Improving Shoes Production Flow in a SME Using a Theory of Constraints (TOC) Approach

Abstract

Abstract. ‘Rumah Sepatu’ is a small and medium-sized enterprise (SME) located in Bandung, Indonesia. It is operating in the footwear manufacturing industry under a make-to-order (MTO) market response strategy. The production system consists of several workstations, namely Pattern Marking, Upper Assembly, Initial Quality Control, Upper Lasting, Outsole Oven Processing, Outsole Cooling, and the Assembly of the Upper and Outsole. Each workstation performs different operations with varying processing times. Significant differences in processing time among these workstations lead to workload imbalance along the production line. This imbalance causes the accumulation of work in process (WIP) and results in the emergence of bottlenecks, which hinder the smooth flow of production and prevent the fulfillment of customer demand. This study aims to identify and manage the bottleneck in the production flow using the Theory of Constraints (TOC) approach. The research methodology includes bottleneck identification, production quantity optimization using Linear Programming, the implementation of Drum-Buffer-Rope (DBR) scheduling, and improvement actions focused on the bottleneck workstation. The results indicate that the Upper Assembly workstation is the primary bottleneck, with a workload level of 181.78%. Under the existing production conditions, the system is unable to fully satisfy customer demand. The proposed improvement, implemented by adding one permanent operator at the Upper Assembly workstation, increases production capacity from 645 units to 1,171 units per month. As a result, system throughput rises from IDR30,044,100 to IDR68,591,700, representing an increase of 128.28%.