切削速度の切削に及ぼす影響
切削における表面仕上について
1955 年 21 巻 242 号 p. 141-145
詳細
1955 年 21 巻 242 号 p. 141-145
All of the major factors of surface roughness can be attributed to one or combinations of four elements, such as (1) feed marks, (2) worn cutting edge, (3) built-up-edge, (4) rigidity of machine tools. The feed marks are the result of feed and tool nose radius combining to form the gross variations in a generated surface. They say that in the case of rather large feeds the experimental relationship Hm=f2/8R agrees with actual surface roughness, where Hm, f and R are the maximum height of machined surface, feed and nose radius respectively However the relationship does not necessarily hold in a wide combination of feeds and nose radius. In fact, according to the tests, it was proved to be rather inconsistent or unreasonable in some cases.
With regard to the worn cutting edge, it affects the roughness considerably in the case of form cutting. Assuming that the cutting edge is free from built-up-edge, the irregularities on the machined surface are the printed patterns of the cutting edge.
The third factor, built-up-edge is the most serious, because more or less it is found almost on every machined surface and it is not so easy to control practically.
Rigidity of machine tools is also an important factor through chatter marks, but it is the problem of machine or tool system, so that it is not treated with in this report. This report treats with mainly the two factors of feed marks, and built-up-edge. Concerning the feedmarks, theoretical formulas of the average surface roughness Havg were derived through geometrical computations of feeds, nose radius, end cutting edge angles and side cutting edge angles. According to the comparison between the theoretical formulas and the experimental results, they hold very well in the case of the metals free from built-up-edge, but a considerable deviation could be found for such metals as steels producing heavy built-up-edge. The next step was to examine the speed effect upon built-up-edge or surface roughness which is considered to be the most effective to suppress built-up-edge.
