2019 年 85 巻 10 号 p. 856-865
Machining process is a typical example of the non-equilibrium phenomenon. The aim of this study is to investigate the influence of built-up layer (BUL) on the tool wear mechanisms of uncoated and coated carbide tools. To investigate how the BUL formation affects the tool wear mechanisms, dry cuttings of Inconel 718 with uncoated, PVD and CVD coated carbide tools were conducted. The worn cutting tools were analyzed using laser scanning microscopy, scanning electron microscopy and electron probe micro analyzer. It is found that BUL can for m on the tool rake face under different cutting conditions. At the beginning of cutting, the coating of coated carbide tool falls off quickly, then BUL forms on the tool rake face which can protect the tool from further wear. Concerning the flank wear, it is confirmed that the size of BUL has a great influence on the flank wear. In addition, the adhered material on the worn flank face, which is called as flank built-up (FBU), is also an important factor for the flank wear development. And the effects of the BUL/FBU formation should be considered into the cutting tool's flank wear model. To further understanding the experimental results, the thermodynamic discussion is conducted. The result shows that BUL/FBU can be considered as a form of “dissipative structure substance” which can reduce tool wear during cutting and tool wear formation is an irreversible energy dissipation process relating to entropy production.
