Abstract
Hobbing is a kind of plain milling, in which the sectional area of a chip is continuously changing during cutting. Hob wear is considerably affected by the chip length and the thickness. In this paper, after developing a method to divide the cutting length of a chip into four equal parts, investigation were carried out on the distribution ratio of hob wear when cutting each of the parts in the cases of dry cutting, MQL system and flood using TiN- and (Al,Ti)N-coated tools. Experiments were conducted by simulating hobbing by fly tool cutting on a milling machine. As a consequence, the following points were clarified : (1) When using the TiN-coated tool, the distribution ratio of wear is greatest at the end of producing a chip in the four parts in the cases dry cutting and MQL system. However, it is almost the same in the four parts in the case of flood. (2) With the (Al,Ti)N-coated tool, the distribution ratio of wear decreases from the beginning to the end of cutting a chip in the cases of dry cutting and MQL system, but in the case of flood, it shows almost the same value in the four parts.
