Product complexity and design of inspection strategies for assembly manufacturing processes

TLDR

Assembly processes strongly influence product quality and cost, with operator errors contributing significantly to defects, and models have linked assembly complexity to defect rates. The paper proposes a new paradigm for designing inspection strategies tailored to short‑run production where conventional methods are impractical. The authors develop defect‑generation models to predict defect probabilities and use them to design inspection procedures, demonstrated on a case study of assembling mechanical components for hardness‑testing machines.

Abstract

In the manufacturing field, the assembly process heavily affects product final quality and cost. Specific studies, concerning the causes of the assembly defects, showed that operator errors account for high percentage of the total defects. Also, models linking the assembly complexity with the operator-induced defect rate were developed. Basing on these models, the present paper proposes a new paradigm for designing inspection strategies in case of short-run productions, for which traditional approaches may not be carried out. Specifically, defect generation models are developed to get a priori predictions of the probability of occurrence of defects, which are useful for designing effective inspection procedures. The proposed methodology is applied to a case study concerning the assembly of mechanical components in the manufacturing of hardness testing machines.