APPROXIMATE QUEUEING NETWORK MODELS FOR CLOSED FABRICATION/ASSEMBLY SYSTEMS. PART I: SINGLE LEVEL SYSTEMS.

The article presents information on the approximate queueing network models for closed fabrication/assembly systems. part I: single level systems. Discrete parts manufacturing systems, in which products are processed as discrete entities, are typical in the automotive, aerospace, and other metalworking industries, as well as in electrical and electronic industries. The operations involved in these manufacturing systems can be broadly classified in two categories: fabrication and assembly. Fabrication is traditionally characterized by metalworking operations- turning, drilling, milling, bending, shearing, and extrusion. Assembly, on the other hand, is defined as the fitting together of fabricated parts into subassemblies, assemblies, or the final product. It is typically characterized by joining processes such as welding and brazing and fastening processes involving screws, bolts, glue, and other fasteners, input stations. The service rate of the assembly station was fixed, and the service rates and the number of kanbans at the input stations were chosen to obtain a "balanced" system (the assembly station is equally likely to be paced by either of the input stations). The largest relative error in the throughput estimates is about 7.5%. The largest relative error is about 16%, for a station whose utilization is over 96%.