Simulation-based potential analysis of line-less assembly systems in the automotive industry

Increasing product variety, shorter product life cycles, and the ongoing transition towards electro-mobility demand higher flexibility in automotive production. Especially in the final assembly, where most variant-dependent processes are happening, the currently predominant concept of flowing line assembly is already been pushed to its flexibility limits. Line-less assembly systems break up the rigid line structures by enabling higher routing and operational flexibility using individual product routes that are takt-time independent. Hybrid approaches consider the combination of line and matrix-structured systems to increase flexibility while maintaining existing structures. Such system changes require a high planning effort and investment costs. For a risk-minimized potential evaluation, discrete-event simulation is a promising tool. However, the challenge is to model the existing line assembly concept and line-less assembly for comparison. In this work, a comprehensive scenario analysis based on real assembly system data is conducted to evaluate the potential of line-less assembly in the automotive industry. Within the simulation, an online scheduling algorithm for adaptive routing and sequencing is used. Based on an automated experiment design, several system parameters are varied full-factorially and applied to different system configurations. Various scenarios considering worker capabilities, station failures, material availability, and product variants are simulated in a discrete-event simulation considering realistic assumptions. Results show that the throughput and utilization can be increased in the hybrid and line-less systems when assuming that the stations will have failures and the assumption of an unchanged order input.