Circle Grid Analysis

1-Day Course

In this workshop you will learn how to perform and interpret circle grid and thinning strain analysis. Through exercises with actual parts you will be performing hands-on circle grid and thinning measurements. You will review the limitations and guidelines for the use of circle grid and thinning measurements. Also included is the measurement and application of surface stretch analysis for outer panels.


Tooling Supervisors, Tooling and Quality Engineers, and Tool and Die Makers.


1.0 Overview of Thinning Strain and Circle Grid Analysis

1.1 Understanding Thinning Strain and Circle Grid Analysis

1.2 Applications of Thinning Strain and Circle Grid Analysis

1.3 What is the Difference between Thinning Strain Analysis and Circle Grid Analysis

1.4 Procedure for Thinning Strain and Circle Grid Analysis

1.5 Other Uses for Thinning Strain and Circle Grid Analysis

2.0 Fundamentals of Thinning Strain Analysis (TSA)

2.1 Establishing the Thinning Limit

2.2 Thinning Strain

2.3 Calculating Thinning Strain

Exercise: Calculating Thinning Strain

2.4 Measuring Thickness

2.5 Finding 'Hot Spots'

2.6 Highlighting Areas for Circle Grid Analysis

3.0 Fundamentals of Circle Grid Analysis

3.1 Types of Circle Grids

3.2 Methods for Applying Circle Grids

3.3 Major Strain and Minor Strain

Exercise: Calculating Major and Minor Strain

3.4 Measuring Circles

Exercise: Measuring Major and Minor Strain with Mylar

3.5 Recording and Plotting Measured Data

3.6 Introduction to Forming Limit Diagrams

4.0 Forming Limit Diagrams

4.1 Why do we use Forming Limit Diagrams?

4.2 Shape and Position of Steel Forming Limit Curves

Exercise: Finding FLD0 by the Table Method and the Calculation Method

4.3 Shape and Position of Aluminum Forming Limit Curves

4.4 Safety Margin

5.0 Surface Stretch Analysis

5.1 Where to use Surface Stretch Analysis

5.2 Target Strain

5.3 Dent Resistance

5.4 Stiffness

6.0 Results

6.1 Interpretations of Results

6.2 Limitations of TSA, CGA and Surface Stretch Analysis

6.3 Sample Report

6.4 Corrective Action