Balancing earliness and tardiness within workload control order release: an assessment by simulation

Abstract

Most Workload Control literature assumes that delivery performance is determined by tardiness related performance measures only. While this may be true for companies that directly deliver to end-customers, for make-to-stock companies or firms that are part of supply chains, producing early often means large inventories in the finished goods warehouse or penalties incurred by companies downstream in the supply chain. Some earlier Workload Control studies used a so-called time limit, which constrains the set of jobs that can be considered for order release, to reduce earliness. However, recent literature largely abandoned the time limit since it negatively impacts tardiness performance. This study revisits the time limit, assessing the use of different adaptive policies that restrict its use to periods of either low or high load. By using a simulation model of a pure job shop, the study shows that an adaptive policy allows to balance the contradictory objectives of delaying the release of orders to reduce earliness and to release orders early to respond to periods of high load as quick as possible. Meanwhile, only using a time limit in periods of high load was found to be the best policy.

Investigation of Workload Control Methods for Shops with Re-Entrant Flows

“…ORRs such as immediate release (IMMD) and continuous release policies yield better outcomes when reentrant flows are considered, however, LUMS COR and Lancaster University Management School order release (LUMS) showed detrimental effects with re-entrant flows Thürer & Stevenson [22]. Recently, Haeussler et al, [29] investigated the use of time limits in high and low load periods. A mechanism that works on dynamic time limits to balance the job release to respond to high or low load periods either spontaneously or by delaying the response.…”