Best design granularity to balance assembly complexity and product modularity

This paper presents a new methodology for designing modular products taking into account assembly complexity and Design for Assembly. DFA encourages components integration to reduce assembly time, while modularity promotes partitioning and decomposition of product architectures into components and modules to facilitate interchangeability. A product granularity level determines the details of its architecture. The best product architecture granularity level, and size and number of product modules are determined using Cladistics - a hierarchical classification tool - along with the Design Structure Matrix (DSM) and assembly insertion and handling complexity indices. A case study using a DC vibration motor is used to demonstrate the application of the presented methodology. It is observed that increasing assembly complexity promotes coarser product architecture granularity and more modularity results in finer product granularity. Use of the presented design methodology achieves the best trade-off between products modularity and integration.