JP2022132448A - End mill and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an end mill which, while having a small diameter, has a plurality of cutting blades satisfactorily attached to a body and is excellent in strength and durability and to provide a simple manufacturing method therefor.

SOLUTION: An end mill according to an embodiment of the present invention includes: a body which is provided with a plurality of embedding portions and rotates about a rotation axis; and a plurality of cutting blades which are embedded and fixed in the plurality of embedding portions and configured as outermost diameters. In this end mill, each cutting blade contains sintered diamond, a twist angle of the cutting blade is 0° and the outer diameter is less than 10 mm. Each cutting blade is embedded and fixed in the embedding portion such that an extension of the cutting blade does not pass through the rotation axis and defines a rake angle of a predetermined angle. A reference surface extending in a direction forming a predetermined angle relative to the extending direction of the cutting blade is formed in the body.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to an end mill and its manufacturing method.

An end mill is widely known as one of cutting tools. An end mill typically has a body that rotates about an axis of rotation and a cutting edge attached to the surface of the body.

JP 2016-182658 A

Although there are many materials for cutting blades of end mills, the present inventors considered using sintered diamond blades as a countermeasure against abrasion of cutting blades. Ordinary end mills are formed by shaving a single piece of metal to form a blade, but sintered diamond blades are difficult to form by shaving, and must be attached separately to the body of the end mill. An end mill may be required to have a small diameter (for example, an outer diameter of less than 10 mm) depending on the application. In such a small-diameter end mill, it is often difficult to secure a mounting surface for mounting the cutting blade on the main body, and it is often difficult to mount the cutting blade on the main body. Furthermore, when multiple cutting blades are used, it is often more difficult to attach the cutting blades to the body and ensure strength and durability.

The present invention has been made to solve the above-mentioned conventional problems, and its main purpose is to provide an end mill and end mill having excellent strength and durability in which a plurality of cutting blades are satisfactorily attached to the main body while having a small diameter. It is to provide a simple manufacturing method thereof.

The end mill of the present invention comprises a main body provided with a plurality of embedding portions and rotating around a rotation axis; and a plurality of cutting blades configured as outermost diameters embedded in and fixed to the plurality of embedding portions, respectively. and; The cutting edge comprises sintered diamond, the cutting edge has a helix angle of 0° and an outer diameter of less than 10 mm. The cutting blade is embedded and fixed to the embedded portion so that the extension line of the cutting blade does not pass through the rotating shaft.
In one embodiment, the cutting blade is embedded and fixed to the embedded portion so as to define a rake angle of a predetermined angle.
In one embodiment, the main body is formed with a reference surface extending in a direction forming the predetermined angle with respect to the extending direction of the cutting blade.
In one embodiment, the main body is formed with an embedded surface extending in a direction crossing the extending direction of the reference surface.
In one embodiment, the main body is formed with an embedded surface extending in a direction forming the predetermined angle with respect to a direction perpendicular to the extending direction of the reference surface.
In one embodiment, the cutting blade is embedded in and fixed to the embedding portion so as to be orthogonal to the embedding surface.
In one embodiment, in the main body, a rotational direction upstream side of the embedded portion when viewed from the rotation axis direction protrudes from a rotational direction downstream side of the embedded portion.
In one embodiment, the cutting blade has a base made of superhard material and a sintered diamond layer provided on one surface of the base.
In one embodiment, the embedded portion has a depth of 0.30 mm to 1.50 mm.
In one embodiment, the plurality of embedded portions are provided at symmetrical positions with respect to the rotation axis.
According to another aspect of the present invention, a method for manufacturing the end mill can be provided. This manufacturing method includes embedding the cutting blade in the embedding portion of the main body; adhering;
In one embodiment, the cutting blade has a base made of a superhard material and a sintered diamond layer provided on one surface of the base, and the manufacturing method includes the base and Both of the sintered diamond layers are attached to the embedment by vacuum brazing.
In another embodiment, the cutting blade is made of sintered diamond, and the manufacturing method fixes the sintered diamond to the embedded portion by vacuum brazing.

