Statistical Analysis Applied to Structural Attachment Bosses

A process evaluation was made as part of a continuing program to identify and control the root causes leading to low stripping torque in automotive structural attachment bosses. The first phase of this program was presented jointly by Inland Division. General Motors Corporation and ARCO Chemical at the 1987 SAE meeting. Subsequent evaluations have broadened the scope of materials evaluated and the laboratory evaluations have lead to the study of the commercial molding process.

A methodical approach was taken and statistical process control techniques were applied in addressing the possible causes contributing to low stripping torque.

The evaluation program identified the bosses most likely to have stripping problems, tested for correlations with measured molding parameters and effectively identified the future direction of the program.