The Quality-Based System Design Process

The quality system review can be used to drive quality into the new product design process. In most instances, quality goals for new products and systems are given as six sigma or Cpk values for individual parts and processes, with design engineering providing the product specifications while the manufacturing operations are calculating the process averages and variability in order to meet the six sigma goal.

This six sigma quality assessment methodology works well at the micro level, with individual product part or component specifications and their manufacturing steps. It is the purpose of this chapter to outline a procedure for using this methodology at the macro level, with multiple specifications and designs leading to the system performance requirements. The six sigma quality-based design methodology could also be used for systems architecture and partitioning of hardware and software, design trade-offs, manufacturing and test plans, and monitoring the systems design performance relative to its requirements and specifications.

The principles, tools, and examples used in this quality-based system design for six sigma methodology were developed for high-technology companies that are pioneering the use of design for quality methods to augment their traditional design process. They have been able to successfully develop cost-effective new products and systems using this methodology for allocation of module specifications and the trade-off of defects generated through partially conforming designs versus the cost of removing these defects in PCB manufacturing.