According to the present invention, in a small-diameter end mill, by providing an embedded portion in the main body and embedding and fixing the cutting blade in the embedded portion, the cutting blade is well attached to the main body, resulting in excellent strength and durability. end mill can be realized. Furthermore, the strength and durability can be further improved by embedding and fixing the cutting blade in the embedding portion so that the extended line of the cutting blade does not pass through the rotating shaft. As a result, even when a plurality of cutting edges are used, an excellent end mill as described above can be realized.

FIG. 1(a) is a schematic plan view seen from the axial direction for explaining the structure of an end mill according to one embodiment of the present invention; FIG. 1(b) is a schematic of the end mill of FIG. 1(a); It is a perspective view. 2(a) to 2(e) are schematic plan views viewed from the axial direction for explaining the structure of an end mill according to another embodiment of the present invention. 1 is a schematic plan view showing an example of the shape of a non-linearly processed optical film obtained by a method of manufacturing an optical film using an end mill according to an embodiment of the present invention; FIG. FIG. 4 is a schematic perspective view for explaining cutting of an optical film using an end mill according to an embodiment of the present invention; FIGS. 5(a) to 5(e) are schematic plan views illustrating a series of steps of non-linear cutting, which is an example of cutting an optical film using an end mill according to an embodiment of the present invention. .

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

A. End Mill FIG. 1(a) is a schematic plan view seen from the axial direction for explaining the structure of an end mill according to one embodiment of the present invention; FIG. 1(b) is the end mill of FIG. It is a schematic perspective view. The illustrated end mill 100 includes a main body 20 that rotates about a rotating shaft 22 that extends in the vertical direction (the direction in which the work is laminated; the work is an object to be cut in which optical films are laminated; the details will be described later); and a cutting edge 10 configured as the outermost diameter protruding from. The end mill is typically a straight end mill. In the embodiment of the present invention, the main body 20 is provided with an embedded portion 24 , and the cutting blade 10 is embedded in the embedded portion 24 and fixed to the main body 20 . With such a configuration, even if the end mill has a small diameter and it is difficult to secure a sufficient mounting surface for the cutting blade on the surface of the main body, the cutting blade can be satisfactorily mounted on the main body. Therefore, it is possible to actually produce a small diameter end mill having a practically acceptable cutting capacity. Furthermore, an end mill having excellent strength and durability can be realized. In the embodiment of the present invention, the main body 20 is provided with a plurality of embedded portions 24, and the cutting blades 10 are embedded and fixed to the plurality of embedded portions 24, respectively. Although two embedded portions 24, 24 are provided in the illustrated example, three or more embedded portions may be provided. That is, the number of cutting blades may be two, or three or more. Furthermore, in the embodiment of the present invention, in addition to the above configuration, the cutting blade 10 is embedded and fixed in the embedded portion 24 so that the extension line of the cutting blade 10 does not pass through the rotating shaft 22 . With such a configuration, the distance between the embedded parts (substantially, the distance between the deep parts of the embedded parts) is greater than the configuration in which the embedded parts are formed so that the extension line of the cutting blade passes through the rotation axis. can be increased. As a result, the strength and durability of the main body 20 can be further improved, and finally the strength and durability of the end mill can be further improved. As a result, even when a plurality of cutting edges are used, an excellent end mill as described above can be realized. In this specification, the term "extension line of the cutting edge" refers to a line extending in the length direction of the cutting edge at the midpoint in the thickness direction of the cutting edge (line E in FIG. 1(a)).

A plurality of embedding portions 24 are provided as described above, and the number of cutting blades 10 can be set according to the number of embedding portions 24 . The embedded portions are preferably provided at 2 to 4 locations, more preferably 2 to 3 locations. That is, the number of cutting edges of the end mill is preferably 2-4, more preferably 2-3. With such a configuration, an appropriate interval between the cutting blades is ensured, so that cutting waste can be discharged satisfactorily. More preferably, the number of blades is two. With such a configuration, the rigidity of the cutting blade is secured, and pockets are secured, so that cutting waste can be discharged satisfactorily. The plurality of embedded portions are preferably provided at symmetrical positions with respect to the rotation axis 22 . With such a configuration, good cutting can be achieved, and the strength and durability of the end mill can be further improved. When the end mill has two cutting blades, for example, they are arranged at approximately 180 degrees apart in the circumferential direction of the body of the end mill. When the end mill has three cutting edges, for example, they are arranged at intervals of approximately 120° in the circumferential direction of the end mill body.

