Ball endmill

Abstract

This ball endmill, which comprises alternatingly formed long and short blades, achieves excellent chip discharge performance without sacrificing the blade edge strength in particular at the end-side portion of the endmill body which intersects the axis of the long blades. On the end portion of the endmill body (1) which is rotated around an axis (O), an even number of cutting blades (7) formed spaced in the circumferential direction have a rotation trajectory around the axis (O) which forms a hemisphere. Every other cutting blade (7) in the circumferential direction is a long blade (7A) made to intersect with the axis (O) of the end of the endmill body (1); the other, remaining cutting blades (7) are short blades (7B) the inner peripheral end of which is in a position separated from the axis (O). End gashes (6A) on the long blades (7A) and the end gashes (6B) on the short blades (7B) adjacent in the endmill rotation direction (T) communicate at the end side of the endmill body (1), and, at least on the end side of the endmill body (1), the end gashes (6A) on the long blades (7A) are wider in the circumferential direction than the end gashes (6B) on the short blades (7B).

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.

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