Optimal production sequencing problem to minimise line stoppage time in a mixed-model assembly line

Abstract

Mixed-model assembly line is utilised to assemble many product variants on a single line in automobile and other industries. In just-in-time production system, the automation (Jidoka) allows workers to stop a conveyor line whenever they fail to complete their assembly operations within predetermined process times. Given this situation, it becomes important to determine the production sequence to minimise the total conveyor stoppage time in the mixed-model assembly line. In this article, we propose an explicit and complete formulation of the production sequencing problem for the mixed-model line, in which the objective function is to minimise the total line stoppage time. Some important properties are derived and by relaxing the integer constraints in the formulation, a branch and bound algorithm is developed. The performance of a commercial mathematical programming package is discussed by solving several numerical examples using the formulation.

Keywords:

• mixed-model assembly line
• production sequencing
• line stoppage
• branch and bound algorithm