Mapping workers' performance to analyse workers heterogeneity under different workflow policies

Manual work in assembly lines allows one to benefit from human reasoning capabilities and to assure the flexibility to adapt to fluctuations in production volume, products mix and reduced product lifecycles. With the objective of quantifying and systematizing the knowledge about the heterogeneity of workers' performance, data was collected in an industrial setting. The results demonstrate a significant variation in workers' performance in terms of speed and variability of the task completiontime. A mapping approach is proposed aiming to quantify the workers' performance and visualize performance patterns. Since the human performance is influenced by the setting where the workers perform their job, two real assembly line pacing mechanisms were set and studied: pacing derived from the manual assembly system rhythm and pacing imposed by a fixed time constraint. The type of pacing clearly influences workers' performance (i.e., speed and variability) and revealed a significant influence in the assembly line output. In particular, imposing a fixed and equal time constraint for every worker reduces the heterogeneity of workers' performance and improves the assembly line output. (C) 2015 The Society of Manufacturing Engineers. Published by Elsevier Ltd. All rights reserved.