End mill

Abstract

To provide an end mill that can suppress occurrence of chatter and burr due to biting of chips, in performing groove-processing of a material to be cut, so-called a hard-to-cut material, such as stainless steel.SOLUTION: An end mill 10 comprises at least a plurality of bottom blades 1, an outer peripheral blade 2 formed spirally along a longitudinal direction, and a torsional groove 4 comprising a rake face 3 formed adjacently to the outer peripheral blade 2. The torsional groove 4 is constituted of a first torsional groove 4a comprising the rake face 3, a second torsional groove 4b formed adjacently to the first torsional groove 4a, and a third torsional groove 4c formed at a frost side in a rotating direction of the end mill 10 adjacently to the second torsional groove 4b, where a rake angle α of the rake face 3 is in a range of 9-11 degrees, in an axially perpendicular section view of the end mill 10.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention mainly relates to an end mill for performing groove machining on a workpiece mainly made of stainless steel, so-called difficult-to-machine material.

Background Art

[0002] Conventionally, in cutting processes such as side machining and groove machining using an end mill, a technique has been disclosed that promotes chip separation from the end mill by suppressing the rubbing of chips generated from the workpiece and providing a coolant (cooling agent) reservoir under the generated chips (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the case of cutting a workpiece mainly made of stainless steel, the space formed under the chips generated by the end mill disclosed in Patent Document 1 becomes narrow, and the effect of chip discharge performance is significantly reduced.

[0005] Therefore, an object of the present invention is to provide an end mill that suppresses chatter and burr generation caused by chip entanglement when performing groove machining on a workpiece mainly made of stainless steel, so-called difficult-to-machine material.

Means for Solving the Problems

[0006] To solve the aforementioned problems, the end mill of the present invention has at least a plurality of bottom cutting edges, an outer cutting edge formed helically along the longitudinal direction, and a helical groove with a rake face formed adjacent to the outer cutting edge, wherein the angles formed between adjacent bottom cutting edges are different from each other, and the helical angles of adjacent helical grooves are also different from each other. The helical groove is composed of a first helical groove with a rake face, a second helical groove formed adjacent to the first helical groove, and a third helical groove formed adjacent to the second helical groove on the front side in the rotational direction of the end mill, and the rake angle of the rake face in a cross-sectional view perpendicular to the axis of the end mill is in the range of 9 to 11 degrees.

[0007] Also, the outer blade and End mill Let L0 be the straight line connecting the central axes, the first intersecting ridge where the first and second helical grooves intersect, and the second intersecting ridge where the second and third helical grooves intersect. Then, starting from the first intersecting ridge, a straight line L1 parallel to the straight line L0 and Starting from the first intersecting ridge R1 The angle formed with the tangent line L11 of the second torsional groove is in the range of 6 to 10 degrees, and the line L2 is parallel to the line L0 starting from the second intersecting ridge. Starting from the second intersecting ridge R2 The angle formed between the third helical groove and the tangent L12 may be in the range of 11 to 100 degrees. [Effects of the Invention]

[0008] The end mill of the present invention has the effect of suppressing vibration and burr formation caused by chip jamming, even when machining grooves in workpieces, mainly stainless steel, which are so-called difficult-to-machine materials. [Brief explanation of the drawing]

[0009] [Figure 1] This is a front view of the end mill 10 of the present invention. [Figure 2] This is a left side view of the end mill 10 of the present invention. [Figure 3] This is a cross-sectional view along line AA shown in Figure 1. [Figure 4] This is a magnified view of section B shown in Figure 3. [Modes for carrying out the invention]

[0010] An embodiment of the end mill of the present invention will be described with reference to the drawings. Figure 1 shows a front view of the end mill 10 of the present invention, and Figure 2 shows a left side view. As shown in Figures 1 and 2, the end mill 10 of the present invention has four bottom cutting edges 1 (1a, 1b, 1c, 1d) and four outer cutting edges 2 (2a, 2b, 2c, 2d) that are continuously formed from the ends (outermost parts) of these bottom cutting edges. Four adjacent helical grooves 4, 4, 4, 4 are formed on these four helical outer cutting edges 2a, 2b, 2c, 2d.

[0011] The four bottom cutting edges 1a, 1b, 1c, and 1d have a so-called unequal division configuration, as shown in Figure 2, where the angles θ1 and θ2 formed between adjacent bottom cutting edges (the central angles between the two lines connecting the outermost part of each bottom cutting edge from the central axis O of the end mill 10) are different from each other. Furthermore, the four outer cutting edges 2a, 2b, 2c, and 2d have a so-called unequal lead configuration, as shown in Figure 1, where the helix angles θ11 and θ12 between adjacent helix grooves 4, 4 are also different from each other.

[0012] Next, the shape of the specific outer cutting edge 2b and the groove 4 connected thereto that constitute the end mill 10 will be described. Figure 3 shows a cross-sectional view of the end mill 10 shown in Figure 1 along line AA, and Figure 4 shows an enlarged view of the circle B portion of Figure 3 (outer cutting edge 2b and rake face 3b). As shown in Figures 3 and 4, the end mill 10 of the present invention has helical grooves 4, 4, 4, 4 formed on the rotational direction side (counterclockwise side in the drawing) of each outer cutting edge 2a, 2b, 2c, 2d, and rake faces 3a, 3b, 3c, 3d formed on each outer cutting edge 2a, 2b, 2c, 2d.

