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Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,GD&T for Body Engineering,*,GD&T for Body,1,GD&T for Body Engineering,Course content,课程内容,Introduction to GD&T,GD&T介绍,5 Step Process,5步方法,2,GD&T for Body Engineering,Introduction,介绍,What is GD&T,什么是GD&T,How it affects Ford Motor Company,它如何让影响福特汽车公司,3,GD&T for Body Engineering,What is GD&T,什么是GD&T,Geometric Dimensioning and Tolerancing is a technical 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 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 requirements 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。,4,GD&T for Body Engineering,What is GD&T,什么是GD&T,GDT 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 replaces 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 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。,5,GD&T for Body Engineering,Authorisation,批准,6,GD&T for Body Engineering,Application,The 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 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.,7,GD&T for Body Engineering,Application,It provides the opportunity for proper Datum selection and has the potential 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.,8,GD&T for Body Engineering,More information,9,GD&T for Body Engineering,How GD&T Relates to Ford,The correct application has the potential to;,Influence Fit and Finish,Reduce Reworks,Increase Reliability,Affects Assembly Process,Reduce cost,10,GD&T for Body Engineering,The 5 Step Process,1,2,3,4,5,11,GD&T for Body Engineering,5 Step Process,1Utilise the new Design Concept,2Establishment of the Datum Reference Frame,3Establish GD&T Controls,4Establish Tolerances,5Final Approval of GD&T on Cad Data,12,GD&T for Body Engineering,Step 1,Utilise new design concept,13,GD&T for Body Engineering,Utilise new design concept,The 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) Meetings.,14,GD&T for Body Engineering,Master Control Plan,What is the purpose of the MCP meeting in relation to PD,To 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 design for the datum reference frame, die approach, etc.,Who attends the Meeting,PD and Manufacturing, i.e. Body Engineering, DCD, Stamping, Body and Assembly.,15,GD&T for Body Engineering,Master Control Plan,When should the Meeting take place.,Initial design concept stage, knowing the components parameters such as size and function,Current methods use;,Past evidence, past experience, can sometimes hinder rather than assist the new design concept,Result of meeting,May be documented in CAD, or paper form,16,GD&T for Body Engineering,Step 2,Establish Datum Reference Frame,17,GD&T for Body Engineering,Establish Datum Reference Frame,As 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.,18,GD&T for Body Engineering,Datum Reference Frame,(Reference Pocket Guide, Page 8),Consists of a set of three mutually perpendicular planes,The reference frame exists in theory only and is not on the part,Sufficient datum features are used to position the part in relation to the Datum Reference Frame.,19,GD&T for Body Engineering,Datum Features,An actual feature of the part used to stage/position the part in the equipment for purposes of relating its geometry to the Datum Reference Frame.,20,GD&T for Body Engineering,Primary Datum Plane,Achieved by establishing a minimum of three Points to define a plane,21,GD&T for Body Engineering,Primary Datum Plane,Primary Datum Plane should be Parallel to Die Plane,22,GD&T for Body Engineering,Primary Datum Plane,When 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.,23,GD&T for Body Engineering,Supporting a panel only on the designated Datum Target Areas, effectively removes 3 degrees of freedom, i.e. 1 Linear and 2 Rotational.,24,GD&T for Body Engineering,Datum Target