Fundamental Study on Cutting Mechanism of Different Helix Angles End Mills. Investigation of Cutting Process based on Cutting Tests by 2-Tooth End Mills.

Abstract

This paper deals with the cutting mechanism based on cutting tests by 2-tooth end mills with different helix angles. The results are as follows. ( 1 ) There was a chip area decrease by a low helix angle edge and increase by a high helix angle edge, in the cutting process with no transition period in the end milling. ( 2 ) Behavior of the cutting force is coincident to that of chip area. However, in the cutting process except the transition period, the change in the cutting force is larger than that in the chip area. ( 3 ) Under the cutting conditions, the machined surface from the bottom to 5 or 7 mm is generated by a 41°helix edge due to smaller normal force, and the other part is generated by a 38°helix edge in the same manner. ( 4 ) Light and heavy chips are obtained by the 2-tooth end mill, but the chip weight is lighter for the former and heavier for the latter than each ideal value. ( 5 ) On the assumption that a high helix angle edge cuts a workpiece overmuch in the feed direction based on the results of cutting tests, calculated values of chip weight and cutting force agree with experimental values, respectively.