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1、GD&T for Body1GD&T for Body EngineeringCourse content课程内容Introduction to GD&TGD&T介绍5 Step Process5步方法2GD&T for Body EngineeringIntroduction介绍What is GD&T什么是GD&THow it affects Ford Motor Company它如何让影响福特汽车公司3GD&T for Body EngineeringWhat is GD&T什么是GD&TGeometric Dimensioning and Tolerancing is a techni
2、cal data base through which our Product Design and Manufacturing Organisations can talk to one another via Product Data, whether on paper or the computer graphics screen几何尺寸公差是贯穿我们产品设计和生产制造的技术数据基础，无论是通过图纸或者是计算机上的图表，我们都能通过产品数据与其他人沟通。It is the engineering product definition standard that geometrically
3、 describes design intent and provides the documentation base for the design of the quality and production system.工程产品定义标准，几何尺寸描述设计意图，并为品质设计和产品系统提供文件基准。It is a technique of communication between Product Engineering and Manufacturing Engineering that promotes a uniform interpretation of the requiremen
4、ts for making a component.它是一种在产品工程和制造工程之间的技术交流，并促成一种针对零部件制造要求的唯一的解释。4GD&T for Body EngineeringWhat is GD&T什么是GD&TGDT provides the dimensions of the component and the tolerances in a language that eliminates confusing and inconsistent notes, datum lines, and location point identifications, and repla
5、ces them with standard symbols that refer to a universal code. GDT提供部件的尺寸和公差，用一种语言，它能够消除混淆和不一致的注释，基准线，定位点辨认，并且用与一种通用的代码相关的标准符号替换他们。This code describes the dimensions and tolerances of the component with reference to the relationships of the features to each other and their functional interfaces with
6、 mating parts, assemblies, etc.代码描述了关于部件间相互关系的特征的尺寸和公差，和他们匹配的部件的功能界面，总成等。5GD&T for Body EngineeringAuthorisation批准In 1990 Ford World-wide adopted the American National Standard for Dimensioning and Tolerancing, currently the ASME Y14.5M 1994. The authorisation for the above is documented in Standard
7、 D-1 of the Ford Engineering CAD and Drafting Standards and is referenced on all our released data.在1990 福特全球范围内采用美国尺寸公差标准，目前的ASME Y14.5M 1994。This information can be accessed via Ford intranet;http:/ above document also contains an electronic copy of the ASME Y14.5M 1994 Dimensioning and Tolerancin
8、g Standard.6GD&T for Body EngineeringApplicationThe application of GDT is initially the responsibility of the relevant Component Engineer, however teamwork is the key to the correct application through the component Core Team.This provides the opportunity for all disciplines to contribute their part
9、 of the total design package. It ensures part data will satisfy design intent as well as manufacturing and inspection requirements based on function, machine capability and available technology. 7GD&T for Body EngineeringApplicationIt provides the opportunity for proper Datum selection and has the p
10、otential to significantly reduce product changes, especially those changes following final product release. The Core Team should consist at a minimum of representatives from Product Engineering, Design Engineering, Manufacturing Engineering, and Quality Engineering.8GD&T for Body EngineeringMore inf
11、ormationFord Engineering CAD and Drafting Standardshttp:/ Applicationhttp:/9GD&T for Body EngineeringHow GD&T Relates to FordThe correct application has the potential to;Influence Fit and FinishReduce ReworksIncrease ReliabilityAffects Assembly ProcessReduce cost10GD&T for Body EngineeringThe 5 Step
12、 Process1 2 3 4 511GD&T for Body Engineering5 Step Process1 Utilise the new Design Concept2 Establishment of the Datum Reference Frame3 Establish GD&T Controls4 Establish Tolerances5 Final Approval of GD&T on Cad Data12GD&T for Body EngineeringStep 1Utilise new design concept13GD&T for Body Engineer
13、ingUtilise new design conceptThe 1st step involves making decisions at the basic design stage that will ultimately effect the design, manufacture and verification of the final component.This can only be successfully achieved by the relevant PD representative attending the Master Control Plan (MCP) M
