End mill

Abstract

To provide an end mill for suppressing generation of a step transferred to a processed face in processing a lateral face (wall surface) to a material to be cut.SOLUTION: An end mill 10 having a plurality of side peripheral blades 1 spirally formed along a rotation axis O direction, and a shank 20 as a gripping part is such that: the side peripheral blade 1 is formed from a front side peripheral blade 2 in which a distance d2 from the rotation axis O to a blade tip 12 is constant, and a rear side peripheral blade 3 in which a distance d3 from the rotation axis O to a blade tip 13 changes; and the rear side peripheral blade 3 allows the distance d3 from the rotation axis O to the blade tip 13 to be reduced from the tip side of the end mill 10 to the shank 20 side.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an end mill for performing side machining on a workpiece. [Background technology]

[0002] Conventionally, end mills with cutting edges (circumferential cutting edges) and a tip diameter larger than the shank diameter are excellent for side machining, as disclosed in Patent Documents 1 to 3. These end mills are formed with a convex curved shape in the radial direction, which allows for a good machined surface to be obtained on the workpiece. Figure 2 shows a schematic cross-sectional view of a workpiece that has been machined using a conventional end mill. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-15025 [Patent Document 2] Patent No. 6247807 [Patent Document 3] Patent No. 6892037 Summary of the Invention [Problem to be solved by the invention]

[0004] However, because side machining is performed only using the convex curved portion at the tip of the end mill, the pitch H (the distance between the first and second machining stages) of movement in the axial direction of the end mill becomes small, resulting in a longer machining time.On the other hand, if the axial pitch H of the end mill is increased, uncut areas (uncut portions) K1 and K2 shown in Figure 2 are generated, causing the problem that the end mill gets caught at part X in Figure 2 during side machining.

[0005] To address this issue, when side machining is performed using a general-purpose square end mill, the entire side cutting edge of the square end mill 100 is used to perform the side machining, as shown in Figures 3 and 4, so the square end mill 100 is tilted due to the overload during cutting. As a result, when the square end mill 100 is tilted while performing side machining, uncut areas K3 and K4 are left on the workpiece, and the side cutting edge on the shank side of the square end mill 100 catches on the workpiece (particularly the steps of the uncut areas K3 and K4) at part Y shown in Figure 4.

[0006] Therefore, an object of the present invention is to provide an end mill that suppresses the occurrence of steps that are transferred to the machined surface when machining the side (wall) surface of a workpiece. [Means for solving the problem]

[0007] The end mill of the present invention has a plurality of side cutting edges formed spirally along the rotation axis direction and a shank that serves as a gripping portion, and the side cutting edges are formed from a front side cutting edge whose distance from the rotation axis to the cutting edge is constant and a rear side cutting edge whose distance from the rotation axis to the cutting edge varies. In this case, the distance from the rotation axis to the cutting edge of the rear side cutting edge can be made smaller from the tip side of the end mill toward the shank side.

[0008] The rear peripheral blade can also be divided into a first rear peripheral blade in which the distance from the rotation axis to the cutting edge decreases linearly, and a second rear peripheral blade in which the distance from the rotation axis to the cutting edge decreases quadratically. [Effects of the Invention]

[0009] The end mill of the present invention has the effect of suppressing the occurrence of steps that are transferred to the machined surface when machining the side surface (wall surface) of a workpiece. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic projection view of an end mill 10 according to an embodiment of the present invention. [Figure 2]FIG. 1 is a schematic cross-sectional view of a workpiece that has been cut using a conventional end mill. [Figure 3] FIG. 1 is a schematic diagram showing a side surface machining mode using a conventional end mill 100. [Figure 4] FIG. 1 is a schematic diagram showing a side surface machining mode using a conventional end mill 100. DETAILED DESCRIPTION OF THE INVENTION

[0011] The end mill of the present invention will be described with reference to the drawings. Fig. 1 shows a schematic projection of the tip of an end mill 10 according to one embodiment of the present invention. The end mill 10 of the present invention has a plurality of side cutting edges 1 formed spirally along the direction of the rotation axis O, and a shank 20 that serves as a gripping portion. The side cutting edges 1, front side cutting edge 2, and rear side cutting edge 3 will be described in detail below.

[0012] 《Side peripheral blade 1》 The side cutting edge 1 is a spiral cutting edge formed in the longitudinal direction along the rotation axis O around the periphery of the end mill 10. The end mill 10 of this embodiment is formed with a plurality of side cutting edges 1. In addition, as shown in FIG. 1 , the side cutting edges 1 are divided into a front side cutting edge 2 and a rear side cutting edge 3 depending on the distance from the rotation axis O to the cutting edge of the side cutting edge 1.

