AlTiN코팅공구를 이용한 플라스틱 금형강의 절삭특성에 관한 연구

Abstract

In this research, KP-4, one of the plastic mold steels, was coated with the AlTiN from one layer to four layers by the PVD method in the Φ 8mm cemented carbide ball end mill. Coated KP-4 was processed with various conditions. For example, in Φ 60 circular material of inner and outer surface and material's slope of 15°, 30° and 45° the spindle rotation speed was changed from 10,000rpm to 16,000rpm, the tool feeding speed was changed from 1,300mm/min to 1,700mm/min, the depth of cut was also changed from 0.3mm to 0.9mm, and etc. Cutting component force according to the coating layer number, surface roughness, and the wear of tool were studied. According to the results, some important conclusions were found as follows:

1. When slope angle condition(15°, 30°, 45°) was chosen as 15°, the largest cutting component force by material shape is showed. In case of the curved surface processing, the cutting component force in inner surface, smearins appeared in, is higher than outer surface. the cutting component force according to the processing direction is higher in the down ward direction because of the over cut.

2. The larger slope angle, the lower surface roughness by material shape showed and surface roughness of inner surface is higher than outer surface. The difference of the surface roughness according to the processing direction is 0.1㎛ between up and down ward. The difference of by a number of the AlTiN coating layers is 0.08㎛.

3. According to the coating results, AlTiN was coated from one layer to four layers in cemented carbide ball end mill, 3rd coating layer of AlTiN coating layers has the best mechanical properties. The quantity of the flank wear according to the shape of the material was the fastest in case of the material's slope of 15°, and then, the wear of tool was proceeded as a sequence of the material's slope of 30° and 45°. In the curved surface, rate of wear in inner surface is more faster than outer surface.

4. The wear by AlTiN coating tool layers showed a good result in 1st, 4th, 2nd, 3rd layer order. Especially, the wear condition is stable state in 3rd coating layer in spite of the processing time for more than 90 minutes.