14、eetings. 14GD&T for Body EngineeringMaster Control PlanWhat is the purpose of the MCP meeting in relation to PDTo establish a common understanding for the verification process of the major panels, e.g. Bodyside, Hood, Deck Lid, Door, Roof, Underbody, etc.To obtain agreement at an early stage of the
15、design for the datum reference frame, die approach, etc.Who attends the MeetingPD and Manufacturing, i.e. Body Engineering, DCD, Stamping, Body and Assembly.15GD&T for Body EngineeringMaster Control PlanWhen should the Meeting take place. Initial design concept stage, knowing the components paramete
16、rs such as size and function Current methods use;Past evidence, past experience, can sometimes hinder rather than assist the new design conceptResult of meetingMay be documented in CAD, or paper form16GD&T for Body EngineeringStep 2Establish Datum Reference Frame17GD&T for Body EngineeringEstablish
17、Datum Reference FrameAs part of the Master Control Plan (MCP) Process meeting, Body Engineering and Manufacturing agreed to the definition of the Datum Features and their location.PD have Ownership of the Datum Features.18GD&T for Body EngineeringDatum Reference Frame (Reference Pocket Guide, Page 8
18、)Consists of a set of three mutually perpendicular planesThe reference frame exists in theory only and is not on the partSufficient datum features are used to position the part in relation to the Datum Reference Frame.19GD&T for Body EngineeringDatum FeaturesAn actual feature of the part used to sta
19、ge/position the part in the equipment for purposes of relating its geometry to the Datum Reference Frame.20GD&T for Body EngineeringPrimary Datum PlaneAchieved by establishing a minimum of three Points to define a plane 21GD&T for Body EngineeringPrimary Datum PlanePrimary Datum Plane should be Para
20、llel to Die Plane22GD&T for Body EngineeringPrimary Datum PlaneWhen Datum Target Areas defining Primary Datum Plane are not on one single planar surface, they must be controlled one to another using the PROFILE of a SURFACE geometric control.23GD&T for Body EngineeringSupporting a panel only on the
21、designated Datum Target Areas, effectively removes 3 degrees of freedom, i.e. 1 Linear and 2 Rotational.24GD&T for Body EngineeringDatum Target AreasDatum Target Areas should wherever possible be planar and parallel to the die plane.Primary Datum Plane25GD&T for Body EngineeringDatum Target AreasDed
22、icated Datum Target Areas makes both the part, and gauge/fixture more robust, cost effective and Improves repeatability26GD&T for Body EngineeringSecondary Datum FeatureGenerally a Datum Feature of Size is used , i.e. Single circular Hole, positioned on a surface that is parallel to the Primary datu
23、m Plane, and is ultimately used as a four way locator.27GD&T for Body EngineeringSecondary Datum FeatureControlled relative to the Primary Datum Plane using the Geometric control PERPENDICULARITY.28GD&T for Body EngineeringSecondary Datum FeatureThe intersection of the derived axis of the feature pe
24、rpendicular to the Primary Datum Plane, and the design side of the component is the local origin of all basic dimensions; 0,0,029GD&T for Body EngineeringSupporting a panel on the designated Datum Target Areas, and using the four way locator removes another 2 Linear degrees of freedom, resulting in
25、all 3 Linear, and 2 Rotational degrees of freedom constrained.30GD&T for Body EngineeringTertiary Datum FeatureGenerally the width of a Slotted Feature of Size is used as a two way locator.31GD&T for Body EngineeringTertiary Datum FeatureTo eliminate tolerance of Datum Shift on one of the theoretica
26、l axis of the cartesian coordinate system, the orientation of the slot (length) should point to the axis of the Secondary Datum Feature.32GD&T for Body EngineeringTertiary Datum FeatureThe slotted features width must be positioned on a surface with the slot width axis parallel to the primary datum p