In the illustrated example, the depth d of the embedded portion 24 is preferably 0.30 mm to 1.50 mm, more preferably 0.30 mm to 1.00 mm, still more preferably 0.30 mm to 0.70 mm. be. If the depth of the embedded portion is within this range, it is possible to secure both the fixing strength of the cutting blade to the main body and the strength of the main body itself. If the embedded portion has a depth of less than 0.30 mm, the cutting blade may have insufficient bonding strength to the main body. If the depth of the embedded portion exceeds less than 1.50 mm, the strength of the main body itself may be insufficient.

In an embodiment of the invention, the helix angle of the cutting edge 10 is 0°. With such a configuration, it is possible to satisfactorily cut the optical film, which will be described later. More specifically, when cutting using a cutting blade having a helix angle (for example, irregular machining or non-linear machining), the cut surface may be tapered when viewed from the lateral direction, but the helix angle is 0 °. By using a cutting edge, it is possible to prevent the cut surface from becoming tapered. Here, irregular shape processing means processing an optical film into a shape other than a rectangle, for example. In particular, a remarkable effect can be obtained when an optical film is subjected to fine non-linear processing (irregular shape processing) using a small-diameter end mill. In this specification, "the twist angle is 0°" means that the cutting blade 10 extends in a direction substantially parallel to the rotation axis 22, in other words, the blade is not twisted with respect to the rotation axis. Say. It should be noted that "0°" means substantially 0°, and includes the case where there is a slight angle twist due to processing error or the like.

In an embodiment of the invention, the outer diameter of the end mill is less than 10 mm, preferably between 3 mm and 9 mm, more preferably between 4 mm and 7 mm. According to an embodiment of the present invention, an end mill having such a small outside diameter and having a practically acceptable cutting ability can actually be made. As a result, for example, in fine non-linear processing (irregular shape processing) using such a small-diameter end mill, cracks and yellow bands in the optical film can be suppressed satisfactorily. It is possible to satisfactorily suppress adhesive chipping. In this specification, the term "outer diameter of the end mill" refers to the distance from the rotary shaft 22 to the cutting edge 10a doubled.

The cutting blade 10 typically includes a cutting edge 10a, a rake face 10b and a relief face 10c. A pocket 30 may be defined by the rake face 10b and the body 20 . The cutting edge 10a may be sharp as in the illustrated example (for example, may have an acute apex in plan view) or may be flat. The plan view shape of the relief surface 10c may be linear as shown in the figure, may be curved (may have two relief surfaces), or may be a smooth curve. good too. The relief surface 10c is preferably roughened. Any appropriate treatment can be adopted as the roughening treatment. A typical example is blasting. By roughening the relief surface, when the optical film is cut and the optical film contains an adhesive layer (e.g., an adhesive layer, a pressure-sensitive adhesive layer), an adhesive or adhesive to the cutting blade Adhesion of the adhesive is suppressed, and as a result, blocking can be suppressed. As used herein, the term “blocking” refers to a phenomenon in which optical films on a workpiece adhere to each other with an adhesive or pressure-sensitive adhesive on the end surfaces when the optical film includes an adhesive layer. The residue contributes to adhesion between the optical films.

