Optimization of the Cab Production Sequence : A simulation-based study at Volvo Group Trucks' cab plant in Umeå

Abstract: Volvo Group’s cab plant in Umeå produces cab bodies and consists of three operating areas; the Stamping and parts production, the Body in White and the Paint shop. Today the plant produces around XXX cabs/week, but the goal is to reach the invested capacity of XXX cabs/week. In order to increase the production capacity, the efficiency of both the manual and the automated processes need to be improved. Unlike the manual processes in where the capacity can be increased by enlarged workforce, the automated processes need to be optimized. Today the cabs are produced in the same order as the orders are received. The cab plant wants to investigate if the capacity of the automated segment in the Body in White unit can be increased by changing the order in the production sequence. This culminates in the following problem definition:  Is there untapped potential of the Body in White that can be achieved by an optimization of the production sequence? If so, how can Volvo Group’s cab plant in Umeå utilize this knowledge in the production planning process? The objective of the project was achieved by combining discrete event simulation with a heuristic optimization approach. The results shows that long batches in the production sequence limit the throughput of the system. By spreading the unfavorable subsequences of batches evenly over the production sequence, the total throughput of the Body in White can be increased by 52 cabs/week.