Development of a heuristic algorithm for finding optimum machine loading sequence in fabrication shop with job shop layout

摘要

Sequencing and scheduling techniques are the means for taking decisions about the order and time in which a set of jobs are to be processed through a set of machine(s) to get the output of finished products in a desired order and time. Among all the industries where the scheduling problem exists, Job Shop Scheduling (JSS) problem is considered to be the most difficult and complicated one to be solved and as such it is considered to be a Nondeterministic Polynomial time - hard (NP-hard) category problem. Hence, the number of techniques developed so far is not enough to compute the optimum results. Looking at this aspect, the present work is an attempt to solve JSS problem by developing a heuristic algorithm. The data are collected from the fabrication shop of a sheet metal processing industry with Job Shop (JS) layout. It is found that the algorithm is useful in minimizing the values of makespan and machine idle time along with reduced number of new machine setups required. To test its validity, the collected data are also analysed by using some standard dispatching rules and when the results are compared, it is found that the developed algorithm is producing better results. Moreover, by following the obtained sequence, it is seen that the inter-departmental co-ordination is established and internal customer satisfaction is attained in respect of components' availability at the time of their requirement.