Design for Automatic Assembly: A new Approach to Classify Limp Components

Part design is the most important enabler to automate assembly processes. Design work done in companies' development departments determines most of the product and production costs through material selection and number of components. Part design mostly focuses on functionality but there is still high potential in production processes. To optimize part design for manufacturing and assembly processes first approaches were made between 1960 and 1980. Nowadays, these systematic procedures for optimized component development with respect to production processes are known as 'Design for Manufacturing and Assembly' and 'Design for Automatic Assembly'. Existing part design rules mainly focus on rigid parts. Limp components are avoided in automatic assembly processes, due to limp material characteristics such as strong deformations due to external force or momentum and shape change during manipulation. However, many products, for example automotive wire harnesses, consist of a considerable amount of limp components. A better design for limp components and their joining-partners might be a solution to simplify subsequent automated production processes. The first step therefore is limp component classification. This paper introduces a new scheme of limp component classification oriented towards an abstraction of automated assembly processes. Different limp material characteristics influence several stages of this process. Therefore, relevant limp material characteristics are assigned to the affecting stages. With this classification, the specific challenges in the automated assembly process become clear. This serves as a basis to define challenges for future automated assembly. In addition, the definition of general design rules for limp components concerning automatic assembly becomes feasible. This paper highlights challenges in limp part assembly automation, abstracts automated assembly processes, reviews and discusses first approaches in limp part classification, and introduces a new scheme for limp component classification. The paper concludes with necessary future research based on the proposed limp component classification.