Planning and scheduling in an FMS

The Dutch institute of applied physics of TNO and the Institute of Metals TNO (Apeldoorn) have installed a flexible manufacturing system (FMS). The main components of this FMS are a turret lathe, a machining centre and a transport system. One of the objectives of this system is to produce a wide variety of parts in small batches. Several interesting (short term) planning and scheduling problems arise from this objective. Among others, (1) which orders should be processed in a certain period, and (2) in what sequence should the selected orders be processed. In solving these problems, one has to take into account due dates, process plans (routing), capacities of the machines and the tool magazines, tool and jaw changing times, limited fixturing capacity, fixturing and clamping times and the limited number of operators and transport devices. The paper describes the typical characteristics of the FMS with respect to the planning and scheduling problems. A way to solve these problems is presented.