Producibility Elements Highlighted:
Perform a Complexity Analysis
Perform Trade Studies on Alternative Product and Process
At Raytheon TI Systems in Dallas, Texas, a program contained a number of detailed and complex housings that had to be fabricated in the metal shop. The design engineer had called out a specific type of tolerance on the housing, based on performance requirements, that forced the use of costly jig bore machinery.
Using Process Capability Analysis (PCA), the design engineer was shown an alternate tolerance and its required values to produce the desired results using a Computerized Numerical Control machine. This suggested change was analyzed to ensure performance was not compromised if incorporated in the design. Since it was proven to have no degradation in performance, the new tolerance scheme was incorporated. The resulting cost savings based on higher
yields and lower defect rates for the new process was $550 per unit. Extended across the life of the project, this generated a cost avoidance of over $4M.
What was not captured in this analysis were the hidden costs associated with the capital equipment. To produce the design as originally toleranced, added jig bore machine capacity would have had to be obtained to meet the program's requirements. Whether obtained through capital purchases or subcontracting work outside, this cost was estimated to be significant.
This effort highlighted the value of performing PCA, not only to ensure that designs can be manufactured cost-effectively and defect-free, but also to eliminate hidden costs that may not become evident until much later in the program. Moreover, this one tolerance callout on one design, while representing only $550 savings per unit, is an indication of other significant opportunities across all designs. The application of PCA across program life-cycles can accumulate the seemingly small per unit savings and hidden costs and quickly add up to millions of dollars in cost avoidance.