The cutting blade 10 may be embedded and fixed in the embedding portion 24 so as to define a predetermined rake angle α as shown in the figure, and the rake angle is 0° (the direction in which the cutting blade extends and the direction of the main body). It may be embedded and fixed in the embedding portion 24 so that it is parallel to the diameter direction. When the rake angle is specified as in the illustrated example, the rake angle α is preferably 5° to 45°, more preferably 5° to 30°. If the rake angle α is in such a range, the sharpness of the blade can be ensured, the resistance during cutting can be appropriately suppressed, and the pocket 30 can be appropriately sized to discharge cutting debris satisfactorily. can. As a result, cracks and yellow bands in the optical film can be effectively suppressed when the optical film is cut, and adhesive chipping can be effectively suppressed when the optical film has an adhesive layer. If the rake angle α is too large, it may become difficult to attach the cutting edge to the main body. The clearance angle β of the cutting edge 10 is preferably 5° to 30°, more preferably 5° to 25°. If the relief angle β is within such a range, contact between the relief surface 10c and the workpiece 200 can be prevented, and resistance during cutting can be appropriately suppressed. Furthermore, it is possible to prevent the edge angle γ from becoming excessively small. As a result, cracks and yellow bands in the optical film can be effectively suppressed when the optical film is cut, and adhesive chipping can be effectively suppressed when the optical film has an adhesive layer. Additionally, the life of the cutting edge can be increased. The included angle γ of the cutting edge 10 is preferably 45° or more, more preferably 55° or more. If the included angle γ is within such a range, the life of the cutting edge can be increased. Considering the rake angle α and the clearance angle β, the cutting edge angle γ is less than 85°, preferably 80° or less, more preferably 75° or less. In this specification, the “rake angle α” is the angle formed by the straight line connecting the cutting edge 10a and the rotary shaft 22 and the rake face 10b; The “cutting edge angle γ” is an angle defined with the cutting edge 10a as the apex, and is an angle calculated from the formula: 90°−rake angle α−clearance angle β.

In an embodiment of the present invention, cutting edge 10 comprises sintered diamond. With such a configuration, it is possible to satisfactorily perform fine non-linear processing (irregular shape processing) using a small-diameter end mill as described above. More specifically, the cutting blade 10 may be made of sintered diamond (substantially made of sintered diamond), or may be made of sintered diamond as shown in the figure. good too. In the illustrated example, the cutting blade 10 has a base portion 11 and a sintered diamond layer 12 provided on one surface of the base portion 11 (the surface on the downstream side in the rotational direction R of the end mill). The surface of the sintered diamond layer 12 becomes the rake face 10b of the cutting edge. With the configuration of the illustrated example, it is easy to process and cut out the cutting blade. Furthermore, in the illustrated example, the effect of providing the embedded portion is remarkable. Details are as follows. When attaching such a laminated structure cutting blade to the main body, the attachment is typically performed by brazing. As a result, the cutting blade is often warped during attachment by brazing, making it difficult to attach the cutting blade to the main body. According to the embodiment of the present invention, since the cutting blade is fixed in the embedding portion of the main body in a state of being embedded, it is possible to attach the cutting blade even when the cutting blade is warped.

In the illustrated example, the thickness of the base 11 can be, for example, 0.2 mm to 2.0 mm. As a cemented carbide material forming the base portion 11, a cemented carbide alloy is typically used. Cemented carbide typically refers to composite materials obtained by sintering carbides of IVa, Va, and VIa group metals of the periodic table with iron-based metals such as Fe, Co, and Ni. Specific examples of cemented carbide include WC-Co alloys, WC-TiC-Co alloys, WC-TaC-Co alloys, WC-TiC-TaC-Co alloys, WC-Ni alloys, WC-Ni -Cr alloys can be mentioned. The thickness of the sintered diamond layer 12 can be, for example, 0.5 mm to 1.5 mm. The sintered diamond forming the sintered diamond layer 12 is typically a polycrystalline diamond obtained by baking small diamond grains together with a binder (for example, metal powder or ceramic powder) at high temperature and high pressure. The characteristics of the sintered diamond can be adjusted by changing the type of binder, the blending ratio, and the like.

The cutting blade 10 is preferably a one-piece body that is seamless along the length of the main body 20 (rotation axis direction). The cutting ability, strength and durability can be further improved by having the cutting blade be a seamless, one-piece piece. The length of the cutting edge in the rotation axis direction is preferably 15 mm or more, more preferably 20 mm to 50 mm. With such a length, when cutting an optical film, it is possible to cut a workpiece in which a desired number of optical films are laminated, so that the efficiency of cutting can be improved.

Several representative examples of modifications of the present invention will be described below.

