# 537 Geometric Dimensioning & Tolerancing (GD&T) Applications and Tolerance Stacks

For Whom Intended Course 537 is an advanced course for design engineers, drafters, manufacturing engineers, quality engi­neers and others involved with tolerance analysis or drawing re­view. Anyone who needs to understand how to apply geo­metric tolerancing and perform tolerance analysis will greatly benefit.

Brief Course Descrption People may understand the fun­da­men­tals of GD&T such as datums, position with MMC and RFS mod­ifiers, parallelism, profile etc. However they may lack the intimate know­ledge of how to expertly apply geometric tolerancing and perform toler­ance stacks and analysis to clearly define and optimize their pro­duct design.

Tolerance stacks are an important tool used to evaluate the variable fea­tures and dimensions of a single part or an assembly of parts. Tol­er­ance stacks are used in the calculation of fits and fit-ups, tolerance ac­cumulation/allocation, datum selection and the use of feature mod­ifiers and datum modifiers.

This course teaches personnel how to apply GD&T and perform toler­ance stacks using a series of case study problems including sheet metal, machinings, plastic parts, castings etc. The entire course is 17 units; organizations may select problems as appro­priate to customize the program to meet students’ needs.

The Tolerance stacks section is designed to teach students how to cal­cu­late linear, axial and orientation stacks using parts toler­anced with ei­ther plus/minus or geometric tolerancing. Student hands-on exercises con­sist of a variety of case studies on both details and assemblies.

The remaining units contain case study examples where stu­dents must estab­lish datum reference frames and apply geo­metric toler­ancing based on clearly defined functional re­quire­ments. After­wards, they per­form tolerance stacks to ensure de­sign re­quire­ments are met. The prob­lems grad­ually in­crease in com­plexity. Students will apply con­cepts learned in early les­sons to progress to later lessons. Applications may be se­lected to match the client organization’s products and processes.

Lessons in the Stacks section may be alternated with lessons in the Ap­plications section, to provide variety and make the stacks cal­cu­lations less taxing. This also demonstrates that pro­per selec­tion of the da­tums, as well as position and profile values on individual parts, have a great effect on the tolerance accumulation in the overall assembly.

This program provides creative procedures using tables and sim­ple for­mu­las to break the most complex problems into simpler seg­ments. It gives tips and suggestions on how and when to add up form, orien­tation and location variations due to varying manu­facturing processes.

Diploma Programs: This course may be used as an elective for TTi's Metrology/Calibration Specialist (MSC), or Mechanical Design Specialist (MDS) Diploma Programs, or for any other TTi specialist diploma program.

Related Courses: For an introduction to GD&T, see TTi Course 535, Geometric Dimensioning and Tolerancing (GD&T) to ASME Y14.5–2009. Course 536, Inter­me­diate/Advanced GD&T, picks up where Course 535 leaves off.

Prerequisites: Students should have completed TTi course 535, or have equivalent experience.

Text  Each student will receive a course work­book, GeoTol Appli­ca­tions and Tolerance Stacks, by Scott Neumann and Al Neumann, 2012.

Certificate and CEUs Upon suc­cessful course completion, each partici­pant re­ceives a certi­ficate of completion and one Con­tinu­ing Edu­ca­tion Unit (CEU) for every ten class hours.

## Course Outline

### Tolerance Stacks Section

• Plus/Minus Stacks
• Bilateral tolerances
• Unequal Tolerances Example
• Limit Tolerances
• Spool Exercise
• 4-part, 7-part Assembly Exercises
• Profile Detail Stacks
• Form/Orientation Tolerance Considerations
• Hub, Hole Bar & Shaft Exercises
• Profile Assembly Stacks
• Form and Orientation Tolerance Considerations
• Cage Assembly
• Loose Fit and Shaft Assembly Exercises
• Boundary Detail Stacks
• Calculating MMB/LMB
• Position RFS/MMC/LMC Boundaries
• Profile and Runout Boun­dary Exercises
• Position MMC and LMC Boundary Exercises
• Stack Table Data Entry Exercise
• Hole Edges and Hole-to-Edge Stack Exercises
• Boundary Assembly Stacks
• Boundary Formula Review
• Cap and Sleeve/RFS/MMC Exercises
• Alignment Assembly Pin to Cage Exercise
• Stack Table Datum Shift and Size Only (So) Exercises
• Datum Modifier Evaluation Exercise
• Cap/Sleeve MMB Datum and MMC Feature/Datum Exercises
• Hub Assembly and Pilot Tube Assembly Exercises
• Switch Assembly Exercise
• Orientation Stacks
• Hub and Poker Pin Exercises

### Applications Section

• Introduction to Design Applications:
• Floating/Fixed Fastener Formulas
• Projected Tolerance Zone
• Specific Design Applications
• Grommet Assembly
• Powder Case Assembly
• Fuel Cooler Bracket
• Valve Assembly
• Step Bracket Assembly
• Regulator Mounting Bracket
• Optic Connector Assembly
• Mixer Assembly
• Alternator Bracket