[0013] 《Front side circumferential blade 2》 The front peripheral cutting edge 2 is located opposite the shank 20 as shown in FIG. 1 and is a side cutting edge formed on the tip side of the end mill 10, and the distance d2 from the rotation axis O to the cutting edge 12 is constant. This distance d2 is larger than half the shank diameter of the end mill 10 as shown in FIG. 1. Therefore, the diameter of the front peripheral cutting edge 2 is larger than the diameter of the shank 20 of the end mill 10. In addition, by making the longitudinal dimension (length) of the front peripheral cutting edge 2 longer than the rear peripheral cutting edge described below, side machining of the workpiece can be performed efficiently.

[0014] 《Backward circumferential blade 3》 The rear peripheral cutting edge 3 is a side cutting edge formed on the shank 20 side of the end mill 10, and the distance d3 from the rotation axis O to the cutting edge 13 decreases from the tip side of the end mill 10 toward the shank 20 side. The rear peripheral cutting edge 3 can also be divided into a first rear peripheral cutting edge 3A in which the distance d3a from the rotation axis O to the cutting edge 13A decreases linearly, and a second rear peripheral cutting edge 3B in which the distance d3b from the rotation axis O to the cutting edge 13B decreases quadratically.

[0015] 《1st rear peripheral blade 3A》 The first rear-side peripheral cutting edge 3A is a side cutting edge that forms part of the rear-side peripheral cutting edge 3 and is formed contiguous with the aforementioned front-side peripheral cutting edge 2. The first rear-side peripheral cutting edge 3A is formed so that the distance d3a from the rotation axis O of the end mill 10 to its cutting edge 13A decreases linearly. That is, when the end mill 10 rotates, the trajectory of the cutting edge 13A of the first rear-side peripheral cutting edge 3A is linear, as shown in FIG. 1. For example, the angle θ formed by the virtual line L0 of the rotation axis O of the end mill 10 and the virtual line L1, which is the trajectory of the cutting edge 13A of the first rear-side peripheral cutting edge 3A, can be set arbitrarily within the range of 5° to 30°. Therefore, after the workpiece is cut by the first rear-side peripheral cutting edge 3A of the end mill 10, the workpiece has a tapered chamfered shape.

[0016] 《Second rear peripheral blade 3B》 The second rear-side peripheral cutting edge 3B is a side cutting edge that forms part of the rear-side peripheral cutting edge 3 and is formed contiguous with the first rear-side peripheral cutting edge 3A. The second rear-side peripheral cutting edge 3B is formed so that the distance d3b from the rotation axis O of the end mill 10 to its cutting edge 13B decreases quadratically. That is, when the end mill 10 rotates, the trajectory of the cutting edge 13B of the second rear-side peripheral cutting edge 3B becomes a curved shape as shown in FIG. 1. For example, the trajectory of the cutting edge 13B of the second rear-side peripheral cutting edge 3B can be set as an arc with an arbitrary radius of curvature R centered at a specific position within the end mill 10. Therefore, after the workpiece is cut by the second rear-side peripheral cutting edge 3B of the end mill 10, the workpiece has an R-chamfered shape.

[0017] As described above, the end mill of the present invention has multiple side cutting edges formed spirally along the rotation axis direction, and the side cutting edges are composed of a front side cutting edge with a constant distance from the rotation axis to the cutting edge and a rear side cutting edge with a variable distance from the rotation axis to the cutting edge. Furthermore, by providing the rear side cutting edges with a first rear side cutting edge that linearly reduces the distance from the rotation axis to the cutting edge and a second rear side cutting edge that quadratically reduces the distance from the rotation axis to the cutting edge, it is possible to suppress the occurrence of steps transferred to the machined surface when machining the side (wall) of a workpiece. [Explanation of symbols]

[0018] 1 Side peripheral edge 2 Front peripheral edge 3 Rear peripheral edge 3A 1st rear peripheral blade 3B 2nd rear peripheral blade 10 End mill 12 Cutting edge 13A cutting edge 13B cutting edge 20 shank d2 Distance from the rotation axis to the cutting edge d3a Distance from the rotation axis to the cutting edge d3b Distance from the rotation axis to the cutting edge O Rotation axis

Claims

1. An end mill having a plurality of side cutting edges formed spirally along the direction of the rotation axis and a shank which serves as a gripping portion, wherein the side cutting edges are formed from a front side cutting edge whose distance from the rotation axis to the cutting edge is constant, and a rear side cutting edge whose distance from the rotation axis to the cutting edge varies.

2. 2. The end mill according to claim 1, wherein the distance from the rotation axis to the cutting edge of the rear peripheral cutting edge decreases from the tip side of the end mill toward the shank side.

3. The end mill described in claim 2, characterized in that the rear side peripheral cutting edge comprises a first rear side peripheral cutting edge whose distance from the rotation axis to the cutting edge decreases linearly, and a second rear side peripheral cutting edge whose distance from the rotation axis to the cutting edge decreases quadratically.

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