27、lane, and controlled using the geometric control of POSITION and nominated as the Tertiary Datum Feature.33GD&T for Body EngineeringSupporting a panel on the designated Datum Target Areas, using the four way, and two way locators removes all six degrees of freedom.34GD&T for Body EngineeringStep 3Es
28、tablish GD&T Controls35GD&T for Body EngineeringCommon Terms and DefinitionsReference Pocket GuidePage 236GD&T for Body EngineeringMaterial ConditionsMMCMaximum Material ConditionLMC Least Material ConditionRFS Regardless of Feature SizeVirtual Condition37GD&T for Body EngineeringMaximum Material Co
29、nditionThe condition in which a feature of size contains the maximum amount of material within the stated limits of size.The Heaviest PartMinimum Hole Diameter (10.0)Maximum Shaft Diameter (11.0)M10.0+1.0 038GD&T for Body EngineeringLeast Material ConditionThe condition in which a feature of size co
30、ntains the least amount of material within the stated limits of size.The Lightest partMaximum Hole Diameter (11.0)Minimum Shaft Diameter (10.0)To date no application in the Feature Control Frame for this symbol has been identified in Body Engineering.L10.0+1.0 039GD&T for Body EngineeringRegardless
31、of Feature SizeThere is no symbol for Regardless of Feature Size. If a material modifier is not used then Regardless of Feature Size is assumed. The term used to indicate that a geometric tolerance or datum reference applies at any increment of size of the feature within its size toleranceRegardless
32、 of Feature Size is expensive to verify, and rarely reflects the relevant feature function, and therefore should not be used in a Body application without the agreement of the entire core team.10.0+1.0 01.040GD&T for Body EngineeringVirtual Condition A constant Boundary generated by the collective e
33、ffects of a size features specified MMC or LMC material condition and the geometric tolerance for that condition. The VIRTUAL CONDITION of features of mating parts must be matched, guaranteeing component features at their worst case for assembly will always assemble.The Virtual condition envelope is
34、 the worst condition offered to the mating part.41GD&T for Body EngineeringVirtual Condition (Shaft)Virtual condition (Shaft) = MMC + Tolerance zone value= 12.0MMCLMCM1.010.0+1.0- 0=10.0=11.0Virtual Condition42GD&T for Body EngineeringVirtual Condition (Hole)MMCLMCM1.010.0+1.0- 0= 11.0= 10.0Virtual
35、ConditionVirtual condition (Hole) = MMC - Tolerance zone value= 9.043GD&T for Body EngineeringGeometric ControlsReference Pocket GuidePage 144GD&T for Body EngineeringFeature Control Frame (Reference Pocket Guide, page 3)MAB0.5MC MGeometric characteristic symbols, the tolerance value, Material Modif
36、iers, and Datums of Reference, where applicable, are combined in a feature control frame to express a geometric tolerance.45GD&T for Body EngineeringGeometricCharacteristicSymbolMaterial Condition SymbolWhere applicableMAB0.5MC MToleranceTolerance ZoneShape where applicableDatum Reference Letters46G
37、D&T for Body EngineeringGeometric ControlsEach feature of the component must be controlled for SIZE, FORM, ORIENTATION and LOCATION.In the American National Standard there are fourteen geometric controls.Body Engineering use just three;1PERPENDICULARITY2POSITION3PROFILE47GD&T for Body EngineeringPER
38、PENDICULARITYReference Pocket GuidePage 2948GD&T for Body EngineeringPERPENDICULARITYThe main Application for PERPENDICULARITY within Body Engineering is to control a single Secondary Datum Feature of size (a hole) to be perpendicular to the Primary Datum Plane.Generally used only once within each c
39、omponent to define the secondary datum feature.Any other use of this control for other features would be an additional requirement, because PERPENDICULARITY does notimply any location 49GD&T for Body EngineeringLMCThe Cylindrical Tolerance Zone diameter is dependant on the actual feature sizeBAPERPE
