CN112930245B

CN112930245B - Method for manufacturing end mill

Info

Publication number: CN112930245B
Application number: CN201980070272.XA
Authority: CN
Inventors: 中市诚; 仲井宏太; 藤井诚
Original assignee: Shengu Machinery Co ltd; Nitto Denko Corp
Current assignee: Shengu Machinery Co ltd; Nitto Denko Corp
Priority date: 2018-10-24
Filing date: 2019-09-17
Publication date: 2024-07-05
Anticipated expiration: 2039-09-17

Abstract

The present invention provides a method for manufacturing an end mill capable of suppressing warpage of a cutting edge and capable of attaching the cutting edge to a main body well. The method for manufacturing the end mill of the invention comprises the following steps: cutting a cutting edge forming piece of a predetermined shape from a base material having a base portion made of a superhard material and a sintered diamond layer provided on one surface of the base portion by electric discharge machining or laser machining; cutting the base of the cutting edge forming piece to reduce the thickness of the base, thereby obtaining a cutting edge; and mounting the cutting edge to the body.

Description

Method for manufacturing end mill

Technical Field

The present invention relates to a method for manufacturing an end mill.

Background

End mills are widely known as one of the cutting tools. Typically, an end mill has a body that rotates about a rotation axis and a cutting edge attached to a surface of the body.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication 2016-182658

Disclosure of Invention

Problems to be solved by the invention

A cutting edge having a base made of a superhard material and a sintered diamond layer provided on one surface of the base has been studied as a cutting edge of an end mill. When such a cutting edge is cut from a base material and attached to an end mill body, the cutting edge may warp during cutting, and attaching the cutting edge to the body may be difficult due to the warp.

The present invention has been made to solve the above-mentioned conventional problems, and has as its main object: provided is a method for manufacturing an end mill, wherein the warping of a cutting edge can be suppressed and the cutting edge can be satisfactorily attached to a body.

Means for solving the problems

The inventors know that: since the heat shrinkage is different between the base side made of the superhard material and the sintered diamond layer side due to the laminated structure, warpage occurs due to heat generated when cutting the base material. Moreover, it was found that: the present invention has been accomplished by cutting a base material made of a superhard material to be thicker than usual, and then cutting the base material, whereby a cutting edge can be produced in which warpage of the cutting edge occurring during cutting is suppressed.

The method for manufacturing the end mill of the invention comprises the following steps: cutting a cutting edge forming piece of a predetermined shape from a base material having a base portion made of a superhard material and a sintered diamond layer provided on one surface of the base portion by electric discharge machining or laser machining; cutting the base of the cutting edge forming piece to reduce the thickness of the base, thereby obtaining a cutting edge; and attaching the cutting edge to the body.

In one embodiment, the thickness of the cutting edge forming piece is 1.6mm to 3.2mm, and the thickness of the cutting edge is 0.7mm to 1.6mm.

In one embodiment, the thickness of the base of the cutting edge forming piece is 1.1mm to 2.8mm, and the thickness of the base of the cutting edge is 0.2mm to 1.3mm.

In one embodiment, the manufacturing method is to attach the cutting edge to the body by adhesion.

In another embodiment, the manufacturing method is to attach the cutting edge to the body by embedding an embedded portion provided in the body. In such a manufacturing method, the cutting edge is fixed to the embedded portion by vacuum brazing in a state where the cutting edge is embedded in the embedded portion.

In one embodiment, the cutting of the base portion of the cutting edge forming piece includes grinding.

Effects of the invention

According to the present invention, in the method for manufacturing an end mill in which a cutting edge having a base portion and a sintered diamond layer is attached to a body, a cutting edge forming piece is cut from a base material having a thick base portion, and the base portion of the cutting edge forming piece is cut to reduce the thickness of the base portion, thereby obtaining a cutting edge, whereby it is possible to realize a method for manufacturing an end mill in which the warping of the cutting edge is suppressed and the cutting edge is attached to the body satisfactorily. As a result, an end mill excellent in cutting ability, strength, and durability can be manufactured. According to the present invention, the thick base portion is cut thinner, which increases the material cost, but the manufacturing efficiency as a whole is excellent if considering the mountability of the cutting edge to the main body, the strength and durability as a result thereof, and the like. That is, the present invention solves the problem by means which are never adopted in the technical common knowledge in the industry.

