STEP CUTTING TYPE THROWAWAY END MILL

摘要

PURPOSE:To improve the strength of a cutting edge and reduce the cutting resistance by providing a polygonal tip having throwaway tips constituting a main cutting edge with a corner angle of 100-150 deg. in a throwaway end mill. CONSTITUTION:When the step cutting type throwaway end mill of a milling tool uses an equilaterally-octagonal negative tip, 11 throwaway tips 12 are fitted to the outer periphery of a cutter body 11. The fitting positions are displaced by a fixed angle beta (beta=120 deg. in the figure) in the rotary direction, and the rotation radii are made equal to each other. The throwaway tips are arranged at displacement by a fixed quantity Sa in the axial direction, and an outer main cutting edge 13 is fitted at a rake angle alpha against the outer-periphery surface. This cutting edge constitution is further fitted with a tetragonal tip 17 on its bottom section to be used as the end mill. Accordingly, the strength of the cutting edge can be improved and the cutting resistance can be reduced.