Optimizing manufacturing by selecting tolerances and capacity for precision of machine tools

摘要

A sequence of machining operations generates several surfaces to the dimensions required. Manufacturing cost is highly sensitive to manufacturing tolerance specification and to the machine tool selected to perform a given set of operations. Indeed, the hourly cost of machining increases when closer dimensional tolerances are imposed. It is therefore expedient to select machines having a "capability index" deemed optimal as regards satisfying the necessary precision. Our study aims to develop a procedure whereby the part manufacturing process can be optimized with respect to cost by means of: a) A unidirectional analysis of the average difference between functional (required) tolerances and the manufacturing (achievable inherently by selected machine tools) tolerances for the sequence of machining operations allows the selection of the process sequence with the minimum difference and b) Choosing among available machine tools suited to the process but taking into account their hourly cost and their capacity for precision.