FIG. 2(a) is a schematic plan view seen from the axial direction for explaining the structure of an end mill according to another embodiment of the present invention. The illustrated end mill 101 has a body 20 on which a reference surface 26 is formed. The reference plane 20 extends in a direction forming the predetermined angle (the rake angle α) with respect to the extending direction of the cutting edge 10 . In other words, the reference plane 20 extends in a direction substantially parallel to the straight line connecting the cutting edge 10a and the rotating shaft 22. As shown in FIG. By forming the reference plane 26, the direction of the embedded portion 24 can be easily set with reference to the reference plane 26, and as a result, the rake angle of the cutting edge can be easily set. In addition, in FIG. 2A, the reference surface 26 is formed on two side surfaces of the main body 20, but the reference surface 26 may be formed only on one side surface.

2(b) and 2(c) are schematic plan views viewed from the axial direction for explaining the structure of an end mill according to still another embodiment of the present invention. Each of the illustrated end mills 102 and 103 further includes an embedded surface 28 formed in the body 20 . The embedded surface 28 is a flat surface, and the embedded portion 24 is formed on the flat surface. The embedding surface 28 is typically formed in a direction intersecting the extending direction of the reference plane. The embedded surface 28 may be formed, for example, so as to extend in a direction perpendicular to the extending direction of the reference surface as shown in FIG. 2(b); may be formed so as to extend in a direction forming the above-mentioned predetermined angle (the angle of the rake angle α) with respect to the direction perpendicular to the direction; It may be formed to extend (not shown). By forming the embedded surface 28, the embedded portion 24 can be formed on a flat surface, which facilitates the formation of the embedded portion and the embedding of the cutting blade in the embedded portion. Furthermore, by adopting the configuration shown in FIG. 2(c), the embedding portion 24 extending in the direction orthogonal to the embedding surface 28 is formed, and the cutting blade 10 is embedded so as to be orthogonal to the embedding surface 28. , the desired rake angle can be achieved automatically. Therefore, embedding of the cutting edge into the embedding portion becomes extremely easy, and setting of the rake angle of the cutting edge becomes extremely easy.

FIG. 2(d) is a schematic plan view seen from the axial direction for explaining the structure of an end mill according to still another embodiment of the present invention. In the end mill 104 of the illustrated example, the main body 20 has a portion 20u on the upstream side in the rotational direction R of the embedded portion 24 as seen from the direction of the rotation shaft protruding from a portion 20d on the downstream side. With such a configuration, it is possible to more effectively discharge cutting waste. The depth d1 of the embedded portion on the upstream side in the rotational direction is preferably 0.50 mm to 1.50 mm, more preferably 0.50 mm to 1.00 mm. The depth d2 of the embedded portion on the downstream side in the rotation direction is preferably 0.30 mm to 1.25 mm, more preferably 0.30 mm to 0.75 mm. If d1 and d2 are within such ranges, it is possible to secure both the bonding strength of the cutting blade to the main body and the strength of the main body itself while realizing the above-described excellent cutting waste dischargeability. The ratio d1/d2 between d1 and d2 is preferably 1.20 to 1.67, more preferably 1.33 to 1.67. If the ratio d1/d2 is within such a range, there is an advantage that the structure is more resistant to the cutting conditions for processing the stacked optical films.

The above embodiments can be appropriately combined. For example, the embodiment of FIG. 2(d) may be combined with an embodiment having a rake angle of 0° as shown in FIG. 2(e); Embodiment (c) may be combined with an embodiment having a rake angle of 0°. Further, for example, for each of the embodiments of FIGS. place or more). Needless to say, suitable combinations other than those exemplified above are also included in the present invention.

B. Manufacturing method of end mill The manufacturing method of the end mill described in A above is to embed the cutting blade 10 in the embedded portion 24 of the main body 20; securing the cutting blade 10 to the embedment 24 by brazing; A brief description will be given below.

