A new look at the bowl phenomenon

TL;DR

This paper investigates the bowl phenomenon in assembly lines with heterogeneous workers, confirming that slightly unbalanced lines with central stations less loaded can achieve higher throughput, especially with workers with disabilities.

Contribution

It extends the understanding of the bowl phenomenon by analyzing its presence in assembly lines with heterogeneous workers, including those with disabilities, using modified models and simulation.

Findings

Bowl phenomenon confirmed in lines with heterogeneous workers

Unbalanced lines can outperform balanced ones in throughput

Results deepen understanding of empirical assembly line behaviors

Abstract

An interesting empirical result in the assembly line literature states that slightly unbalanced assembly lines (in the format of a bowl - with central stations less loaded than the external ones) present higher throughputs than perfectly balanced ones. This effect is known as the bowl phenomenon. In this study, we analyze the presence of this phenomenon in assembly lines with heterogeneous workers (most of them, workers with disabilities). For this purpose, we modify an existing model for the assembly line worker assignment and balancing problem in order to generate configurations exhibiting the desired format. These configurations are implemented in a stochastic simulation model and the obtained results are analyzed. The findings obtained here confirm the existence of the bowl phenomenon in such situations and contributes to deepen our knowledge in this empirical phenomenon.