Scheduling Customized Orders: A Case Study at BEST Transformers Company

Abstract

-Stochastic operation times make job-shop scheduling harder at companies which work based on project type laborintensive production in a dynamic environment. The operation times are not known before production and change based on the orders' technical specifications. In performing required operations with the aim of producing a final product, scheduling is required for different purposes such as minimizing makespan, maximizing resource utilization, etc. This is important as it enables companies to meet customer demands by due date and reduce the labor cost on the finalized product. In this study, an order scheduling algorithm is proposed for nearly optimizing average makespan for several waiting orders in a transformer company's core production workshop considering dynamical production environment. The proposed algorithm adopts the technical order specifications, computes the stochastic operation times making use of simulation, and schedule orders using one of the widely used meta-heuristics, namely genetic algorithm. The objective is to determine the entry sequence of the waiting orders to the core production workshop for minimizing their average makespan which directly influences the resource utilization, efficiency, and labor costs.

Scheduling Customized Orders by Considering the Ergonomic Constraints: A Case Study at YEMTAR Company

“…In this study GA is used to find the best sequence of customer orders, which minimizes average makespan, and Arena simulation is used to calculate processing times and makespan of operations based on order sequences generated by GA. Please refer to [1,3,18,19] for a detailed discussion on the problem and also refer to [20,21] for a detailed discussion on GA.…”

“…Simulation is "the imitation of the operation of a real world process or system over time" and enables the study of and experimentation with the internal interactions of a complex system [1,22]. In a simulation work, numerical experiments are conducted on digital computer and it can be used a general-purposed programming language or a special-purposed simulation programming language.…”

“…Arena exploits ActiveX Automation and Visual Basic for Applications (VBA) for integrating directly with other programs such as Microsoft Office. In this paper, Arena 14 simulation software is used for the simulation [1,3]. The proposed GA is coded in VBA environment which makes connection to Arena simulation software hassle-free.…”

“…In the labor intensive project type manufacturing; except a few similar orders produced frequently; there are unlimited types of different orders varying based on the technical specifications demanded by the customers and the state of the shop floor is changed continuously. This variation causes unknown processing times for each type of order which makes order scheduling harder [1][2][3][4][5].…”

“…In such a production system, each of the received order can be considered as a new product. The orders may be completely different because of their technical specifications demanded by the customer [1,3].…”