Effect of tool angles on the chips generated during milling of wood by straight router-bits

摘要

The effect of tool angles on the shapes of chips generated by parallel-to-grain and end-grain milling was explored for China fir and maple under fixed spindle and feed speeds and cutting depth. The milling path was up-milling by straight router-bitswith a diameter of 12 mm. The chip shapes could be distinguished as five types: spiral, splinter. flow, thin, and granules or powder. The flow and thin chips were generated most often (on a weight percentage basis) for all tool angles investigated for parallel-to-grain and end-grain milling of China fir and maple. More granule chips were produced with parallel-to-grain milling than with end-grain milling for both woods. The measured chip thickness (t') was thicker than the calculated thickness (t_(max)). Thicker and longer maple chips were produced by end-grain milling than by parallel-to-grain milling. The tool geometries of 40 deg/15 deg (sharpness of the angle-rake angle). 50 deg/15 deg, and 60 deg/15 deg for China fir and 40 deg/25 deg, 50 deg/5 deg, and 60 deg/5 deg for maple produced relatively more flow chips with parallel-to-grain milling. Furthermore, the tool geometries of 40 deg/5 deg, 50 deg/15 deg and 60 deg/25 deg produced more flow chips (weight percentage) by end-grain milling of China fir and maple.