Of course, index Cpm is used as well. I think 6 sigma is good program, when it includes advanced quality tools like robust design. I only wanted to say we cannot always rely on capability indices values. In addition, increased Cpk may bring higher unit manufacturing costs.
Robust design seeks always low-cost solution for variation reduction.
And robust design has not as an issue tolerances, but the target value. So if 6 sigma takes into consideration target value philosophy, it is Ok. Dr Pavel Blecharz senior lecturer in TQM Technical University of Ostrava, Czech Republic Quality Management Institute - QMI,v.o.s. WebForum created by Storm 1996.