Drawings

Fig. 1 (a) is a schematic cross-sectional view illustrating an example of a base material of a cutting edge used in the manufacturing method according to the embodiment of the present invention; fig. 1 (b) is a perspective view of the base material of fig. 1 (a).

Fig. 2 (a) is a schematic plan view illustrating a cutting edge formation piece cut from a base material in the manufacturing method according to the embodiment of the present invention; fig. 2 (b) is a perspective view of the cut cutting edge forming sheet of fig. 1 (a).

Fig. 3 is a schematic cross-sectional view illustrating the production of a cutting edge in the production method according to the embodiment of the present invention.

Fig. 4 (a) is a schematic plan view illustrating an example of attaching a cutting edge to a body in the manufacturing method according to the embodiment of the present invention; fig. 4 (b) is a schematic plan view illustrating another example.

Fig. 5 (a) is a schematic plan view illustrating an example of the end mill obtained by the embodiment of fig. 4 (b); fig. 5 (b) is a perspective view of the end mill of fig. 5 (a).

Fig. 6 is a schematic plan view showing an example of the shape of a nonlinear processed optical film obtained by the method for producing an optical film using an end mill obtained by the method for producing an optical film according to the present invention.

Fig. 7 is a schematic perspective view for explaining cutting processing of an optical film using an end mill obtained by the manufacturing method of the present invention.

Fig. 8 (a) to 8 (e) are schematic plan views illustrating a series of steps of non-linear cutting processing, which is an example of cutting processing of an optical film of an end mill obtained by the manufacturing method of the present invention.

Detailed Description

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. Further, the drawings are schematically shown for the sake of easy observation, and ratios of length, width, thickness, etc., and angles, etc., in the drawings are different from actual ones.

A. Method for manufacturing end mill

The method for manufacturing the end mill of the invention comprises the following steps: cutting a cutting edge forming piece of a predetermined shape from a base material having a base portion made of a superhard material and a sintered diamond layer provided on one surface of the base portion by electric discharge machining or laser machining; cutting the base of the cutting edge forming piece to reduce the thickness of the base, thereby obtaining a cutting edge; and attaching the cutting edge to the body. The respective steps will be described in order below.

B. Base material

First, a base material is prepared. Fig. 1 (a) is a schematic cross-sectional view illustrating an example of a base material of a cutting edge used in the manufacturing method according to the embodiment of the present invention; fig. 1 (b) is a perspective view of the base material of fig. 1 (a). As described above, the base material 10 has the base portion 12 made of the superhard material and the sintered diamond layer 14 provided on one surface of the base portion 12. The base material 10 may have any suitable shape. For example, the base material 10 may be disk-shaped (circular in plan view) as shown in the illustrated example.

As the superhard material constituting the base 12, a typical example is a super hard alloy. Cemented carbide typically refers to a composite material obtained by sintering carbide of a metal of group IVa, va, VIa of the periodic table with an iron-based metal such as Fe, co, ni, or the like. Specific examples of the cemented carbide include: WC-Co-based alloy, WC-TiC-Co-based alloy, WC-TaC-Co-based alloy, WC-TiC-TaC-Co-based alloy, WC-Ni-Cr-based alloy. The sintered diamond constituting the sintered diamond layer 14 is typically polycrystalline diamond obtained by sintering small particles of diamond together with a binder (e.g., metal powder, ceramic powder) at high temperature and high pressure. The characteristics of the sintered diamond can be adjusted by changing the kind of the binder, the mixing ratio, and the like.

The thickness of the base material 10 is, for example, 1.6mm to 3.2mm, preferably 1.6mm to 2.4mm. When the thickness of the base material is in such a range, warpage of the cutting edge forming piece can be suppressed when the cutting edge forming piece is cut from the base material, and thus warpage of the obtained cutting edge can be suppressed. As a result, the cutting edge can be favorably attached to the end mill body.

The thickness of the base 12 is, for example, 1.1mm to 2.8mm. When the thickness of the base portion is in such a range, the warpage of the cutting edge forming piece can be suppressed when the cutting edge forming piece is cut out of the base material, as in the above, whereby the warpage of the obtained cutting edge can be suppressed. As a result, the cutting edge can be favorably attached to the end mill body. The thickness of the sintered diamond layer 14 is, for example, 0.2mm to 2.8mm, preferably 0.2mm to 1.0mm, and more preferably 0.3mm to 0.8mm.

The base material 10 can be produced by a method known in the art.

