Abstract
In automated machining systems, interruption in machining due to the sudden fracture of a cutting tool is detrimental for constructing fully automated machining systems. Not only does it affect the quality of the machined surface, but it also halts production. It is well known that tool-life is probabilistic in nature and shows considerable variations. A statistical approach based on tool-life distribution is well recognized for designing effect and economical automated machining systems. Production halt by sudden fracture of cutting tool results in the loss of available time and materials, and the increase of production cost. This paper presents statistical models to analyze the production costs for fully automated unmanned machining systems as well as for semi-automated manned systems. A new criterion based on production cost is proposed for shifting to the fully automated machining system from the semi-automated manned system. The shortage of machined products caused by the interruption in the fully automated unmanned system is supposed to be supplied by the stocked machined products. Supply costs of the shortage are formulated in production cost. A statistical decision procedure for shifting to the fully automated unmanned machining system from the semi-automated manned system is given.
