tailieunhanh - Metal Machining - Theory and Applications Episode 2 Part 1

Tham khảo tài liệu 'metal machining - theory and applications episode 2 part 1', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Non-orthogonal three-dimensional machining 193 Table Values of the coefficients x 1 x 2 yy3 ffi i 0 to 4 and t1e 3-4 x 1 x 2 y 3 rn 1 - sin Y d f sin Y cos Ytan n p rn 1 sin p cos Y cos Y c n ff0 ff1 sin 1 V I- Y . -1 f X d - rn cos n c rn sin Y n c n c sin-1 sin Y n c - c --- c rn c rn cos Y ffl ff3 . -U f . -U f n c sin 1 sin Y n c - sin ff0 - n c I n c sin 1 sin Y n c - sin n c rn rn ff4 t1e Ớ3-4 n .1 f - Y sin 1 2 2rn rn cos n c - ff f cos n c Y - rncos n c- Ỡ fcos n c Y 2-f2- 2rnfcos Y ff 2 ip p 1 sin p cos y sin k f2 sin k cos y r r - I rJ cos - 1 while for cases 2 3 and 4 I- 2 cos p f 1 1 2 4uc d - rn f r n sin f 14r2n - f 21 2rn 4 Auf the projection onto the rake face along the cutting direction of the uncut chip cross-section area is readily shown to be the division of Auc by the z component of eZ x in equation 4uc 4f cos ls cos an Predictions from three-dimensional models The relations from the previous sections may finally be used in the prediction of chip flow direction and cutting force components. Colwell s 1954 approach and the energy approach initiated by Usui Usui et al. 1978 Usui and Hirota 1978 also Usui 1990 will particularly be developed and compared with experiments. 194 Advances in mechanics Colwell s geometrical model The chip flow direction h c in the x - y plane is assumed to be perpendicular to the projected chord AD joining the extremities of the cutting edge engagement Figure in the x - y plane. It is readily found by trigonometry for the four cases shown in Figure . For Case 1 Figure a f cos2 y cos p tan h c ------------------------------------------------- d - rn cos p rn sin y cos y - f cos2 y sin p while for Cases 2 3 and 4 in terms of 04 given in Table r 1 - cos 04 cos y tan hc --------------- ---------------- d rn sin y sin 04 cos y - 1 Then from equation cos an tan h c sin 1s sin an c cos ls This result alone is not sufficient for predicting machining forces .