B. cutting of cutting edge forming pieces

Next, as shown in fig. 2 (a), a cutting edge forming piece 20 is cut from the base material 10. The cutting of the cutting edge forming piece is performed by electric discharge machining or laser machining. The electric discharge machining is not particularly limited, and for example, wire electric discharge machining by engraving can be used. Wire electric discharge machining is performed, for example, by the following steps: the metal wire is used as an electrode, and the base material is immersed in the processing liquid to cause discharge between the base material and the electrode, thereby melting and removing the base material. The engraving electric discharge machining is performed, for example, by the following steps: a graphite (graphite) electrode, a copper electrode, or the like, which is formed in a shape corresponding to the shape desired to be formed on the base material, is brought close to the base material. The laser processing is performed by the following steps: cutting the base material by laser. As shown in fig. 2 (b), the cut cutting edge forming piece 20 has the same base portion 12 and sintered diamond layer 14 as the base material. The thickness of the cutting edge forming piece, the thickness of the base portion, and the thickness of the sintered diamond layer are as described in item a above in relation to the base material.

The cutting edge forming blade 20 typically has a rectangular top view shape as shown in fig. 2 (b). By having such a shape, a cutting edge having a desired shape can be produced by cutting the base as described later. The length L of the cutting edge forming blade 20 may correspond to the length of the resulting cutting edge. By cutting the cutting edge forming piece from the base material as described above, the cutting edge forming piece (eventually the cutting edge) can be made into a seamless integrated body in the longitudinal direction. As a result, a cutting edge (ultimately, an end mill) excellent in all of cutting ability, strength and durability can be produced. The length L of the cutting edge forming blade 20 is preferably 15mm or more, more preferably 20mm to 50mm. In the case of cutting the optical film using the obtained end mill, the workpiece having a desired number of optical films stacked thereon can be cut, and therefore the efficiency of the cutting process can be improved.

C. manufacture of cutting edge (cutting of base)

Next, as shown in fig. 3, the base 12 of the cutting edge forming blade 20 is cut to reduce its thickness, thereby obtaining the cutting edge 30. That is, the thickness of the cutting edge 30 is smaller than the thickness of the base material 10 (the thickness of the cutting edge forming piece 20). Cutting typically may be performed by grinding. The grinding is performed by grinding the surface of the base 12 with a flat grinder. The cutting is not limited to grinding, and may be performed by other methods. For example, milling, lathe, wire cutting, or the like may be used.

The resulting cutting edge 30 has a cut base 16 (hereinafter simply referred to as base 16 or base 16 of the cutting edge) and a sintered diamond layer 14. The thickness of the cutting edge 30 is, for example, 0.7mm to 1.6mm, preferably 0.75mm to 1.2mm. The thickness of the base 16 of the cutting edge 30 is, for example, 0.2mm to 1.3mm, preferably 0.4mm to 0.9mm. The thickness of the base portion 16 of the cutting edge 30 is smaller than the thickness of the base portion 12 of the base material 10 (the thickness of the base portion 12 of the cutting edge forming blade 20). The ratio d ₁₄/d₁₆ of the thickness of the sintered diamond layer 14 to the base 16 of the cutting edge 30 is preferably 70% to 400%, more preferably 100% to 300%. When the ratio d ₁₄/d₁₆ is in such a range, it is advantageous to suppress warpage at the time of brazing and strength as a tool can be ensured.

D. Mounting cutting edge to main body (manufacture of end mill)

Next, as shown in fig. 4 (a) or 4 (b), the obtained cutting edge 30 is attached to the end mill body 40. The main body 40 can be manufactured as follows: the sintered body obtained by the powder metallurgy method known in the art is processed into a predetermined shape (for example, a cylindrical shape) by a method known in the art.

In one embodiment, as shown in fig. 4 (a), the cutting edge 30 is mounted to the body 40 by attachment. In the present invention, since warpage of the cutting edge is suppressed, such attachment becomes possible. In the present embodiment, the mounting surface 42 is formed on the main body 40. The mounting surface 42 may be formed on the body 40 by any suitable method (e.g., cutting). Attachment is typically performed by brazing (e.g., vacuum brazing or high frequency brazing).

