UBC Theses and Dissertations
An investigation into tool-wear and phenomena influencing tool-life in milling Oyawoye, Orisunmbola A.
The subjects of tool-life, tool-wear and machinability have attracted extensive research interest most of which have been directed toward turning operations. The added complexity of milling operations, resulting from both the discontinuous nature of the process and the varying chip thickness during cut, are the reason for reduced research interest in comparison to turning. Although several researchers have examined the milling process, considerable controversy still surrounds the basic factors influencing tool-life in milling. In the study of the basic factors involved in the milling of both high strength steel and titanium alloy work materials, the basic form of the equations which result tend to support a thermal fatigue process as the most likely source of difference between continuous and discontinuous cutting. To validate this hypothesis further, special tests have been conducted within an inert atmosphere to ascertain the influence of oxidation on wear rate. It is also found that the influence of exit conditions may be critical in some circumstances, and experiments have again been carried out to examine this phenomenon. Finally, from a consideration of the tracking of tool-wear in milling operations, a comprehensive scheme which allows both identification of cutting conditions and tracking of wear on end mills and face mills is presented.
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