Abstract
It is known that in dry cutting, temperatures of both work piece and tool will be raised, the work piece softened and therefore cutting resistance decreased. Meanwhile, the tool life will be short and the accuracy of the work piece lower. On the other hand, in wet cutting, temperature changes of both work piece and tool are restrained, the tool life will be a little bit longer and the accuracy will be higher. However, due to the work piece cooling, softening phenomenon of the work piece is restrained resulting in higher cutting resistance in wet cutting in comparison with that in dry one. If the tool is separately be cooled and the work piece is also separately be heated and softened, the softened work piece can be machined by tool with maintained hardness. Therefore the cutting resistance will be very small and the tool life is very long. In this study, both the cooling system of the ball end-mill and the heating system of the cemented carbide work piece were equipped. The ball end-mill was made from the electro-deposited diamond which has function of heat pipe in its body. Materials of the work pieces were SKD11, SKD61 and V10. These work pieces were heated from 373 K to 573 K by an infrared radiation heater. The optimum machining conditions were investigated in some experiments. Then surface roughness, hardness changes of the work piece and the tool life were measured and evaluated. It is concluded from the results that; (1) The cutting resistance was reduced thanks to the softening of the work piece. (2) Tool's temperature changes created by work piece pre-heating process and by heat source generated during cutting duration were restrained by the heat pipe function of the ball end-mill. (3) This system allows to achieve work piece softening and tool's hardness and strength maintenance simultaneously.