Areas,Datum Target Areas should wherever possible be planar and parallel to the die plane.,Primary Datum Plane,25,GD&T for Body Engineering,Datum Target Areas,Dedicated Datum Target Areas makes both the part, and gauge/fixture more robust, cost effective and Improves repeatability,26,GD&T for Body Engineering,Secondary Datum Feature,Generally a Datum Feature of Size is used , i.e. Single circular Hole, positioned on a surface that is parallel to the Primary datum Plane, and is ultimately used as a four way locator.,27,GD&T for Body Engineering,Secondary Datum Feature,Controlled relative to the Primary Datum Plane using the Geometric control PERPENDICULARITY.,28,GD&T for Body Engineering,Secondary Datum Feature,The intersection of the derived axis of the feature perpendicular to the Primary Datum Plane, and the design side of the component is the local origin of all basic dimensions; 0,0,0,29,GD&T for Body Engineering,Supporting a panel on the designated Datum Target Areas, and using the four way locator removes another 2 Linear degrees of freedom, resulting in all 3 Linear, and 2 Rotational degrees of freedom constrained.,30,GD&T for Body Engineering,Tertiary Datum Feature,Generally the width of a Slotted Feature of Size is used as a two way locator.,31,GD&T for Body Engineering,Tertiary Datum Feature,To eliminate tolerance of Datum Shift on one of the theoretical axis of the cartesian coordinate system, the orientation of the slot (length) should point to the axis of the Secondary Datum Feature.,32,GD&T for Body Engineering,Tertiary Datum Feature,The slotted features width must be positioned on a surface with the slot width axis parallel to the primary datum plane, and controlled using the geometric control of POSITION and nominated as the Tertiary Datum Feature.,33,GD&T for Body Engineering,Supporting a panel on the designated Datum Target Areas, using the four way, and two way locators removes all six degrees of freedom.,34,GD&T for Body Engineering,Step 3,Establish GD&T Controls,35,GD&T for Body Engineering,Common Terms and Definitions,Reference Pocket Guide,Page 2,36,GD&T for Body Engineering,Material Conditions,MMCMaximum Material Condition,LMC Least Material Condition,RFS Regardless of Feature Size,Virtual Condition,37,GD&T for Body Engineering,Maximum Material Condition,The condition in which a feature of size contains the maximum amount of material within the stated limits of size.,The Heaviest Part,Minimum Hole Diameter (10.0),Maximum Shaft Diameter (11.0),M,10.0,+1.0,0,38,GD&T for Body Engineering,Least Material Condition,The condition in which a feature of size contains the least amount of material within the stated limits of size.,The Lightest part,Maximum 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.,L,10.0,+1.0,0,39,GD&T for Body Engineering,Regardless of Feature Size,There 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 tolerance,Regardless 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,+1.0,0,1.0,40,GD&T for Body Engineering,Virtual Condition,A constant Boundary generated by the collective effects 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 the worst condition offered to the mating part.,41,GD&T for Body Engineering,Virtual Condition (Shaft),Virtual condition (Shaft) = MMC + Tolerance zone value,=,12.0,MMC,LMC,M,1.0,10.0,+1.0,- 0,=10.0,=11.0,Virtual Condition,42,GD&T for Body Engineering,Virtual Condition (Hole),MMC,LMC,M,1.0,10.0,+1.0,- 0,= 11.0,= 10.0,Virtual Condition,Virtual condition (Hole) = MMC - Tolerance zone value,=,9.0,43,GD&T for Body Engineering,Geometric Controls,Reference Pocket Guide,Page 1,44,GD&T for Body Engineering,Feature Control Frame,(Reference Pocket Guide, page 3),M,A,B,0.5,M,C,M,Geometric characteristic symbols, the tolerance value, Material Modifiers, and Datums