The strategy for the implementation of six sigma quality in current product manufacturing is quite different form the strategy of setting and achieving six sigma quality goals for new products. Half of the six sigma ratio, the product specifications, is usually fixed for current products, since the cost of altering them and retesting the product designs would be too prohibitive. Reaching six sigma for current products that were designed without a formal quality program is difficult, especially since the other half of the six sigma ratio, that of reducing variability, is the only option available. For new products, the opportunity to influence both sides of the six sigma ratio is much greater; hence, achieving six sigma is easier. This chapter will focus on achieving six sigma quality for both current and new products. The topics discussed in this chapter are:
1. Current product six sigma strategy. In Section 8.1, the strategy to attain six sigma for current products is developed by gradually using different tools as the manufacturing quality improves with time. Examples will be given in several manufacturing areas to demonstrate the evolution of quality in manufacturing.
2. Transitioning new product development to six sigma. In Section 8.2, the efforts required by the manufacturing and design teams to quantify the steps necessary to attain six sigma in new products are shown. Some of these efforts include process capability studies, whereas others are more qualitative and involve design guidelines for reducing defects in new designs
3. Determining six sigma quality in different design disciplines. Six sigma is a tool for both design and manufacturing. Previous chapters have shown how to determine six sigma from the product specifications and manufacturing variability, as well from manufacturing reject rates. In Section 8.3, designs from different disciplines will be analyzed for six sigma quality and their capability calculated with detailed examples.
4. Using six sigma quality for new product introduction. In Section 8.4, the use of six sigma to determine overall new product introduction strategy and the use of quality tools to help achieve six sigma quality and defect removal goals will be shown at the product and system levels.