DFQM - an approach for improving the quality of assembled products

In this paper we introduce first the concept of quality manufacturability (QM), and second a new methodology that focuses exclusively on evaluating a design from a quality perspective. We label this new approach as Design for Quality Manufacturability (or DFQM). The QM of a design is defined as the likelihood that defects will occur during its manufacture. Some designs are more likely than others to have a lower production yield late. The reason for this is that in any production facility there is an inherent defect occurrence process. This relationship between the defect occurrence process and the design is the basis for QM. DFQM enables product designers to evaluate and improve the QM of a design before prototype production. The key elements of DFQM are classes of defects, specific defects, influencing factors, factor variables, and error catalyst. A standard nomenclature for describing the specific defects and measuring the associated influencing factors is presented. The output of the DFQM method is the QM-Index matrix, which indicates the quality manufacturability of each part in the assembly, in terms of each class of defects. The concept of error catalysts and the derivation of the QM-Index matrix are presented. An illustrative example is included. The DFQM method is presently limited to assembly processes.