ABSTRACT

Typically, general job shop scheduling problems assume that working times of machines are equal, for instance eight hours a day. However, in real factories, these working times are different because the machines may have different processing speeds, or they may require maintenance. That is, one machine may need to be operated only half day whereas other machines may have to be operated for the entire day. So, each machine has its own working time window. In this paper, this type of problem is referred to as a job shop scheduling problem based on machine availability constraint which is more complex than typical job shop scheduling problems. In the previous research, this type of problem has been rarely investigated before. Thus a new algorithm is developed based on a non-delay scheduling heuristic by adding machine availability constraint to solve job shop scheduling problem with minimize makespan objective. The newly developed algorithm with the machine availability constraint assumption is more realistic. The study reveals the result of algorithm that consider machine availability constraint is better than the result of algorithm that ignores machine availability constraint when apply to the real problem.