of Reference, where applicable, are combined in a feature control frame to express a geometric tolerance.,45,GD&T for Body Engineering,Geometric,Characteristic,Symbol,Material Condition Symbol,Where applicable,M,A,B,0.5,M,C,M,Tolerance,Tolerance Zone,Shape where applicable,Datum Reference Letters,46,GD&T for Body Engineering,Geometric Controls,Each 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;,1PERPENDICULARITY,2POSITION,3PROFILE,47,GD&T for Body Engineering,PERPENDICULARITY,Reference Pocket Guide,Page 29,48,GD&T for Body Engineering,PERPENDICULARITY,The 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 component 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,49,GD&T for Body Engineering,LMC,The Cylindrical Tolerance Zone diameter is dependant on the actual feature size,B,A,PERPENDICULARITY,M,A,0,19.0,+0.1,0,A cylindrical tolerance zone perpendicular to a datum plane within which the axis of a feature must lie,.,50,GD&T for Body Engineering,POSITION,Reference Pocket GuidePage 33,51,GD&T for Body Engineering,POSITION,Definition,Position Tolerance Zones,Zero at MMC Concept,Boundary Concept,Composite Tolerance Zones,Projected Tolerance Zone,52,GD&T for Body Engineering,The 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. holes, shafts, slots etc.,POSITION,53,GD&T for Body Engineering,Verification,As 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 features “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.,54,GD&T for Body Engineering,Position Tolerance Zones,55,GD&T for Body Engineering,Positional Tolerance Zone 1,(Cylindrical),20.0,+1.0,0,To specify 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.,M,0.5,A cylindrical zone within which the centre axis of a feature of size is permitted to vary from its true (theoretically exact) position.,56,GD&T for Body Engineering,Positional 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,+2.0,0,The tolerance value is followed by the material Modifier MMC unless Regardless of size is intended.,To specify a total width Tolerance Zone, No diameter symbol precedes the tolerance value.,M,0.5,57,GD&T for Body Engineering,BOUNDARY,Reference Pocket GuidePage 37,58,GD&T for Body Engineering,BOUNDARY,In Body Engineering controlling the centre plane of a slotted feature is rarely a priority.,59,GD&T for Body Engineering,As no Diameter symbol precedes the positional tolerance, a non cylindrical zone is inferred.,BOUNDARY,BOUNDARY,BOUNDARY,What we are interested in is controlling the BOUNDARY of the feature.,12.0,+2.0,0,2.0,M,1.0,M,5.0,+1.0,0,60,GD&T for Body Engineering,BOUNDARY,5.0 MMC Width of Hole-1.0 Positional Tolerance,4.0 Wide Boundary,4,BOUNDARY,1.0,M,BOUNDARY,5.0,+1.0,0,Virtual Condition,12.0 MMC Width of Hole- 2.0 Positional Tolerance,10.0 Wide Boundary,10,2.0,M,12.0,+2.0,0,61,GD&T for Body Engineering,BOUNDARY,No portion of the slot surfaces are permitted to lie within the area described by the Virtual Condition when the part is positioned within the Datum Reference Frame,The POSITION control + BOUNDARY controls both Location and Orientation,12.0,+2.0,0,2.0,M,BOUNDARY,1.0,M,BOUNDARY,5.0,+1.0,0,62,GD&T for Body Engineering,BOUNDARY,12.0,+2.0,0,2.0,M,BOUNDARY,2.0,M,BOUNDARY,5.0,+1.0,0,If the same Positional 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.,63,GD&T for Body Engineering,BOUNDARY,12.0,+2.0,0,2.0,M,BOUNDARY,5.0,+1.0,0,If the same Positional 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.,64,GD&T for Body Engineering,BOUNDARY,The BOUNDARY note only applies to non cylindrical features.,The POSITION control + BOUNDARY controls both Location and Orientation,In 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 Frame,The positional tolerance specified for the length may differ from that specified for the width.,To Summarise,65,GD&T for