40、NDICULARITYMA019.0+0.1 0A cylindrical tolerance zone perpendicular to a datum plane within which the axis of a feature must lie.50GD&T for Body EngineeringPOSITIONReference Pocket GuidePage 3351GD&T for Body EngineeringPOSITIONDefinitionPosition Tolerance ZonesZero at MMC Concept Boundary ConceptCom
41、posite Tolerance ZonesProjected Tolerance Zone52GD&T for Body EngineeringThe term to describe the perfect (theoretical exact) location of individual features in relationship with a datum reference or other feature(s). In general the POSITION control is used to locate uniform features of size, e.g. h
42、oles, shafts, slots etc.POSITION53GD&T for Body EngineeringVerificationAs with all Features of Size;First to be verified is that the top and bottom limits of size have not been violated (Taylors Principle). A full form check at the MMC and a two pointed instrument check at the LMC.Secondly the featu
43、res “Position” must be verified.GD&T does not dictate the method of verification. The decision on the gauging technique employed is the responsibility of the core team.54GD&T for Body EngineeringPosition Tolerance Zones55GD&T for Body EngineeringPositional Tolerance Zone 1(Cylindrical)20.0+1.0 0To s
44、pecify a Cylindrical Tolerance Zone, a diameter sign must precede the tolerance value, followed by the material Modifier MMC unless Regardless of Feature Size is intended.M0.5A cylindrical zone within which the centre axis of a feature of size is permitted to vary from its true (theoretically exact)
45、 position.56GD&T for Body EngineeringPositional Tolerance Zone 2(Non Cylindrical)A zone within which the centre, axis, of centre plane of a feature of size is permitted to vary from its true (theoretically exact) position.20.0+2.0 0The tolerance value is followed by the material Modifier MMC unless
46、Regardless of size is intended.To specify a total width Tolerance Zone, No diameter symbol precedes the tolerance value.M0.557GD&T for Body EngineeringBOUNDARYReference Pocket GuidePage 3758GD&T for Body EngineeringBOUNDARYIn Body Engineering controlling the centre plane of a slotted feature is rare
47、ly a priority.59GD&T for Body EngineeringAs no Diameter symbol precedes the positional tolerance, a non cylindrical zone is inferred.BOUNDARYBOUNDARYBOUNDARYWhat we are interested in is controlling the BOUNDARY of the feature.12.0 +2.0 02.0 M1.0 M5.0+1.0 060GD&T for Body EngineeringBOUNDARY 5.0 MMC
48、Width of Hole-1.0 Positional Tolerance 4.0 Wide Boundary4BOUNDARY1.0 MBOUNDARY5.0+1.0 0Virtual Condition12.0 MMC Width of Hole- 2.0 Positional Tolerance10.0 Wide Boundary102.0 M12.0 +2.0 061GD&T for Body EngineeringBOUNDARYNo portion of the slot surfaces are permitted to lie within the area describe
49、d by the Virtual Condition when the part is positioned within the Datum Reference FrameThe POSITION control + BOUNDARY controls both Location and Orientation12.0 +2.0 02.0 MBOUNDARY1.0 MBOUNDARY5.0+1.0 062GD&T for Body EngineeringBOUNDARY12.0 +2.0 02.0 MBOUNDARY2.0 MBOUNDARY5.0+1.0 0If the same Posi
50、tional Tolerance value applies to both the Length and Width limits of size, then the Feature Control Frame is separated from the Limits of Size, and points directly to the slotted feature.63GD&T for Body EngineeringBOUNDARY12.0 +2.0 02.0 MBOUNDARY5.0+1.0 0If the same Positional Tolerance value appli
51、es to both the Length and Width limits of size, then the Feature Control Frame is separated from the Limits of Size, and points directly to the slotted feature.64GD&T for Body EngineeringBOUNDARY The BOUNDARY note only applies to non cylindrical features. The POSITION control + BOUNDARY controls bot
52、h Location and OrientationIn this case the word BOUNDARY must be added below the FCF and the material Modifier MMC specified after the POSITION tolerance value.No diameter symbol precedes the tolerance value in the Feature Control FrameThe positional tolerance specified for the length may differ fro
