## Tolerance Stack Analysis

### Course Description

Tolerance Analysis is an information packed course that will provide participants with the analytical tools needed to:

• Set up a tolerance problem
• Determine the 100% tolerance stack-up in an assembly
• Analyze fixed and floating fastener assemblies
• Use statistical tolerancing

### Audience

• Mechanical Engineers
• Design Engineers
• Manufacturing Engineers
• Anyone who is required to determine assembly tolerances.

### Emailpaulette@pyyoungassociates.com

Phone
1 (650) 967-2700

Address
P.O. Box 2103
Sunnyvale, CA 94087-0103

### Course Outline:

The Basics
Identify factors pertinent to stack-up analysis
Designate positive and negative routes
Position each part for a worst-case analysis
Calculate mean dimensions and equal bilateral tolerances 5. Calculate virtual and resultant condition boundaries

Box Assembly
Apply basic stack-up analysis to a box assembly
Draw loop analysis diagram for the box assembly
Designate positive and negative routes
Calculate mean dimensions and equal bilateral tolerances
Calculate MAX and MIN GAP

Tolerance Stack-Up Analysis for Feature of Size
Perform a loop analysis
Determine the start and end points
Graph values on a loop diagram

Tolerance Stack-Up Analysis for Assemblies with Plus and Minus Tolerancing
Calculate airspaces and interferences
Alternative method of Analysis

Tolerance Stack-Up Analysis for a Floating Fastener Assembly
Calculate resultant and virtual conditions
Convert all dimensions to equal bilateral tolerances
Mix widths and diameters in a numbers chart
Graph the numbers into a tolerance stack-up diagram
Determine all unknown gaps in a five-part assembly

Tolerance Stack-Up Analysis for a Fixed Fastener Assembly
Calculate overall housing requirements
Calculate MIN and MAX GAPS within the assembly

The Theory of Statistical Probability
Convert an arithmetical to a statistical tolerance
Use the Root Sum Squares (RSS) formula
Determine the tolerance statistically likely to be consumed
Compare the statistical tolerance to the arithmetical tolerance
Calculate the percentage each tolerance may be increased
Use a correction factor as a multiplier
Reintegrate the Statistical Tolerance into the assembly