Arc head end mill

Abstract

Chipping of cutting edge due to weakened corner edge and roughened cut surface due to chipping can be prevented. At the lower end corner of a flute (4) at the outer periphery of an end mill body (1) which faces the direction of rotation (T) about an axis (O) is provided a rake face (11) with a corner edge (12) at its outer edge capable of forming a convex shape when rotated about the axis (O). Radially inside of the rake face (11) is provided a gash (7) having a bottom rake face (8) which faces the direction of rotation (T). The bottom rake face has a bottom edge (9) at the end of the end mill extending radially inwardly from the corner edge (12). The line (L) of intersection between the rake face (11) and the rake face (8) ends at the point (Q) which locates radially inside of the center (S) of the corner edge (12) and axially rearward of the lowest point (P) of the corner edge (12).

Description

technical field [0001] The present invention relates to a circular arc head end mill in which a convex arc-shaped cutting edge is formed on the outer periphery of the front end of the end mill main body. Background technique [0002] As such a circular arc nose end mill, for example, Patent Document 1 proposes a circular arc nose end mill formed by forming a main cut surface on the inner peripheral side of the front end portion of the wall surface of the chip discharge flute facing the tool rotation direction, and The bottom edge is formed at the front end of the main notch surface, and the sub-notch surface is formed on the outer peripheral side of the main notch surface in such a way that the step portion retreats relative to the main notch surface, and a substantially convex arc is formed from the front end of the sub-notch surface to the outer periphery. The circular arc edge of the cutter head is connected with the outer peripheral side of the bottom edge. [0003] In ...

AI Technical Summary

Problems solved by technology

[0007] However, on the one hand, if a step portion or an intersecting ridge line intersecting the arc edge of the cutter head is formed on the rake face in this way, because the rake angle changes rapidly on both sides of the step portion or the intersecting ridge line, Therefore, the load applied during cutting also fluctuates and the strength of the blade also changes.

Therefore, especially in the arc-end end mill described in Patent Document 2, when the above-mentioned intersecting ridgelines intersect at the approximate center of the arc-radius edge of the cutter head, there is an effect on the side where the edge strength is weak or the cutting load is relatively large. Worry about damage to the arc edge of the cutter head on one side

[0008] And, if the rake angle changes rapidly in the middle of the arc edge of the cutter head when the step portion or the intersecting ridgeline intersects in this way, the chips generated across the step portion or the intersecting ridgeline are generated in a tearing manner, so it can be As mentioned above, the handling property is improved by dividing the chip, but there is also a possibility that streaky traces generated by the chip being torn remain on the processed surface of the workpiece, and the roughness of the processed surface may be damaged.

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