Body Engineering,Zero at MMC concept,Reference Pocket Guide,Page 44,66,GD&T for Body Engineering,Zero at MMC concept,The Zero at MMC concept applies only to features whos sole function is CLEARANCE,67,GD&T for Body Engineering,M,10.0,L,11.5,1.0,2.5,9.0,10.3,10.5,10.8,11.2,1.3,1.5,1.8,2.2,9.0,9.0,9.0,9.0,9.0,Actual Mating Envelope,Tolerance Zone (Dia),Virtual Condition,10.0,+1.5,0,What is the smallest diameter hole permissible?,Question?,10,Answer,Example of current specification,M,1.0,A,M,M,B,C,68,GD&T for Body Engineering,Example of current specification,Yes,Answer,Question?,If a feature of the part was measured, and the hole was found to be Dia 9.6, would this part be reject?,M,10.0,L,11.5,1.0,2.5,9.0,10.3,10.5,1.3,1.5,10.8,11.2,1.8,2.2,9.0,9.0,9.0,9.0,9.0,Actual Mating Envelope,Tolerance Zone (Dia),Virtual Condition,10.0,+1.5,0,M,1.0,A,M,M,B,C,69,GD&T for Body Engineering,Example of current specification,But, would the rejected part be functional?,Question?,Answer,To make the part acceptable we would need to change the data specification.,10.0,+1.5,0,If 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 manufactured to a tighter specification than that stated on the data.,M,1.0,A,M,M,B,C,70,GD&T for Body Engineering,Example of current specification,What needs to change?,Question?,The specification for the hole needs to change, by adopting the “Zero at MMC” concept,Answer,M,10.0,L,11.5,1.0,2.5,9.0,10.3,10.5,1.3,1.5,10.8,11.2,1.8,2.2,9.0,9.0,9.0,9.0,9.0,Actual Mating Envelope,Tolerance Zone (Dia),Virtual Condition,10.0,+1.5,0,M,1.0,A,M,M,B,C,71,GD&T for Body Engineering,Zero at MMC concept,+2.5,0,9.0,Example:,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 Condition, i.e. (MMC-Positional Tolerance).,The geometric tolerance value is incorporated into the features limits of size,10.0,+1.5,0,M,1.0,A,M,M,B,C,A zero tolerance is specified in the Feature Control Frame, and the material modifier MMC,MUST,follow the zero tolerance value.,M,0,A,M,M,B,C,72,GD&T for Body Engineering,M,9.0,9.3,9.5,9.8,0,0.3,0.5,0.8,Zero at MMC concept,10.0,L,11.5,1.0,2.5,9.0,9.0,10.3,10.5,1.3,1.5,9.0,9.0,10.8,11.2,1.8,2.2,9.0,9.0,Actual Mating Envelope,Tolerance Zone (Dia),Virtual Condition,9.0,9.0,9.0,9.0,The Zero at MMC concept gives Manufacturing the FULL range of tolerance available, and since the MMC size is now equal to the VIRTUAL CONDITION, no separate MMC feature size verification is required. (Taylors Principle),The LMC feature size must still be functionally derived and verified,9.0,+2.5,0,M,0,A,B,C,73,GD&T for Body Engineering,The specified Feature of Size is not the target size for manufacturing.,Zero at MMC concept,The tolerance available is dependant on the Feature of Size,M,9.0,9.3,9.5,9.8,0,0.3,0.5,0.8,The nearer the actual punch size is to the LMC, the larger the Tolerance of Position,10.0,L,11.5,1.0,2.5,9.0,9.0,10.3,10.5,1.3,1.5,9.0,9.0,10.8,11.2,1.8,2.2,9.0,9.0,Actual Mating Envelope,Tolerance Zone (Dia),Virtual Condition,9.0,9.0,9.0,9.0,M,0,9.0,+2.5,0,VIRTUAL CONDITION & MMC,LMC FEATURE SIZE,74,GD&T for Body Engineering,Standard Punch Size,M,0,9.0,+2.5,0,Punch diameter will be LMC minus 0.1mm rounded up or down,M,9.0,9.3,9.5,9.8,0,0.3,0.5,0.8,10.0,L,11.5,1.0,2.5,9.0,9.0,10.3,10.5,1.3,1.5,9.0,9.0,10.8,11.2,1.8,2.2,9.0,9.0,Actual Mating Envelope,Tolerance Zone (Dia),Virtual Condition,9.0,9.0,9.0,9.0,15.27,15.17,15.2,12.76,12.66,12.7,11.5,11.4,11.4,LMC,-0.1,mm,Example,Punch Dia.,75,GD&T for Body Engineering,Composite Positional Tolerances,Reference Pocket GuidePage 45,76,GD&T for Body Engineering,Composite Positional Tolerances,(For groups of holes),M,A,2.0,20.0,+0.3,0,M,0.5,M,B,M,C,A,3 x FIX HOLES,The upper segment 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),77,GD&T for Body
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