First, the main body is produced. The body can be made, for example, by processing a sintered body obtained by a powder metallurgy method well known in the industry into a cylindrical shape by a method well known in the industry. Next, an embedded portion is formed in the main body. The implant may be formed in any suitable manner. Specific examples of the forming method include laser processing and cutting. On the one hand, a cutting edge is produced. When the cutting blade has a base made of superhard material and a sintered diamond layer provided on one side of the base, the cutting blade can be produced by the following procedure: A cutting edge forming piece having a predetermined shape is cut out from a base material having a hardened diamond layer. Cutting is performed, for example, by electric discharge machining or laser machining. Next, a cutting edge can be obtained by cutting the base portion of the obtained cutting edge forming piece to reduce the thickness to a predetermined thickness. When the cutting blade is made of sintered diamond, the cutting blade can be obtained by cutting a base material of sintered diamond.

Next, the cutting blade obtained as described above is embedded in the embedded portion formed as described above (typically, the cutting blade is inserted into the embedded portion). Finally, the cutting blade is fixed to the embedding portion while the cutting blade is embedded in the embedding portion. Specifically, the cutting blade may be attached to the implant by vacuum brazing or high frequency brazing. Vacuum brazing can adhere well to the body (embedded portion) even for cutting blades containing sintered diamond. This is because residual oxygen and moisture during brazing can be removed, and therefore the oxide film on the surface of the main body can be destroyed and regeneration of the oxide film can be prevented, so that the wettability of the surface of the main body can be increased. High-frequency brazing enables processing at low temperatures. When the cutting blade has a base and a sintered diamond layer, both the base and the sintered diamond layer are fixed to the main body (embedded portion); when the cutting blade is made of sintered diamond, A sintered diamond is fixed to the body (embedded portion).

C. Method of Using End Mills The end mills described in the above sections A and B are typically suitable for use in the method for producing an optical film. The manufacturing method preferably includes cutting the 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 treatment film, and for these purposes Appropriately laminated laminates (for example, antireflection circularly polarizing plate, polarizing plate with conductive layer for touch panel) may be mentioned. In one embodiment, the optical film includes an adhesive layer (eg, adhesive layer, adhesive layer). By using the end mill according to the embodiment of the present invention, it is possible to suppress adhesive chipping during cutting even for an optical film including an adhesive layer.

A method for producing a polarizing plate with an adhesive layer as an example of an optical film will be described below. Specifically, each step in the method for manufacturing a planar pressure-sensitive adhesive layer-attached polarizing plate as shown in FIG. 3 will be described. It is obvious to those skilled in the art that the optical film is not limited to the adhesive layer-attached polarizing plate, and that the planar shape of the adhesive layer-attached polarizing plate is not limited to the planar shape shown in FIG. That is, the end mill according to the embodiment of the present invention can be applied to any optical film manufacturing method of any shape.

C-1. Formation of Work FIG. 4 is a schematic perspective view for explaining cutting of an optical film, and a work 200 is shown in this figure. As shown in FIG. 4, a workpiece 200 is formed by stacking a plurality of optical films (polarizing plates with adhesive layers). Since the pressure-sensitive adhesive layer-attached polarizing plate can be manufactured by a method well known and commonly used in the industry, detailed description of the manufacturing method is omitted. The pressure-sensitive adhesive layer-attached polarizing plate is typically cut into any appropriate shape when forming a work. Specifically, the pressure-sensitive adhesive layer-attached polarizing plate may be cut into a rectangular shape, may be cut into a shape similar to the rectangular shape, or may be cut into an appropriate shape (for example, a circle) according to the purpose. may have been In the illustrated example, the pressure-sensitive adhesive layer-attached polarizing plate is cut into a rectangular shape, and the workpiece 200 has outer peripheral surfaces (cut surfaces) 200a and 200b facing each other and outer peripheral surfaces (cut surfaces) 200c and 200d orthogonal thereto. have. The workpiece 200 is preferably clamped from above and below by clamping means (not shown). The total thickness of the work is preferably 10 mm to 50 mm, more preferably 15 mm to 25 mm, still more preferably about 20 mm. With such a thickness, it is possible to prevent damage due to pressure from the clamping means or impact during cutting. The pressure-sensitive adhesive layer-attached polarizing plates are stacked so that the work has such a total thickness. The number of pressure-sensitive adhesive layer-attached polarizing plates constituting the work may be, for example, 20 to 100. The clamping means (e.g., jig) may be composed of a soft material or a hard material. When composed of a soft material, its hardness (JIS A) is preferably 60° to 80°. If the hardness is too high, there may be impressions left by the clamping means. If the hardness is too low, the deformation of the jig may cause misalignment, resulting in insufficient cutting accuracy.

