The Effects of the Carbide Grades on Tool Failure in Endmilling

Tool failure mechanism of carbide tool in endmilling has been studied with regard to carbide grades and cutting edge sharpenability. Carbide tool's properties were varied by changing the chemical compositions and the carbide particle sizes. Machining test were conducted on a milling machine by endmilling plain carbon steel block. Cutting speed was varied from 31.6m/min to 56.7m/min and feed rate 0.1mm/tooth whereas depth of cut was used constantly on the tests. After test runs, the following conclusions were obtained : (1) There is a great deal of influence in tool failure, when the carbide grades of endmills are changed with the sharpenability of cutting edges. It is found that the sharpenability of cutting edge relate with carbide particle sizes and binder contents. (2) Wear pattern on the tool flank is fine chipping in cutting edges and its chipping process is rapid in the up-endmilling. (3) The difference of the cutting-ability rating of the hot isostatic press treatment tool (N20H) and that of the conventional tool (N20) was not clear.