53、m that specified for the width.To Summarise65GD&T for Body EngineeringZero at MMC conceptReference Pocket GuidePage 4466GD&T for Body EngineeringZero at MMC conceptThe Zero at MMC concept applies only to features whos sole function is CLEARANCE67GD&T for Body EngineeringM10.0L11.51.02.59.010.310.510
54、.811.21.31.51.82.29.09.09.09.09.0Actual Mating EnvelopeTolerance Zone (Dia)Virtual Condition10.0+1.5 0What is the smallest diameter hole permissible?Question?10AnswerExample of current specificationM1.0AMMBC68GD&T for Body EngineeringExample of current specificationYesAnswerQuestion?If a feature of
55、the part was measured, and the hole was found to be Dia 9.6, would this part be reject? M10.0L11.51.02.59.010.310.51.31.510.811.21.82.29.09.09.09.09.0Actual Mating EnvelopeTolerance Zone (Dia)Virtual Condition10.0+1.5 0M1.0AMMBC69GD&T for Body EngineeringExample of current specificationBut, would th
56、e rejected part be functional? Question?AnswerTo make the part acceptable we would need to change the data specification.10.0+1.5 0If the part meets the functional gauge requirements, we know the part is functional.The part has been rejected because of feature size alone.Therefore it must have been
57、manufactured to a tighter specification than that stated on the data.M1.0AMMBC70GD&T for Body EngineeringExample of current specificationWhat needs to change? Question?The specification for the hole needs to change, by adopting the “Zero at MMC” conceptAnswerM10.0L11.51.02.59.010.310.51.31.510.811.2
58、1.82.29.09.09.09.09.0Actual Mating EnvelopeTolerance Zone (Dia)Virtual Condition10.0+1.5 0M1.0AMMBC71GD&T for Body EngineeringZero at MMC concept+2.5 09.0Example:To comply with the “Zero at MMC” concept for clearance holes;The Specified value of the Feature of Size is modified to equal the Virtual C
59、ondition, i.e. (MMC-Positional Tolerance).The geometric tolerance value is incorporated into the features limits of size10.0+1.5 0M1.0AMMBCA zero tolerance is specified in the Feature Control Frame, and the material modifier MMC MUST follow the zero tolerance value.M 0AMMBC72GD&T for Body Engineerin
60、gM9.09.39.59.800.30.50.8Zero at MMC concept10.0L11.51.02.59.09.010.310.51.31.59.09.010.811.21.82.29.09.0Actual Mating EnvelopeTolerance Zone (Dia)Virtual Condition9.09.09.09.0The Zero at MMC concept gives Manufacturing the FULL range of tolerance available, and since the MMC size is now equal to the
61、 VIRTUAL CONDITION, no separate MMC feature size verification is required. (Taylors Principle)The LMC feature size must still be functionally derived and verified9.0+2.5 0M 0A B C73GD&T for Body EngineeringThe specified Feature of Size is not the target size for manufacturing.Zero at MMC conceptThe
62、tolerance available is dependant on the Feature of SizeM9.09.39.59.800.30.50.8The nearer the actual punch size is to the LMC, the larger the Tolerance of Position10.0L11.51.02.59.09.010.310.51.31.59.09.010.811.21.82.29.09.0Actual Mating EnvelopeTolerance Zone (Dia)Virtual Condition9.09.09.09.0M 09.0
63、+2.5 0VIRTUAL CONDITION & MMCLMC FEATURE SIZE74GD&T for Body EngineeringStandard Punch SizeM 0 9.0+2.5 0Punch diameter will be LMC minus 0.1mm rounded up or downM9.09.39.59.800.30.50.810.0L11.51.02.59.09.010.310.51.31.59.09.010.811.21.82.29.09.0Actual Mating EnvelopeTolerance Zone (Dia)Virtual Condi
64、tion9.09.09.09.015.2715.1715.212.7612.6612.711.511.411.4LMC-0.1mmExamplePunch Dia.75GD&T for Body EngineeringComposite Positional TolerancesReference Pocket GuidePage 4576GD&T for Body EngineeringComposite Positional Tolerances(For groups of holes)MA2.020.0+0.3 0M0.5MBMCA3 x FIX HOLESThe upper segme
65、nt is referred to as the “Pattern Locating Tolerance Zone Framework” (PLTZF)The lower segment is referred to as the “Feature Relating Tolerance Zone Framework” (FRTZF)77GD&T for Body EngineeringComposite Positional TolerancesActual HoleFeature Relating tolerance ZoneMA2.0M0.5MBMCAPattern Locating To
