MATHEMATICAL MODELLING OF FMS FOR LOADING: AND SCHEDULING

Abstract

Loading and scheduling of manufacturing system have become a- c l iche` of research in the area. ea. of Production and Industrial Engg. But still no loading and scheduling model which is easy to implement at shopf l oor without sacrificing details and optimality is available in literature. Most of mathematical modelling - is either too complicated to be implemented or it is away from the real situations prevailing at the shop floor. Loading and scheduteing gffects and get effected by several factors. From the productivity point of view loading- and scheduling should be such that it helps in getting out-put at the minimum possible cost. In this thesis work two separate models are developed. Loading Model is fo-r a multiple routs FMS and sched-uIing model is for a single route FMS problem with multiple criteria. . Utilization of machines get affected by loading decisions. A uniform loading of all the machines help in maximizing utilization. Model recommended here suggests a loading strategy with the help of multiple-cut-off. Model is tested with one example, out come gives a loading plan where average deviation for routes is approximately '%. The costs for scheduling are related with make span of jobs, machine idle time and tardiness of job. Aim of scheduling is to select a schedule based on least penalty related to three principal cost. It is very difficult to get an optimum solution of multicriteria problem by conventional mathematical tools. Upto now classical flowshop problem was considered either for single criteria or bicriteria with complex operation research techniques. In this work the three principal costs_ are considered simultaneously with simple concept of penalty. Scheduling is tested with three examples.One example is taken from Katsundo Hitomi's paper. The result of our model is better as compare to Hitomi's model (Petrov's method) even for single criteria and,the result of multicriteria is excellent. (