PT. Central Texindo is a textile company engaged in the dyeing and refinement of textile materials with the aim of processing gray fabrics from other companies into fabrics. The production system applied by PT. Central Texindo is Make to Order (MTO) which means making products according to consumer demand. The company had eight types of machines to support the production process with different quantities of each type. All machines have the same capabilities and capacity, which they have the same function and can produce up to 10 rolls/day or around 25kg of fabrics, the differentiation is only on the specification of the machine. In fulfilling customer demand, PT. Central Texindo makes scheduling based on orders from customers. All products have their own production targets every day to fulfill this requirement. However, based on the production report that has been summarized in November 2021 – March 2022, there are ordered products that are not fulfilled in the specified time target because of tardiness occurs. The company initially used the First Come First Serve (FCFS) scheduling system. However, the current scheduling system done randomly and generates a scheduling sequence that performs relatively poorly in terms of tardiness. From November 2021 – March 2022, there are 34 jobs that are operated. And out of 34 jobs, the number of tardy jobs is 12 with total tardiness is 1448 hours. To solve the tardiness problem, this final project proposed scheduling algorithms which is Branch and Bound by using LINGO software. The result based on Branch and Bound method by using the LINGO software shows global optimum solution with five jobs that experienced tardiness and the value of tardiness is 688 hours. The result is better compared to the existing conditions, where the initial conditions show a tardy job of 12 jobs with total tardiness of 1448 hours. The results obtained not only show a reduction in total tardy jobs and total tardiness, but also show machine job sequences. Based on the design results, Branch and Bound are able to minimize total tardiness up to 54%.
Keywords — Scheduling, Identical Parallel, Knitting Department, Tardiness, Branch and Bound