Production AST with Computers Using the Taguchi Method - Reprinted from Environmental Stress Testing Experiment Using the Taguchi Method, IEEE Transactions on Components, Packaging, and Manufacturing Technology, Part A, Vol. 18, No.1, pp. 39, with permission from the author and the IEEE, 1995.

Manufacturing process improvements which increase productivity, decrease test process time, and improve customer satisfaction are highly desirable in today's marketplace. The application of environmental stress screening (ESS), i.e, Production AST, is a method of achieving these improvements. ESS is the application of stresses applied beyond product specification limits in order to find latent product defects. Utilizing ESS achieves increased robustness and lowers infant mortality.

An experiment was performed to identify the significance or relevancy of the selected stresses for application in the printed wiring assembly (PWA) production process by using a statistically significant controlled method. The design of experiments statistical approach (analysis of variance) is applied, combined with the Taguchi two-level, seven-factor design method.

This experiment concentrated on three stresses?-?temperature cycling, random vibration, and power cyling?-?and two diagnostic levels?-?a prom-based (programmable memory chip), power-on self test (POST), and a functional diagnostic test suite, contained on disk storage.

This was not an optimization experiment. Once the significance to the production process is identified, future optimizing of temperature cycling, power cycling, and vibration screens will be conducted. Also, voltage margining was not included to reduce the complexity of the experiment-treatment factors and interactions. Experimental results and conclusions on the effectiveness of different stress regimens are presented in this chapter.

• Introduction

• Objectives

• Stress Overview

• Stress Screen Designs

• Experiment Overview

• The Taguchi Method

• Response Variable Results and Conclusions of the Taguchi Experiment

• Intra-Experiment Summary

• Taguchi Method Conclusion

• Terms

• Acknowledgments

• References