Machine Loading

In an FMS, Operation management is more intricate than that of the conventional manufacturing systems, that means transfer line or job shop production system and based largely upon how the decision problems is being tackled. It is primarily because of versatile machines, which are capable of performing a broad range of manufacturing operations with quick tooling & instruction changeovers that result in various alternative routes for processing of part types. In most of the FMSs, the part to be machined ought to be loaded on a pallet of some type and after required operations; it is required to be taken-off from the pallets. In other terms, we might say that loading involves taking a component delivered to the systems & preparing it for processing. After processing, the component is brought back from its pallet to the load/unload area and this is placed on the floor to wait its disposal to assembly department or a storehouse. These actions come under unloading process.

Machine loading problem of a flexible manufacturing system is known for its difficulty, which encompasses several types of flexibility aspects pertaining to part selection and operation assignments with constraints ranging from simple algebraic to potentially complex & conditional one. Decision pertaining to machine loading difficulty has been considered as tactical level planning decision that behaves as a tie between strategic and operating level decision in manufacturing. This receives the input from preceding decision levels, such like part mixes selection, aggregate planning, resource grouping, etc. and transfer it to the succeeding decision levels of resources scheduling and dynamic operation planning and control. It is why the FMS loading problems have been rigorously pursued in the recent past.

In fact, Stecke (1983) studied machine loading difficulty in detail and described six major objectives :

• Balancing the workload per machine for a system of groups of pooled machines of equal sizes;
• Minimizing the number of movement;           
• Balancing the machine processing time;
• Maximizing the sum of operations priorities.
• Unbalancing the workload per machine for a system of groups of pooled machines of unequal sizes;
• Filling  up the tool magazines as densely as possible;