In another embodiment, as shown in fig. 4 (b), the cutting edge 30 is attached to the main body 40 by being embedded in an embedded portion 44 provided to the main body 40 (typically, the cutting edge 30 is inserted into the embedded portion 44). In the present invention, since warpage of the cutting edge is suppressed, such embedding is possible. Further, in the case of the configuration shown in fig. 4 (b), the cutting ability, strength, and durability can be improved. The buried portion 44 may be formed by any suitable method. Specific examples of the forming method include laser processing and cutting processing. The depth of the embedded portion 44 is preferably 0.30mm to 1.50mm, more preferably 0.30mm to 1.00mm, and even more preferably 0.30mm to 0.70mm. When the depth of the embedded portion is within such a range, both the fixation strength of the cutting edge to the body and the strength of the body itself can be ensured. The cutting edge 30 is preferably fixed to the embedded portion 44 by vacuum brazing in a state of being embedded in the embedded portion 44. In the case of such a configuration, the cutting ability, strength, and durability can be further improved. Even a cutting edge including a sintered diamond layer can be satisfactorily fixed to a body (embedded portion) by vacuum brazing. This is because residual oxygen and moisture during brazing can be removed, and therefore, the oxide film on the main body surface can be broken and regeneration of the oxide film can be prevented, whereby wettability of the main body surface can be increased.

In the example shown in the figure, the embodiment has been described in which the number of cutting edges is two, but the number of cutting edges may be one, or three or more (for example, three or four). The number of cutting edges is preferably two to three. In the case of such a configuration, since the distance between the cutting edges is appropriately ensured, chips can be discharged more satisfactorily. More preferably the number of cutting edges is two. With such a configuration, the rigidity of the cutting edge can be ensured, and the notch (pocket) can be ensured, so that chips can be discharged satisfactorily.

In the example of the figures, the embodiment in which the cutting edge is flat has been described, but the cutting edge may be sharp (for example, in fig. 4 (a) and 4 (b), the tip may have an acute angle in a plan view). The tip may be sharpened by any suitable cutting process.

As described above, an end mill can be manufactured.

E. End mill

Fig. 5 (a) is a schematic plan view illustrating an example of the end mill obtained by the embodiment of fig. 4 (b), and fig. 5 (b) is a schematic perspective view of the end mill of fig. 5 (a). The end mill 100 shown in the drawing includes a main body 40 and a cutting edge 30, the main body 40 rotates around a rotation axis 46 extending in a vertical direction (a lamination direction of workpieces, which are objects to be cut formed by laminating optical films, which will be described later in detail), and the cutting edge 30 protrudes from the main body 40 to have an outermost diameter. The end mill is typically an upright mill. In the example shown in the drawing, the body 40 is provided with an embedded portion 44, and the cutting edge 30 is fixed to the body 40 by embedding the embedded portion 44. In the case of such a configuration, even if the end mill has a small diameter and it is difficult to sufficiently secure the mounting surface of the cutting edge on the surface of the main body, the cutting edge can be satisfactorily mounted on the main body. Therefore, it is possible to practically manufacture a small-diameter end mill having practically acceptable cutting ability. Further, an end mill excellent in strength and durability can be realized. When a plurality of embedded portions are provided, the embedded portions are preferably provided at positions symmetrical to the rotation axis 46. With such a configuration, excellent cutting can be achieved and the strength and durability of the end mill can be further improved.

The helix angle of the cutting edge 30 of the end mill of the example of the figure is typically 0. In the case of such a configuration, cutting of an optical film described later can be performed satisfactorily. More specifically, when cutting (for example, profile machining or non-linear machining) is performed using a cutting edge having a helix angle, the cutting surface may be tapered when viewed in the lateral direction, and in this case, the cutting surface may be suppressed from being tapered by using a cutting edge having a helix angle of 0 °. Here, the irregular processing means, for example, processing the optical film into a shape other than a rectangle. In particular, when a small-diameter end mill is used to perform fine non-linear processing (profile processing) on an optical film, a significant effect can be obtained. In the present specification, the term "helix angle of 0 °" means that the cutting edge 30 extends in a direction substantially parallel to the rotation axis 46; in other words, it means that the blade is not helical with respect to the axis of rotation. The term "0 ° means substantially 0 °, and includes a case where a spiral is slightly angled due to a machining error or the like.

