An improved methodology for evaluating the producibility of partially specified part designs

Within the concurrent engineering (CE) paradigm, products must be designed in light of downstream lifecycle preferences and capabilities. One CE challenge is the need to estimate the downstream implications of partially specified part designs as early as possible in the design cycle. In this research, the hierarchical evaluation methodology for early design (HEMED) was developed to address this challenge for the fixed-principle design environment in the piece-part manufacturing industry. A prescriptive decision-modelling approach was used to develop this methodology. HEMED models a company's preferences and priorities using a weighted hierarchy of business objectives, and it uses utility scoring logic to evaluate a part design's performance relative to these priorities. Utility scores are aggregated in a bottom-up manner to generate the part design's HEMED rating, which consists of both a score and its associated uncertainty factor for each objective in the hierarchy. A prototype, proof-of-concept HEMED design-rating system was implemented and verified at a local aerospace manufacturing company. Several of the company's experienced production engineers believed that the HEMED prototype, while limited in scope, accurately represented their organization's preferences and priorities. They also believed that the prototypes test part ratings were accurate compared to their first-hand experience with these parts. HEMED was also compared to the other documented and validated early design evaluation methodology by a total of 28 engineers and technical managers from two aerospace manufacturing companies. For 11 of the 12 criteria that were used to rate the two methodologies, the evaluators believed that HEMED was an improvement within the fixed-principle design environment. This research demonstrated that HEMED was an improvement over the previously documented early design-rating system within the aerospace manufacturing industry. With additional testing, the researchers strongly believe that HEMED can be successfully applied and demonstrated as an improved early design evaluation approach throughout the piece-part manufacturing industry.