Absenteeism/turnover analysis in mixed-model assembly lines

Mixed model line produces several product models, and requires from a substitute worker more learning than single-model lines. Assembly lines typically employ hundreds of workers and absenteeism and turnover are encountered daily. Absenteeism and turnover in any station along the line require replacing the absent worker by a new one with a learning curve. The new replacement worker has slower learning process due to the less repetitive work. Still, the learning pattern and effectiveness of the substitute worker depends on the similarity of product models launched. This research analyzes the impact of absenteeism and turnover in assembly lines of mixed model. It shows that model sequencing policy has very significant effect on the line's throughput as it affects bottleneck stations. A simple example is used to show that substitute workers generate smaller throughput on mixed model lines than on a single model line.