The outer diameter of the end mill illustrated in the figures is typically less than 10mm, preferably 3mm to 9mm, more preferably 4mm to 7mm. According to the embodiment of the present invention, an end mill having such a small outer diameter and having practically acceptable cutting ability can be practically manufactured. As a result, for example, in the case of fine non-linear processing (profile processing) of an optical film using such a small-diameter end mill, cracks and a yellow band of the optical film can be favorably suppressed, and in the case of an optical film having an adhesive layer, the shortage of adhesive can be favorably suppressed. In the present specification, the "outer diameter of the end mill" refers to a value obtained by multiplying the distance from the rotation shaft 46 to the cutting edge 30a by 2.

The cutting edge 30 typically includes a cutting edge 30a, a rake surface 30b, and a relief surface 30c. The rake face 30b is located on the downstream side in the rotation direction R, and the recess 50 can be defined by the rake face 30b and the main body 40. The surface of the sintered diamond layer 14 corresponds to the rake face 30b and the surface of the base 16 corresponds to the relief face 30c, the relief face 30c (base 16) preferably being roughened. As the roughening treatment, any suitable treatment may be employed. As a representative example, sand blasting may be cited. By roughening the relief surface, adhesion of an adhesive or a pressure-sensitive adhesive to the cutting edge can be suppressed when the optical film is cut and the optical film includes a pressure-sensitive adhesive layer (e.g., an adhesive layer or a pressure-sensitive adhesive layer), and as a result, blocking can be suppressed. In the present specification, "blocking" refers to a phenomenon in which optical films in a work are bonded to each other by an adhesive or an adhesive agent at end surfaces in the case where the optical films include an adhesive layer, and the adhesion of the optical films to each other is promoted by chips of the adhesive or the adhesive agent attached to the end surfaces.

F. Method for using end mill

The end mill obtained by the production method of the present invention is typically applicable to a production method of an optical film. The manufacturing method preferably includes cutting an end face of the optical film.

Specific examples of the optical film include: a polarizer, a retardation film, a polarizing plate (typically, a laminate of a polarizer and a protective film), a conductive film for a touch panel, a surface-treated film, and a laminate of these laminated appropriately according to the purpose (for example, an antireflection circular polarizing plate, a polarizing plate with a conductive layer for a touch panel). In one embodiment, the optical film includes an adhesive layer (e.g., an adhesive layer). By using the end mill according to the embodiment of the present invention, even in the case of an optical film including an adhesive layer, it is possible to suppress the lack of adhesive in cutting.

Hereinafter, a method for producing a polarizing plate with an adhesive layer, which is an example of an optical film, will be described. Specifically, each step in the method for producing the pressure-sensitive adhesive layer-attached polarizing plate in a plan view as shown in fig. 6 will be described. Further, the optical film is not limited to the adhesive layer-attached polarizing plate and the top view shape of the adhesive layer-attached polarizing plate is not limited to the top view shape of fig. 6, as will be apparent to those skilled in the art. That is, the end mill obtained by the production method of the present invention can be applied to any production method of an optical film having any shape.

F-1 formation of the workpiece

Fig. 7 is a schematic perspective view for explaining cutting processing of an optical film, which shows a workpiece 200. As shown in fig. 7, a work 200 is formed by stacking a plurality of optical films (polarizing plates with adhesive layers). Since the polarizing plate with the adhesive layer can be manufactured by a conventional method known in the art, a detailed description of the manufacturing method is omitted. The adhesive layer-carrying polarizer may typically be cut into any suitable shape when forming the workpiece. Specifically, the polarizing plate with the adhesive layer may be cut into a rectangular shape, may be cut into a shape similar to a rectangular shape, and may be cut into a shape (e.g., circular shape) suitable for the purpose. In the example shown in the figure, the polarizing plate with the adhesive layer is cut into a rectangular shape, and the work 200 has outer peripheral surfaces (cut surfaces) 200a and 200b facing each other and outer peripheral surfaces (cut surfaces) 200c and 200d orthogonal to them. The workpiece 200 is preferably held up and down by a holding mechanism (not shown). The total thickness of the work piece is preferably 10mm to 50mm, more preferably 15mm to 25mm, still more preferably about 20mm. In the case of such a thickness, damage due to impact at the time of pressing or cutting processing by the clamping mechanism can be prevented. The polarizing plates with the adhesive layer are overlapped in such a manner that the work becomes such a total thickness. The number of sheets of the adhesive layer-attached polarizing plate constituting the work may be, for example, 20 to 100 sheets. The clamping mechanism (e.g., the clamp) may be composed of a soft material or a hard material. In the case of being composed of a soft material, the hardness (JIS A) thereof is preferably 60 DEG to 80 deg. In the case of excessively high hardness, an indentation caused by the holding mechanism may remain. If the hardness is too low, the cutting accuracy may become insufficient due to positional displacement caused by deformation of the jig.