66、lerance Zone78GD&T for Body EngineeringComposite Positional TolerancesMA2.0M0.5MBMCA79GD&T for Body EngineeringComposite Positional TolerancesMA2.0M0.5MBMCAThe control requires that each actual feature axis must lie within the specified tolerance zones of both the upper and lower segments simultaneo
67、usly80GD&T for Body EngineeringComposite Positional TolerancesMA2.0M0.5MBMCAThe control requires that each actual feature axis must lie within the specified tolerance zones of both the upper and lower segments simultaneously25.025.081GD&T for Body EngineeringComposite Positional TolerancesIts applic
68、ation is supported by the entire core team.The control reflects the part feature manufacturing process.It will be verified in full down stream.The added-on cost to the verification process is justified by the required feature function.Before specifying this control verify that;82GD&T for Body Engine
69、eringProjected Tolerance ZoneReference Pocket GuidePage 4383GD&T for Body EngineeringProjected Tolerance ZoneThe projected tolerance zone principle should be applied to assemblies that contain mating parts of substantial thickness and are constrained with fasteners such as screws in tapped holes, st
70、uds or dowel pins (termed fixed fasteners).84GD&T for Body EngineeringFollowed by the dimension indicating the minimum height of the tolerance zoneProjected Tolerance ZoneThe PROJECTED Tolerance Zone is invoked by using the symbol in the Feature Control FramePDIRECTION OF PROJECTED ZONEM0.5P 43.2 A
71、B MCMM12 x 1.75MINOR 43.285GD&T for Body EngineeringProjected Tolerance ZoneThe Projected Tolerance Zone effectively transfers the tolerance zone from inside the tapped hole/dowel hole out into the space occupied by the body of the bolt/dowel pin after assembly86GD&T for Body EngineeringPROFILERefer
72、ence Pocket GuidePage 2087GD&T for Body EngineeringPROFILEProfile is the most versatile and probably the most powerful of the geometric Controls.88GD&T for Body EngineeringPROFILE The true profile is defined by the theoretically exact CAD model (basic dimensions).89GD&T for Body EngineeringPROFILECa
73、n be specified with or without a datum of referenceIf the control has no datum of reference then the tolerance value applies to the features true basic profile and no orientation or location is implied.If the profile control is referenced to the datum features of the component then the considered fe
74、ature is fully controlled for size, form, orientation and location90GD&T for Body EngineeringPROFILEProfile is separated into two types of controlsProfile of a LineProfile of a SurfaceThere are three methods of establishing the tolerance zoneBilateral (Default unless otherwise stated)UnilateralSpeci
75、al Case91GD&T for Body EngineeringProfile of a Line2.0The Tolerance establishes a uniform two-dimensional zone limited by two parallel zone lines extending along the length of the considered feature.The Tolerance is applied Normal/Perpendicular to the true profile at all points along the profile.The
76、 actual line element must lie within the Specified Tolerance Zone.2.0 (Bilateral)92GD&T for Body EngineeringProfile of a SurfaceThe Tolerance establishes a uniform three-dimensional zone contained between two envelope surfaces separated by the specified tolerance.The zone extends along the length an
77、d width, or circumference of the considered surface.The tolerance is applied normal to the true basic profile of the considered surface.2.02.093GD&T for Body EngineeringUnilateral Tolerance2.0TOL. APPLIES IN DIRECTION LMCHOLE2.0TOL. APPLIES IN DIRECTION MMCHOLEBASIC PROFILE2.094GD&T for Body Enginee
78、ringUnilateral Tolerance2.0TOL. APPLIES IN MATERIAL DIRECTIONMATERIAL DIRECTIONTolerance Zone95GD&T for Body EngineeringUnilateral Tolerance2.0TOL. APPLIES IN OPPOSITE MATERIAL DIRECTIONTolerance ZoneMATERIAL DIRECTION96GD&T for Body EngineeringSpecial Case2.0TOL. SPLIT:1.5 IN DIRECTION MMCBASIC PRO
