A production scheduling problem considering random failure and imperfect preventive maintenance

摘要

Many manufacturing companies are suffering from increasing machine wear with usage and age as degradation process. For a company to be successful, machines need to work continuously and make more profit in a certain period. However, machines can be unavailable due to the scheduled maintenance and unexpected failures. Hence, this study connects production scheduling with maintenance planning for a repairable system. Three types of maintenance are performed to restore the machines: (1) minimal repair is undertaken upon failure and the machine restored as bad as old; (2) replacement as a kind of perfect maintenance is implemented based on a cost-time rate function, which is defined to evaluate the economy of preventive maintenance action; and (3) preventive maintenance just makes the machine less deteriorated but not as good as new. Age reduction factor and failure rate increase factor are introduced to illustrate the imperfect character. The objective of this study is to maximize the total profit that is composed of production value, production cost, maintenance cost (including the preventive maintenance cost, replacement cost, and minimal repair cost for random failure), and lateness cost (which is contributed by the job sequence and maintenance activities). Finally, the proposed model is validated by a numerical example.