Каталог Dormer Pramet фрезерование 2021 - 2022 - страница 770

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9 WORKING CONDITION WHEN MILLING As stated above, chip thickness h changes during a single revolution thickness hm is dependent on the type of milling cutter and on en- depending on the angle j in line with the formula hj = fz × sinj. gagement conditions, particularly the ratio of ae/DC, feed per tooth Maximum chip thickness with steady fz is reached within the axis of fz and naturally also on the entering angle KAPR – kr. The following the milling cutter. The average thickness of a chip (hm) removed by figure shows illustrative examples. one tooth during one revolution is calculated as the height of a rec- tangle with the same area as the area under a sine curve relative to the radial depth of cut ae. Average chip a b c d e hj hj = fz .sin j hj hj = fz .sin j hj hj = fz .sin j hj hj = fz .sin j hj hj = fz .sin j hm fz hm fz hm fz hm fz hm fz hm hm = 0,64 . fz hm hmhm hm h1 = 0 h2 = 0 h'1 > 0 h'2> 0 h'‚1> 0 h''2= 0 h'1 > 0 h'2> 0 h''1> 0 h''2= 0 hmax = fz hmax = fz hmax = fzvff vfvfjjj hm a x= fz f vf fz vfjDC vc DC vc DC DC fvc vc DC jvc a e= DC ae m ae ae ae Average chip thickness hm for milling (with the centre) in accordance with figure a, b, d is calculated based on the formula: ae hm = fz . sin k r 57.3 DC . arcsin . aeDC Average chip thickness hm for machining with the side of the milling cutter (figure c, e) is calculated based on the formula: hm = fz . sin kr . 114.6 . aeDC . arccos . 1-2ae DC For milling with the side of the cutter in line with figure e, where the ae/DC ratio is very low < (0.2), average chip thickness hm can be calculated using the simplified formula: hm = fz sin kr aeDC Where: hm Is average chip thickness [mm] fz Feed per tooth [mm/tooth] ae Radial depth of cut [mm] DC Diameter of the milling cutter [mm] kr Entering angle of the main cutting edge (KAPR) [°] 769