[0013] As shown in Figure 4, a helical groove 4 is formed on the outer peripheral cutting edge 2b toward the central axis O. This helical groove 4 consists of a first helical groove 4a, a second helical groove 4b, and a third helical groove 4c, extending from the outer peripheral side of the end mill 10 toward the central axis O. The first helical groove 4a is the helical groove located on the outermost peripheral side of the end mill 10 among the first to third helical grooves 4a, 4b, and 4c, and has a rake face 3b formed by the outer peripheral cutting edge 2b.

[0014] In other words, the first helical groove 4a is formed to open towards the rear in the rotational direction of the end mill 10 (counterclockwise direction in Figure 4), with reference to a straight line L0 that extends perpendicularly from the tangent to the circumscribed circle C0 of the end mill 10 on the outer cutting edge 2b. Furthermore, the rake angle α of the rake face 3b can be defined as the angle between the straight line L0 connecting two points on the outer cutting edge 2b and the central axis O and the tangent L10 to the outer cutting edge 2b, as shown in Figure 4.

[0015] The second helical groove 4b is a helical groove located midway between the first helical groove 4a and the third helical groove 4c, that is As shown in Figure 4, the first helical groove 4a is connected to the outer circumference of the end mill 10, and the third helical groove 4c is connected to the central axis O side. In other words, it is formed continuously with the first helical groove 4a, and is formed to open towards the rear in the rotational direction of the end mill 10 (counterclockwise direction in Figure 4), with reference to a straight line L0 that extends perpendicularly from the tangent to the circumscribed circle C0 of the end mill 10 at the outer cutting edge 2b.

[0016] Furthermore, at the first intersecting ridge R1 where the first torsional groove 4a and the second torsional groove 4b intersect, the angle β formed by the line L1 parallel to the line L0 originating from the first intersecting ridge R1 and the tangent line L11 of the second torsional groove 4b is in the range of 6 to 10 degrees.

[0017] The third helical groove 4c is the helical groove located on the front side in the rotational direction of the end mill 10 among the first to third helical grooves 4a, 4b, and 4c, and is connected to the second helical groove 4b on the outer circumference side of the end mill 10. That is, it is formed continuously with the second helical groove 4b and is formed to open forward in the rotational direction of the end mill 10 (counterclockwise direction in Figure 4) with respect to a straight line L0 that extends perpendicularly from the tangent to the circumscribed circle C0 of the end mill 10 at the outer cutting edge 2b.

[0018] Furthermore, at the second intersecting ridge R2 where the second torsional groove 4b and the third torsional groove 4c intersect, the angle γ formed by the line L2, which is parallel to the line L0 originating from the second intersecting ridge R2, and the tangent line L12 of the third torsional groove 4c is in the range of 11 to 100 degrees.

[0019] The end mill of the present invention is composed of a twist groove formed by the first to third twist grooves. In particular, the second twist groove is formed so as to open toward the rear side in the rotation direction of the end mill with respect to a straight line extending from the outer peripheral edge toward the central axis. Therefore, a space can be secured directly below the chips generated by cutting, and the dischargeability of continuously generated chips can be improved.

Explanation of Reference Numerals

[0020] 1(1a,1b,1c,1d) Bottom edge 2(2a,2b,2c,2d) Outer peripheral edge 3 Relief surface 4 Twist groove 10 End mill L0 Straight line connecting the outer peripheral edge and the central axis L1,L2 Straight lines parallel to the straight line L0 L11,L12 Tangent lines O Central axis R1 First intersection ridge line R2 Second intersection ridge line α Relief angle β Angle formed by the straight line L1 and the straight line L11 γ Angle formed by the straight line L2 and the straight line L12 θ1,θ2 Angle formed between the bottom edges θ11,θ12 Twist angle

Claims

[Claim 1] An end mill having at least a plurality of bottom cutting edges, an outer cutting edge formed helically along the longitudinal direction, and a helical groove with a rake face formed adjacent to the outer cutting edge, wherein the angles between adjacent bottom cutting edges are different from each other, and the helical angles of adjacent helical grooves are different from each other, wherein the helical groove is composed of a first helical groove with a rake face, a second helical groove formed adjacent to the first helical groove, and a third helical groove formed adjacent to the second helical groove on the forward side in the rotational direction of the end mill, wherein in a cross-sectional view perpendicular to the axis of the end mill, the rake angle of the rake face is in the range of 9 to 11 degrees. In a cross-sectional view perpendicular to the axis of the end mill, if L0 is the straight line connecting the outer cutting edge and the central axis of the end mill, R1 is the first intersecting ridge where the first helical groove and the second helical groove intersect, and R2 is the second intersecting ridge where the second helical groove and the third helical groove intersect, then the angle β between the straight line L1, which starts from the first intersecting ridge R1 and is parallel to the straight line L0, and the tangent line L11, which starts from the first intersecting ridge R1, is in the range of 6 to 10 degrees, and the angle γ between the straight line L2, which starts from the second intersecting ridge R2 and is parallel to the straight line L0, and the tangent line L12, which starts from the second intersecting ridge R2, is in the range of 11 to 100 degrees.

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