Product Family Formation for Reconfigurable Assembly Systems

Abstract

Appropriate formation of product families for Reconfigurable Manufacturing Systems (RMS) is of a great importance for a cost-effective and productive manufacturing. One key aspect that differentiates assembly systems from other manufacturing systems is that they often require parallel operations, which is not common for other types of manufacturing systems such as dedicated manufacturing systems. This paper introduces the first product family formation method that particularly addresses Reconfigurable Assembly Systems (RAS). Product assembly sequences are used, along with product demand and commonality, as similarity coefficients. Product assembly sequences are represented in the form of binary rooted trees and, based on well-established tree matching techniques used in Biology and Phylogenetics, a new sequence-based similarity coefficient is introduced to measure the distance between any given pair of assembly sequence trees. Hierarchical clustering is then applied to generate various groups of product families that may be formed based on each similarity coefficient. A novel consensus tree-based method is applied to find the best aggregation for the three different hierarchical clustering trees. The proposed method is applied to an example of eight products. Applying the proposed method to a Reconfigurable Assembly System should significantly improve system efficiency and productivity and hence supporting cost effective production.