A Holistic Approach to Manufacturing System Design in the Defense Aerospace Industry

This thesis presents the first validation activity of this framework. Fourteen case studies spanning assembly operations from major aerostructures, electronics, launch vehicles and spacecraft were used to test the hypothesis that a firm that followed the process outlined by the framework would design a more effective manufacturing system as measured by actual performance compared to the planned performance. In each case study, the actual manufacturing system design process used by the site was either captured in real-time as the manufacturing system was being designed or retrospectively and a framework congruence value was determined. This value, obtained through a structured survey/interview process, is a measure of how closely the manufacturing system design process proposed by the framework matches the processes actually followed by the case studies.

This framework congruence value was compared to a performance metric of the resulting manufacturing system. The performance measure used in this study was the actual/planned performance of the manufacturing system. An actual/planned performance measure of 1 means that the system was able to assemble the product in the number of days planned, while a performance measure of 3 would mean that it actually took 3 times longer to assemble the
product than planned. This performance measure was appropriate for all the assembly operations contained in this data set and allowed the figures to be normalized for comparison.