Assessing performance of Workload Control in High Variety Low Volumes MTO job shops: A simulative analysis

This paper deals with Workload Control (WLC), one of the best techniques to control Work In Process (WIP) and to stabilize Lead Time (LT) in job-shop systems. Our focus is on the job release strategy and, specifically, on the selection and dimensioning of suitable norms; a challenging problem, which is often the cause of the little industrial use of WLC. Specifically, our aim is to assess whether or not the use of easy to implement norms, appealing also from an operating point of view, may be enough to boost performance of a productive system. To this aim, a thorough discrete events simulation was made, considering a realistic job-shop environment in different operating conditions. Job release was subjected by WLC, regulated by two consolidated norms (i.e., Shop-Load and Bottleneck-Load) and by a novel one, which leverages on the grouping of jobs into families. Obtained outcomes are highly satisfactory, since good performances, in terms of WIP minimization and Due Dates compliance can be obtained, especially in highly constrained productive environments.