## 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.

### Contact Information

**Email**

paulette@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