Integrated process planning, WSPT scheduling and WSLK due-date assignment using genetic algorithms and evolutionary strategies

Abstract

Process planning, scheduling and due-date assignment are three importantmanufacturing functions in our life. They all try to get local optima and there canbe an enormous loss in overall performance value if they are handled separately.That is why they should be handled concurrently. Although integrated processplanning and scheduling with due date assignment problem is not addressed muchin the literature, there are numerous works on integrated process planning andscheduling and many works on scheduling with due date assignment. Most of theworks in the literature assign common due date for the jobs waiting and due datesare determined without taking into account of the weights of the customers. Hereprocess planning function is integrated with weighted shortest processing times(WSPT) scheduling and weighted slack (WSLK) due date assignment. In thisstudy unique due dates are given to each customer and important customers getcloser due dates. Integration of these three functions is tested for different levelsof integration with genetic algorithms, evolutionary strategies, hybrid geneticalgorithms, hybrid evolutionary strategies and random search techniques. Bestcombinations are found as full integration with genetic search and hybrid geneticsearch. Integration of these three functions provided substantial improvements inglobal performance.