A study on tapping wrought aluminum (2nd report)

Abstract

Being continued from the previous report, the tapping machinability of wrought aluminum alloys, i.e., 17S-F, 24S-F, and 56S-F, were discussed in regard to the relation between the theoretical analysis and experimental value of tapping torque, chips formation and its effects, built-up edge, etc.The results were summarized as follows.Orthogonal cutting tests, which were regarded as cutting mechanism approximate to tapping, were conducted in turning to obtain the specific cutting resistance of the material. Then, the theoretical tapping torque was calculated. As the results, the theoretical value of 24S-F was almost equal to the experimental value, but in 17S-F and 56S-F, there was a great difference between the both values. The above results may be mainly due to the factthat the torque was greatly affected by chips removal in tapping. In other words, 24S-F formed finely divided chips which were easy to be removed. However, the chips of 17S-F and 56S-F were filled and to select the tapflute and in many cases they formed the shape of flute. In consequence, it would be necessary compressed in the having proper twisted flute, shape of flute, clearance angle, etc. according to the materials.