Process Planning and Due-date Assignment with ATC Dispatching where Earliness, Tardiness and Due-dates are Punished Halil Ibrahim Demir, Tarık Cakar, Mumtaz Ipek, Ozer Uygun, and Murat Sari Industrial Engineering Department, Sakarya University, Sakarya, Turkey Email: {hidemir, tcakar, ipek, ouygun, muratsari}@sakarya.edu.tr Abstract—Conventionally process planning, scheduling and due-date assignment are performed independently. But treating these three functions simultaneously improves global performance. In literature there are numerous works on process planning and scheduling and on scheduling with due-date assignment. But integrating these three functions are not treated much. In this study, process planning and due-date assignment are simultaneously treated with ATC dispatching using genetic algorithm (genetic search) and random search. Three shop floors are tested in this study. One is small shop floor with 50 jobs and the other is medium shop floor with 100 jobs and the third one is the largest shop floor with 200 jobs. In this study Earliness and Tardiness symmetrically and quadratically penalized and length of due-date is linearly punished. Results of Genetic search and Random search are compared with each other and with random solution and with unintegrated solution. Results are summarized and compared with each other. According to results Genetic search-integrated solution is the best, Random search-integrated solution is the second, Random-integrated solution is the third and Unintegrated- random solution is the poorest. 1 Index Terms—Due-date assignment, Process planning, Job shop scheduling, Genetic Algorithm I. INTRODUCTION When we look at the literature we can see many works on integrated process planning and scheduling and numerous work on scheduling with due-date assignment. Traditionally these three functions were being done sequentially and separately. Unintegrated solutions become poor inputs to the downstream functions and global performance can be poor. For example if process plans are made independently then process planner can choose same desired machines repeatedly and they don’t care about scheduling and due-date assignment performance. Because they can select same machines repeatedly some machines can become bottleneck and some machines can be starving and this cause unbalanced machine loading. When some unexpected things occur such as machine breakdowns then it becomes hard to react these occurrences. If we integrate process plans with other functions then in case of need Manuscript received July 1, 2014; revised November 1, 2014. we can react to the unexpected situation and we can improve shop floor balance. Good and flexible inputs for scheduling and due-date assignment provide us to make better scheduling and better due-date assignment. The scheduling problems involving due dates are of permanent interest. In a traditional production environment, a job is expected to be completed before its due date. In a just-in-time environment, a job is expected to be completed exactly at its due date…The problems with due-date determination have received considerable attention in the last 15 years due to the introduction of new methods of inventory management such as just-in- time (JIT) concepts. In JIT systems jobs are to be completed neither too early nor too late which leads to the scheduling problems with both earliness and tardiness costs and assigning due dates. T.C.E. Cheng, who contributed a lot to the due date assignment and the related scheduling approaches, remarks that “completing a job early means to bear the costs of holding unnecessary inventories, while finishing a job late results in contractual penalty and loss of customer good-will” Gordon et al. [1]. II. LITERATURE SURVEY For integrated process planning and scheduling problem, Tan and Khosnevis [2] presented a good literature survey. For scheduling with common due-date assignment problem, it will be useful to see Gordon et al. [1] as a state-of-the-art survey about this topic. Following study uses multiple process plans in contrast to traditional way. Chen and Khoshnevis [3] investigated the problem of integrating the process planning and scheduling functions as a scheduling problem with flexible process plans. They developed a concurrent assignment algorithm based on the added flexibilities introduced by the integration Above study used multiple process plans and following study, Jiang and Chen [4], investigated the influence of alternate process planning on the scheduling performance according to three criteria, which are mean tardiness, mean work-in-process and mean machine utilization. Integration can be done with manual process plans or computer aided process plans. Computer advantage is very important to develop alternative process plans and 2015 Engineering and Technology Publishing 197 doi: 10.12720/jiii.3.3.197-204 Journal of Industrial and Intelligent Information Vol. 3, No. 3, September 2015