Roughing end mill and insert for a roughing end mill

A roughing end mill comprising:

• an end mill body which is rotatable around an axis of the end mill body;
• and
• a plurality of inserts which are placed on an outer circumference of the end mill body at a predetermined distance from each other in the direction of the axis of the end mill body, wherein
• the plurality of inserts form a plurality of insert rows which are provided in a circumferential direction of the end mill body,
• at least the inserts, excluding the inserts at a tip of a distal end of an insert row, are positioned so as to be offset in the direction of the axis of the end mill body from each other in the different insert rows which are mutually adjacent in the circumferential direction,
• the inserts, excluding the inserts at a tip of a distal end of an insert row, are provided with waveform cutting edges which face towards an outer circumferential side of the end mill body,
• the waveform cutting edges have an arc shape made up of smoothly continuous concave curves and convex curves,
• a first row of a plurality of insert rows includes first inserts, a second row of a plurality of insert rows includes second inserts which are shifted in the direction of the axis of the end mill body with respect to the first inserts such that the waveform cutting edges of the adjacent first inserts and the waveform cutting edges of the adjacent second inserts do not overlap and form a first waveform cutting edge row whose phase is smoothly continuous on a rotation trajectory of the first and second inserts around the axis of the end mill body,
• a third row of a plurality of insert rows includes third inserts, a fourth row of a plurality of insert rows includes fourth inserts which are shifted in the direction of the axis of the end mill body with respect to the third inserts such that the waveform cutting edges of the adjacent third inserts and the waveform cutting edges of the adjacent fourth inserts do not overlap and form a second waveform cutting edge row whose phase is smoothly continuous on a rotation trajectory of the third and fourth inserts around the axis of the end mill body,
• outlines of the first and second waveform cutting edge rows are identical,
• profiles of the rotation trajectories of the first and second waveform cutting edge rows are out of alignment with each other in the direction of the axis of the end mill body,
• the waveform cutting edges of the first, second, third and fourth inserts have the same shape and size as each other and have waveform shapes with a uniform wavelength, and
• the rotation trajectory of the first inserts partially overlap the rotation trajectory of the third inserts in the direction of the axis of the end mill body.