End mill

Abstract

To provide an end mill capable of dividing chips while maintaining rigidity and sharpness of a cutting edge.SOLUTION: In the end mill 1 having at least the plurality of first helical flutes 11 to 13 helically formed from one end to the other end and the plurality of second helical flutes 21 to 23 helically formed in the opposite direction to the first helical flutes 11 to 13, the first cutting edge group 50 to 52 including the plurality of cutting edges is formed on the rear side in the rotational direction of the end mill 1 with respect to the first helical flutes 11 to 13. The second cutting edge groups 60 to 63 each including the plurality of cutting edges are formed on the rear side in the rotational direction of the end mill 1 with respect to the second helical flutes 21 to 23, the first cutting edge groups 50 to 52 are formed at intervals of the first helical flutes 11 to 13, and the second cutting edge groups 60 to 63 are formed at intervals of the second helical flutes 21 to 23.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an end mill used mainly for cutting the side surfaces of aircraft parts made of CFRP. [Background technology]

[0002] Conventionally, an end mill that has two types of helical flutes, left-handed and right-handed, on its outer periphery has been disclosed as an end mill for milling CFRP (carbon fiber reinforced plastic), which is widely used in aircraft parts, etc. (See Patent Document 1.) These left and right helical flutes each have a cutting edge on the rear side in the rotation direction of the end mill. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7163166 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the end mill disclosed in Patent Document 1 has a peripheral cutting edge with a concave flank on the outer periphery in a cross section perpendicular to the axis, which reduces the rigidity of the cutting edge compared to end mills with a convex curve on the outer periphery like general-purpose end mills.In addition, the reduced rigidity of the cutting edge has caused problems such as delamination and uncut fibers when cutting workpieces containing fibers such as CFRP.

[0005] Therefore, an object of the present invention is to provide an end mill that can break chips while maintaining the rigidity and sharpness of the cutting edge. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the end mill of the present invention is an end mill having at least a plurality of first helical flutes formed in a spiral shape from one end to the other end, and a plurality of second helical flutes formed in a spiral shape in the opposite direction to the first helical flutes.

[0007] In this end mill, a first cutting edge group consisting of multiple cutting edges is formed on the rear side of the first helical flute in the direction of rotation of the end mill, and a second cutting edge group consisting of multiple cutting edges is formed on the rear side of the second helical flute in the direction of rotation of the end mill, the first cutting edge group being formed on every other row of the first helical flute, and each cutting edge forming the first cutting edge group being formed in a stepping stone shape, and the second cutting edge group being formed on every other row of the second helical flute, and each cutting edge forming the second cutting edge group being formed in a stepping stone shape. [Effects of the Invention]

[0008] The end mill of the present invention has rigidity at the cutting edge and exhibits the effect of breaking chips into small pieces while maintaining sharpness. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a partially enlarged perspective view of the end mill 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the end mill 1 of the present invention will be described with reference to the drawings. As shown in Fig. 1, the end mill 1 of the present invention has multiple types of helical flutes formed along the longitudinal direction (axial direction) of the end mill 1. The helical flutes are formed from multiple first helical flutes 11, 12, 13 that are formed in a spiral shape from the tip side of the end mill 1 toward the other end (shank side), and multiple second helical flutes 21, 22, 23 that are formed in the opposite direction to the first helical flutes 11, 12, 13 and are also formed in a spiral shape.

[0011] First cutting edge groups 50, 51, and 52 each consisting of a plurality of cutting edges are formed on the rear side of the first helical flutes 11, 12, and 13 in the rotation direction of the end mill 1. The first cutting edge groups 50, 51, and 52 are formed at intervals of each of the first helical flutes 11, 12, and 13.

[0012] Furthermore, the cutting edges 50, 51, and 52 that form the first cutting edge group are arranged in a stepping-stone pattern as shown in Fig. 1. That is, rather than each cutting edge 50, 51, and 52 being formed one by one along the first helical flute, relief surfaces 71, 72, and 74 that do not have cutting edges are formed between each cutting edge, and each cutting edge is arranged on both sides of the relief surfaces 71, 72, and 74. This is because, in the cross-sectional shape of the end mill, each cutting edge is arranged in a convex shape on the outward side, and relief surfaces are provided between each cutting edge to prevent interference with the cutting edges of these cutting edges. As a result, each cutting edge is arranged in a stepping-stone pattern, which improves the cutting edge rigidity of the end mill.

[0013] Second cutting edge groups 60, 61, 62, and 63, each consisting of a plurality of cutting edges, are formed on the rear side of the second helical flutes 21, 22, and 23 in the rotation direction of the end mill 1. The second cutting edge groups 60, 61, 62, and 63 are formed at intervals of the second helical flutes 21, 22, and 23, as shown in FIG.

[0014] The cutting edges 60, 61, 62, and 63 that form the first cutting edge group are arranged in a stepping-stone pattern as shown in Fig. 1. That is, the cutting edges 60, 61, 62, and 63 are not formed one by one along the second helical flute, but relief surfaces 70 and 73 that do not have cutting edges are formed between the cutting edges, and the cutting edges are arranged on both sides of the relief surfaces 70 and 73.

[0015] This is achieved by arranging each cutting edge in a convex shape on the outward side in the cross section of the end mill, and providing relief surfaces between each cutting edge to prevent interference with the cutting edges of these cutting edges.As a result, each cutting edge is arranged like a stepping stone, which improves the cutting edge rigidity of the end mill.

[0016] As described above, the end mill of the present invention includes a plurality of first helical flutes spirally formed from the end toward the shank, and a plurality of second helical flutes spirally formed in the opposite direction to the first helical flutes. Furthermore, a first cutting edge group consisting of a plurality of cutting edges is formed on the rear side of the first helical flute in the rotational direction of the end mill, and a second cutting edge group consisting of a plurality of cutting edges is formed on the rear side of the second helical flute in the rotational direction of the end mill. The first cutting edge group is formed on every other first helical flute, and each cutting edge forming the first cutting edge group is formed in a stepping-stone shape. Furthermore, the second cutting edge group is formed on every other second helical flute, and each cutting edge forming the second cutting edge group is formed in a stepping-stone shape. With this configuration, the end mill of the present invention exhibits the effect of being able to break chips while maintaining the rigidity and sharpness of the cutting edges. [Explanation of symbols]

[0017] 1 end mill 11~13 First spiral groove 21~23 Second spiral groove 50~52 First cutting edge group 60~63 Second cutting edge group 70~74 Relief surface

Claims

1. An end mill having at least a plurality of first helical flutes formed in a spiral shape from one end to the other end, and a plurality of second helical flutes formed in a spiral shape in the opposite direction to the first helical flutes, wherein a first cutting edge group consisting of a plurality of cutting edges is formed on the rear side of the first helical flute in the rotational direction of the end mill, and a second cutting edge group consisting of a plurality of cutting edges is formed on the rear side of the second helical flute in the rotational direction of the end mill, wherein the first cutting edge group is formed on every other first helical flute, and each cutting edge forming the first cutting edge group is formed in a stepping stone shape, and the second cutting edge group is formed on every other second helical flute, and each cutting edge forming the second cutting edge group is formed in a stepping stone shape.

2. The end mill according to claim 1, wherein a relief surface having no cutting edge is provided between each of the cutting edges forming the first group of cutting edges.

3. The end mill according to claim 1, wherein a relief surface having no cutting edge is provided between each of the cutting edges forming the second group of cutting edges.

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