Optimizing the makespan of washing operations of medical devices in hospital sterilization services

In this paper, we deal with the problem of minimizing the makespan of washing operations in hospitals sterilization services. After use in operating blocs, reusable medical devices (RMD) are sent to the sterilization service which is composed of various processes. In the washing step, different sets of RMD, used for different operations, may be washed together without exceeding washer capacity. An RMD set must be washed in one cycle and so, we are not allowed to split RMD sets. In this case, we consider a batch scheduling problem where RMD sets may have different sizes and different release dates for washing. Note that if all release dates are equal, the problem is reduced to a bin packing problem. We provide a mixed integer linear programming model which aims at minimizing the makespan of washing operations. We provide and also experiment some heuristics based on classical bin packing algorithms.