79、FILEHOLE97GD&T for Body EngineeringSpecial CaseTOL. SPLIT:0.8 IN MATERIAL DIRECTION0.8 Tolerance Zone1.2 Tolerance Zone2.0MATERIAL DIRECTION98GD&T for Body EngineeringElement LinesIf, as a result of the relevant surface function it is necessary to control the surface form with a tighter tolerance th
80、an the tolerance of SIZE, FORM, ORIENTATION and LOCATION, then the following method is recommended99GD&T for Body EngineeringElement LinesA B2.0MCM0.5This Represents two separate controls;The upper FCF is the PROFILE of the Surface, for SIZE, FORM, ORIENTATION and LOCATION controlsThe Lower FCF is t
81、he ELEMENT Lines of the surface FORM control. No LOCATION or ORIENTATION is implied (No Datums of Reference)100GD&T for Body EngineeringElement LinesA B2.0MCM2.0True Basic ProfilePROFILE of a Surface 3D tolerance Boundary for SIZE, FORM, ORIENTATION and LOCATIONActual Surface must lie within Toleran
82、ce Boundary101GD&T for Body EngineeringElement LinesA B2.0MCMPROFILE of a Line 2D Tolerance Boundary located and oriented anywhere within the 3D Tolerance boundaryActual Element Line of the Surface must lie within both tolerance boundaries0.50.5102GD&T for Body EngineeringElement LinesA B2.0MCMPROFI
83、LE of a Line 2D Tolerance Boundary located and oriented anywhere within the 3D Tolerance boundaryActual Element Line of the Surface must lie within both tolerance boundaries0.50.5103GD&T for Body EngineeringElement LinesBoth profile controls contain an infinite number of points to be verified. The c
84、ore team should agree the number of points and their location to ensure consistency and repeatability in the verification process.This information is documented on the Control Plan.More information can be found in the CAD Methods web site, under the title Significant/Critical CharacteristicsTo summa
85、rise104GD&T for Body EngineeringStep 4Establishing Tolerances105GD&T for Body EngineeringEstablishing TolerancesTolerances should be derived based on the following;FunctionCostManufacturing ProcessFrom agreed generic tolerance data (see Cad Methods)Do Not “pick tolerances out of the air”, without do
86、cumented data with which to supports your decision.Do not copy tolerances blindly from previous data106GD&T for Body EngineeringDiametral FeaturesClearance HolesHoles with specific function107GD&T for Body EngineeringClearanceHolesTolerance of feature size should be derived from the generic toleranc
87、e specification, unless otherwise required, and stated on the 3D model20.0+2.5 0Zero at MMC concept appliesM A B0CMM108GD&T for Body EngineeringHoles with specific functionThe tolerance of POSITION should be derived from generic tolerance specification unless otherwise requiredM A B2.0CMM+? 020.0Fea
88、ture Size and Tolerance of Feature Size to be functionally derived and stated on the 3D model109GD&T for Body EngineeringSlotted FeaturesClearance SlotsSlots with specific function110GD&T for Body EngineeringZero at MMC concept appliesTolerance of feature width and length should be derived from the
89、generic tolerance specification, unless otherwise required, and stated on the 3D modelThe word BOUNDARY must be added under the Feature Control FrameClearance20.0+2.5 0BOUNDARYM A B0CMM111GD&T for Body EngineeringFeature size and tolerance of feature size to be functional derived and stated on the 3
90、D modelThe tolerance of POSITION should be derived from generic tolerance specification unless otherwise required.The word BOUNDARY must be added under the Feature Control FrameSlots with specific function+? 0M A B2.0CMMBOUNDARY20.0112GD&T for Body EngineeringStep 5Final Approval of GD&T on the CAD
91、Data113GD&T for Body EngineeringFinal Approval of GD&T on the CAD DataVerification required from the core team for Steps One to Four.The goal of this process should be to prevent any changes associated with incorrectly specified PMI after engineering release.This process allows input and participation from all activities affected by the data.114GD&T for Body EngineeringThank you for your attention115GD&T for Body Engineering
