Prediction and analysis of size tolerances achievable in peripheral end milling

Abstract

Size tolerance is the most critical parameter requiring attention for ensuring dimensional repeatability of manufactured component parts, yet very little research has been reported on this important topic. This paper presents a method for predicting size tolerances of component parts machined through peripheral end milling. The method makes use of prototype software based on previously reported cutting-force and surface-generation models in which the end mill is modelled as a cantilever beam rigidly gripped by the tool holder. It also takes into account the effect of size variation for the cutting tool. The method is validated through several cutting experiments. For further analysis, the method is employed for predicting the size tolerances of a prismatic component by varying one controllable variable at a time and then monitoring the relationship between size tolerance and the variable. When a distinct relationship is noted it is verified both analytically and experimentally. The results indicated that whilst the average size variation, which contributed to the variation of the basic size of component parts, is always proportional to the metal removal rate, the range of size variations that contributed to the size tolerance is not. Therefore, there is scope for increasing the metal removal rate without sacrificing the size tolerance. The knowledge acquired through this research can be applied for selecting an optimum cutting condition using the developed method when the size tolerances of component parts are specified.