A Reliability Based Maintenance Policy of the Assembly System Considering the Dependence of Fixtures Elements Across the Stations

In the mass production assembly process, the fixture system’s reliability is vital for products’ quality. The failure of the fixture system depends not only on the assembly operation times, but also upon the system degradation which is caused by the original manufacturing accuracy of fixtures, assembly forces, qualities of subassemblies from upstream assembly stations etc. In this paper, we propose a dynamic preventive maintenance policy for the fixture components based on the system reliability model of a multi-station assembly process. The proposed reliability model not only considers the degrading fixture components and other factors in the station, but also the dependence of process factors across the stations. Based on the reliability model and a given cost, an optimization method for the manufacturing tolerances and a dynamic maintenance schedule of locating pins are presented. At last, a body side assembly case is given to illustrate the proposed method.