Parameters Influencing Geometrical Quality and Station Cycle Time in Sheet Metal Assemblies

Paper in proceeding, 2009

In the automotive market, geometrical quality can often be just that competitive edge that attracts the customer. Station cycle time influences plant throughput and required plant investment costs. During product and process development, these two important characteristics are addressed by tolerance analysis and off-line programming. In the automotive industry, tolerance analysis and off-line programming are basically sequentially applied with only limited interaction. We argue that this partial separation can lead to suboptimal geometrical quality or station cycle time. Targeting the process layout design of a sheet metal assembly station, we argue that geometrical quality and station cycle time often are influenced by the same set of parameters. In addition, we argue that geometrical quality and station cycle time often are subject to trade-off, i.e. that a certain parameter change influences one characteristic favourably and the other unfavourably. For instance, fixture geometries that are effective in terms of geometrical quality, do often constitute bulky obstacles that have a significant negative influence on station cycle time. Furthermore, welding concepts that favor geometrical quality usually entail longer robotic travel and require lower robot operating speeds.