Effect of lot-size reduction and continuous improvement programmes on work in process and utilisation: a study for single-machine and flow-shop environments.

This article examines how six continuous improvement programmes (arrival variability, process variability, defect rate, time to failure, repair time, and set-up time), together with lot-size reduction, affect work in process (WIP) and utilisation in two different manufacturing environments: single-machine and flow-shop. The main tool we use to attain this goal is a combined system dynamics/factory physics approach proposed by Godinho Filho and Uzsoy [2011. The effect of shop floor continuous improvement programs on the lot size – cycle time relationship in a multi-product single-machine environment. The International Journal of Advanced Manufacturing Technology, 52, 669–681]. Results that emerged include (i) improvement in mean set-up time and variability (process and arrival for the flow-shop environment) has the largest effect on WIP reduction for the majority of scenarios evaluated in this article; (ii) improvement in arrival variability and small simultaneous improvements in all variables help to stabilise the amount of WIP downstream in the flow-shop environment even when large lot sizes are used; (iii) only a lot-size reduction combined with a set-up improvement programme, or small, simultaneous improvements in all variables, presents relevant effects to reduce workstation utilisation. [ABSTRACT FROM PUBLISHER]