M O D U L A R   T O L E R A N C I N G   C O U R S E   # 2 Introduction to GD&T   |   Advanced GD&T Applications in Design   |   Course Outline ELEMENTS OF GEOMETRIC DIMENSIONING AND TOLERANCING by E.A. Lehtihet, Ph.D. INTRODUCTION What is ASME Y14.5M-1994 ? Scope and benefits Basic considerations Concept of size and tolerance zone Features and features of size Material condition modifiers Feature control frames Rules FORM CONTROLS Flatness Aplication to a planar surface Verification principle Straightness Application to a feature Application to a line element Application to a feature of size Application @ MMC Gaging principle with MMC modifier Application on a unit length basis Roundness Application to circular and conical features Application to spherical features Evaluation and verification principle Cylindricity Application to a cylinder Evaluation and verification principle ORIENTATION CONTROLS Scope of orientation control Perpendicularity Application to a surface Evaluation and verification principle Application to a feature of size ( slot ) Application to a feature of size ( shaft ) Virtual condition Application to a cylindrical feature of size @ MMC Preserving perfect form @ MMC Industrial example application and implications Functional gaging examples Parallelism Application to a feature: Example #1 Evaluation and verification principle Application to a feature : Example #2 Application to a feature of size : Example #1 Application to a feature of size : Example #2 Application @ MMC Control in two directions Functional gaging examples Angularity Application to a feature Evaluation and verification principle Application to a feature of size Refining the tolerance zone LOCATION CONTROLS Scope and importance of location controls Position tolerance Coordinate versus true position tolerance Position tolerance specification Uderstanding the datum reference system Position tolerance specification @ MMC Functional gaging principle Position tolerance specification RFS Verification principle Use of datum features of size RFS Use of datum features of size @ MMC Industrial example : Application and implications Feature of size datum with form constraint Application to coaxial features of size Application @ LMC Zero position tolerance @ MMC Groups of features, multiple patterns, common datum system Composite position tolerance Basic specification and interpretation Evaluation and verification principles Application to other patterns Specification of a secondary datum Two single segment control frames Verification and manufacturing yield implications Bidirectional position tolerance specification Bidirectional specification with polar coordimates Position tolerance of a slot @ MMC Position tolerance of elongated holes Circular configuration of slots Concentricity tolerance Basic interpretation and implications Application to a cylindrical feature Evaluation and verification principles Effect of form errors on concentricity tolerances Concentricity and coaxiality Symmetry tolerance Position tolerance of a symmetrical feature of size Introducing the MMC modifier Example of use and interpretation PROFILE CONTROLS Scope of controls Profile of a line Profile of a surface Application example with mating parts Evaluation and verification principle RUNNOUT CONTROLS Scope of controls Circular runnout Toatal runnout Evaluation and verification principles Comparison with position and concentricity ADDITIONAL DATUM CONCEPTS Datum target points Datumtarget lines Datumtarget areas Example applications Inclined datum feature Orientation of two datum planes through a hole Effect of material condition and datum precedence Dealing with datum shifts Design versus manufacturing datums Change of datum computations Change of datum computations for unidirectional dimensions Simple change of datum computations for orientation tolerances Simple change of datum computations for location tolerances Complex change of datum problems APPLICATION TOOLS AND TECHNIQUES POSITION TOLERANCE ANALYSIS PROCEDURE Basic methodology for assembly problems Geometric reference frames Tolerance diagrams Virtual components Assembly requirements The critical review checklist SOLVING POSITION TOLERANCING PROBLEMS Floating fastener assembly formulation Floating fastener assembly application problem and solution Projected tolerance zone Fixed fastener assembly formulation Fixed fastener assembly application problem and solution Floating fastener assembly with counterbore formulation Floating fastener assembly with counterbore application and solution Fixed fastener assembly with counterbore formulation Fixed fastener assembly with counterbore application and solution Mating part design application #1 Mating part design application #2 Preserving minimum wall thickness: Formulation and solution Locating fastening holes: Formulation and solution Part / Mating cavity design using profile and position tolerances Part / Mating cavity design with composite position tolerance SOLVING DATUM SYSTEM PROBLEMS FOR ASSEMBLY Use of datum systems in design Restaining the egrees of freedom of a solid Five (5) commonly used datum systems in design Analysis of each datum system type ( for each type ) Function of the datum system Geometric control Generic dimensioning and tolerancing scheme Functional requirements for accuracy and precision Functional equations Solution methodology Application examples #1 & #2 DIMENSIONAL ANALYSIS OF LENGTHS & TOLERANCE STACKS The tolerance stack problem in assemblies Scope of the methodology A brief reminder on vectors The vector loop method for tolerance analysis Useful rules to develop loops in assembly problems Application to assembly problems Material condition equations Manipulating upper and lower deviations Example application #1 Tolerance stack equations Example application #2 Putting it all together : A case study GEOMETRIC ANALYSIS FOR ASSEMBLY Some fundamental principles of tolerance design Mapping functional requirements into functional dimensions Mapping functional requirements into functional tolerances Case study This page has been accessed [an error occurred while processing this directive] times since July 14, 1999. site design by oxygenesis design / 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