AN END MILL AND A CUTTING INSERT USED FOR THE SAME

摘要

The present invention has a shank portion, a head portion extended from an end of the shank portion, a bottom cutting edge formed on a bottom surface of the head portion, a side cutting edge formed on a side surface of the head portion and connected to the bottom cutting edge, and a rake surface and a clearance surface extending from the bottom cutting edge. The bottom cutting edge has a first bottom cutting edge and a second bottom cutting edge. When viewed from the front of the end mill, the first bottom cutting edge extends from a central axis of the head portion to an intersection formed with the second bottom cutting edge in a direction away from the shank portion. The second bottom cutting edge extends straight at an angle from the intersection formed with the first bottom cutting edge to an intersection formed with the side cutting edge in a direction towards the shank portion. The rake surface forms a positive rake angle with respect to the central axis of the head portion.