F-2 end mill machining

Next, a predetermined position of the outer peripheral surface of the workpiece 200 is cut by the end mill 100. The end mill 100 is typically used in the following manner: held by a machine tool (not shown), rotated at a high speed about the rotation axis of the end mill, and fed in a direction intersecting the rotation axis while bringing the cutting edge into contact with the outer peripheral surface of the workpiece 200 and cutting into the workpiece. That is, the cutting is typically performed by bringing a cutting edge of the end mill into contact with the outer peripheral surface of the workpiece 200 and cutting into the same. In manufacturing the polarizing plate with the adhesive layer in a planar shape as shown in fig. 6, chamfer portions 200E, 200F, 200G, 200H are formed at four corners of the outer periphery of the work 200, and a concave portion 200I is formed at the center portion of the outer peripheral surface connecting the chamfer portions 200E and 200H.

The cutting process of the workpiece 200 will be described in detail. First, as shown in fig. 8 (a), chamfering is performed on the portion of fig. 6 where the chamfer portion 200E is formed; next, as shown in fig. 8 (b) to 8 (d), chamfering is sequentially performed on the portions where the chamfer portions 200F, 200G, and 200H are formed. Finally, as shown in fig. 8 (e), the recess 200I is cut. In the example of the drawing, the chamfer portions 200E, 200F, 200G, and 200H and the recess portion 200I are formed in the above-described order, but these may be formed in any appropriate order.

The cutting conditions can be appropriately set according to the structure of the pressure-sensitive adhesive layer-attached polarizing plate, a desired shape, and the like. For example, the rotation speed (rotation number) of the end mill is preferably less than 25000rpm, more preferably not more than 22000rpm, and still more preferably not more than 20000 rpm. The lower limit of the rotational speed of the end mill may be 10000rpm, for example. For another example, the feed rate of the end mill is preferably 500 to 10000 mm/min, more preferably 500 to 2500 mm/min, and still more preferably 800 to 1500 mm/min. For another example, the cutting amount of the end mill is preferably 0.8mm or less, and more preferably 0.3mm or less. The number of cuts at the cutting site of the end mill may be one cut, two cuts, three cuts or more.

As described above, using the end mill obtained by the manufacturing method of the present invention, a polarizing plate with an adhesive layer that has been cut can be obtained. In the example of the figure, a polarizing plate with an adhesive layer including a non-linearly processed portion can be obtained.

Industrial applicability

The end mill obtained by the manufacturing method of the present invention can be suitably used for cutting an optical film. The optical film cut by the end mill of the present invention can be used for a special-shaped image display portion typified by, for example, an instrument panel of an automobile or an intelligent watch.

Symbol description

10 Base material

12 Base of cutting edge forming piece

14 Sintered diamond layer

16 Base of cutting edge

20 Cutting edge forming blade

30 Cutting edge

30A tip

30B rake face

30C yielding surface

40 Main body

42 Mounting face

44 Embedded part

46 Rotation shaft

50 Notch

100 End mill

200 Work piece

Claims

1. A method for manufacturing an end mill, comprising the steps of:

cutting a cutting edge forming piece of a predetermined shape from a base material having a base portion made of a superhard material and a sintered diamond layer provided on one surface of the base portion by electric discharge machining or laser machining;

cutting the base of the cutting edge forming piece to reduce the thickness of the base, thereby obtaining a cutting edge; and

The cutting edge is mounted to the body,

The thickness of the cutting edge forming piece is 1.6 mm-3.2 mm, and the thickness of the cutting edge obtained by cutting the base of the cutting edge forming piece is 0.7 mm-1.2 mm.

2. The method of manufacturing an end mill according to claim 1, wherein the cutting edge is mounted to the body by attachment.

3. The method of manufacturing an end mill according to claim 1, wherein the cutting edge is attached to the body by being embedded in an embedded portion provided in the body.

4. The method of manufacturing an end mill according to claim 3, wherein the cutting edge is fixed to the embedded portion by vacuum brazing in a state in which the cutting edge is embedded in the embedded portion.

5. The method of manufacturing an end mill according to any one of claims 1 to 4, wherein cutting of the base of the cutting edge forming piece includes grinding.