Modeling manufacturing quality constraints for product development

When bringing a new or improved product to market, a design and manufacturing enterprise can speed the process and improve the result by understanding and designing within the manufacturing process used. We propose process characterization modeling and experiments aimed at uncovering their effect upon product functional requirement metrics. In a real industrial design and manufacturing enterprise, however, social and managerial problems drive any such design-for-manufacturing integration modeling. Modeling and experiments are limited to activities that provide direct answers to short-term real identified problems. This means that only a continuous improvement approach is practical to construct process constraint models. We develop and demonstrate a methodology to quantify the quality constraints imposed on a product design by its manufacturing process. We start with the sequence of operations transforming the incoming material into the final product, which is diagrammed into a topology of the operational sequence. Next, performance metrics are identified which correspond to the customer requirements. Using engineering analysis, a basic model is developed relating known product and material variables to the metric. Production data, either from designed experiments or from natural variation occurring during production, are measured to validate the basic model. Next, each operation in the process topology is analyzed for potential effect upon the model. Modes of impact of each operation upon the metric are conceived, and quantified into the basic model. These modes become either supported or not by the production data. The methodology, therefore, is one of continuously improving the understanding of the process imposed constraints to improve the product. We demonstrate the methodology with a running example, characterizing the process imposed constraints upon a low temperature cc-fired ceramic circuit assembly.