Ball end mill

Abstract

A ball end mill, which includes long and short cutting edges alternately formed, obtains excellent chip discharge performance without sacrificing the strength of cutting edges, particularly, at front end portions of the long cutting edges of an end mill body that intersects with the axis. An even number of cutting edges 7 are formed at intervals in a circumferential direction on a front end portion of an end mill body 1 rotated about an axis O and of which rotation trajectories formed around the axis O form the shape of a hemisphere. The cutting edges 7, which are adjacent to each other in the circumferential direction with one cutting edge interposed therebetween, are long cutting edges 7A that intersect with each other on the axis 0 on the front end portion of the end mill body 1, and the other cutting edges 7, which are adjacent to each other in the circumferential direction with one cutting edge interposed therebetween, are short cutting edges 7B that include inner peripheral ends at positions distant from the axis O. A gash 6A of the long cutting edge 7A and a gash 6B of the short cutting edge 7B, which is adjacent to the long cutting edge in an end mill rotation direction T, connect with each other on a front end side of the end mill body 1. The gash 6A of the long cutting edge 7A is wider than the gash 6B of the short cutting edge 7B in the circumferential direction on at least the front end side of the end mill body 1.

Description

technical field [0001] The present invention relates to a ball end mill with an even number of edges, in which a hemisphere with a center on the axis is formed at intervals in the circumferential direction on the front end of the end mill body rotating around the axis. Shaped even-numbered cutting edges. Background technique [0002] As such an even-numbered ball end mill, Patent Document 1 proposes a six-blade ball end mill in which six ball end mills are formed at the front end of the end mill main body, wherein the Every other three ball-end cutting edges are long ball-end cutting edges (long cutting edges) that intersect on the axis of the front end of the end mill body, and the remaining three ball-end cutting edges have an inner peripheral end at a position away from the axis. Short ball point edge (short edge). [0003] In this type of ball nose end mill, compared to a ball nose end mill in which all six ball noses are long ball noses, it is possible to easily form ...

AI Technical Summary

Problems solved by technology

[0006] Furthermore, on the basis of three prolong ball-point blades, the notched surface forms a space more receding than the hemisphere formed by the rotation trajectory of the long ball-point blade on the inner peripheral side than the inner peripheral end of the short ball-point blade. , and the capacity of the chip flute for discharging chips is ensured through this space, but if the notch surface is enlarged to ensure a larger chip flute capacity, the notch surface reaches the distance between the long ball-end edge and the front end side of the end mill body. Partially connected front flanks, especially at the part where the long ball end edge intersects on the axis, cannot ensure the wall thickness of the end mill body on the rear side of the end mill rotation direction, resulting in a decrease in the strength of the tool tip. Easy to cause damage, etc.

Images