A method for assembly line balancing with more than one worker in each station

TLDR

Typical assembly lines are serial, so the cycle time is limited by the longest work element, which caps production rate. This paper introduces the Parallel Assignment Method (PAM) to raise production rates by assigning multiple workers to a single station. PAM first assigns work elements to stations within multi‑stage upper time limits, then distributes elements among workers at each station so each worker handles shorter, indivisible tasks, offsetting the longer operation time per worker. PAM successfully solves practical problems that serial line‑balancing methods cannot, demonstrating its effectiveness.

Abstract

The typical assembly line is serial with no paralleling of work elements and work stations allowed. The series assumption restricts the least cycle time to be the maximum work element time, thus limiting the production rate. An alternative way to increase the production rate (hence lowering the cycle time) is by assigning multiple workers to one work station. In this paper we propose the parallel assignment method (PAM) for achieving a higher production rate. In the first phase of PAM the work elements are assigned to work stations under the multi-stage upper time limits. But as two or more workers are assigned to one station, the operation time of each worker is longer in proportion to the number of workers at the station. Therefore, in the second phase of PAM work elements are assigned to the workers in each station so that each of the workers may perform shorter work elements where the work element is a minimum rational indivisible work item. Practical problems which cannot he solved by serial line balancing methods are provided and.solved to explain the effectiveness of PAM.