrical
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Form32Straightness ExceptionRule 1 has four (count’em four) exceptions:Stock parts : Bars, sheets, tubing, structural shapesParts subject to free state variationAdd note to a surface or feature: PERFECT FORM AT MMC NOTREQUIRED.Straightness tolerance on features of size with MMC applied.Straightness is the important exception at the end.
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Straightness Tolerance33on Features of Size with MMC AppliedPretty much, just like it sounds.The shaft shown below can be shaped like a “smileyface” and still be acceptable.J
3DS.COM/SOLIDWORKS Dassault Systèmes Confidential Information 4/26/2014 ref.: 3DS Document 2012Wrap Up34So Long and Thanks for all the Fish
ASME Y14.5M-1994 CAD/CAM Data . S s 4 2 23 In Section 1.2.1 Cited Standards now has ASME Y14.41-2003 (reaffirmed in 2008) Digital Product Definition Data Practices. Provides guidance to 3D mode
