Using Six Sigma Concepts in the Engineering Process at Automotive Suppliers: Analysis of an Acoustical Test Bench 2007-01-0530

Six Sigma was developed by Motorola in the 1980s as an enhancement of their Total Quality Management (TQM) approach focusing on quality improvement. Companies such as General Electric (GE) developed the concept even further and extended the application of Six Sigma tools to their entire business, including the development of new products, with a focus on both financial gain and customer satisfaction. Six Sigma, however, also offers a rigorous, data-driven procedure for process and product improvement and for the development of new products and processes using proven methods and tools taken from the Quality Management and Quality Engineering toolbox. Integration into the existing engineering culture and the application of these tools and concepts to a typical application at a leading global exhaust system supplier are outlined in this paper.

The procedure which is used for measuring the surface radiated noise is analyzed in detail by the principles of Six Sigma. This measurement procedure is a standard application used in the development process for exhaust systems of vehicles.

Reproducibility and repeatability of these measurements had been poor due to the differences in temperature and mass flow through the system and variations in the combustion process. Changes within 1-2 dB improvement were not previously covered by this test procedure without additional measures. The process, therefore, was checked using a test rig analysis based on Six Sigma methods. It showed the basic problem and gave proposals for improvements, which have now been integrated within the development process.

The physical phenomena, procedures and improved testing processes are outlined in this paper.