C-2. End Mill Machining Next, a predetermined position on the outer peripheral surface of the workpiece 200 is cut by the end mill 100 . The end mill 100 is typically held by a machine tool (not shown), rotated at high speed around the rotation axis of the end mill, and sent out in a direction intersecting the rotation axis so that the cutting edge is applied to the outer peripheral surface of the workpiece 200. It is used by contacting and cutting. That is, cutting is typically performed by bringing a cutting edge of an end mill into contact with the outer peripheral surface of the workpiece 200 to cut. In the case of producing a polarizing plate with an adhesive layer having a shape in plan view as shown in FIG. A concave portion 200I is formed in the central portion of the outer peripheral surface connecting to 200H.

The cutting of the workpiece 200 will be explained in detail. First, as shown in FIG. 5(a), the portion where the chamfered portion 200E of FIG. 2 is formed is chamfered, and then, as shown in FIGS. The portions where 200G and 200H are formed are sequentially chamfered. Finally, as shown in FIG. 5(e), recesses 200I are formed by cutting. Although chamfered portions 200E, 200F, 200G and 200H and recessed portion 200I are formed in this order in the illustrated example, they may be formed in any appropriate order.

The cutting conditions can be appropriately set according to the configuration of the pressure-sensitive adhesive layer-attached polarizing plate, the desired shape, and the like. For example, the rotation speed (number of rotations) of the end mill is preferably less than 25000 rpm, more preferably 22000 rpm or less, and even more preferably 20000 rpm or less. The lower limit of the rotation speed of the end mill can be, for example, 10000 rpm. Also, for example, the feed speed of the end mill is preferably 500 mm/min to 10000 mm/min, more preferably 500 mm/min to 2500 mm/min, still more preferably 800 mm/min to 1500 mm/min. Also, for example, the depth of cut of the end mill is preferably 0.8 mm or less, more preferably 0.3 mm or less. The number of cuts in the cut location with the end mill can be one cut, two cuts, three cuts or more.

As described above, the cut polarizing plate with an adhesive layer can be obtained using the end mill according to the embodiment of the present invention. In the illustrated example, a pressure-sensitive adhesive layer-attached polarizing plate including non-linear processed portions can be obtained.

The end mill of the present invention can be suitably used for cutting optical films. The optical film cut by the end mill of the present invention can be used, for example, in irregular-shaped image display units represented by automobile instrument panels and smart watches.

10 cutting edge 10a cutting edge 10b rake face 10c relief face 11 base 12 sintered diamond layer 20 main body 22 rotating shaft 24 embedded portion 26 reference surface 28 embedded surface 30 pocket 100 end mill 101 end mill 102 end mill 103 end mill 104 end mill 105 end mill 200 workpiece

Claims (10)

a main body provided with a plurality of embedded portions and rotating around a rotation axis; and a plurality of cutting blades configured as outermost diameters embedded in and fixed to the plurality of embedded portions, respectively;
the cutting edge comprises sintered diamond;
The helix angle of the cutting edge is 0°,
has an outer diameter of less than 10 mm,
The cutting blade is embedded and fixed in the embedded portion so that an extension line of the cutting blade does not pass through the rotation axis and defines a predetermined rake angle,
The main body is formed with a reference surface extending in a direction forming the predetermined angle with respect to the extending direction of the cutting blade.
end mill. 2. The end mill according to claim 1, wherein said main body is formed with an embedded surface extending in a direction intersecting the extending direction of said reference surface. 3. The end mill according to claim 2, wherein said main body is formed with an embedded surface extending in a direction forming said predetermined angle with respect to a direction orthogonal to an extending direction of said reference surface. In the main body, a portion on the upstream side in the rotational direction of the embedded portion when viewed from the direction of the rotation axis protrudes outward from the embedding surface more than a portion on the downstream side in the rotational direction of the embedded portion. 4. The end mill according to any one of 3. 5. The end mill according to any one of claims 1 to 4, wherein said cutting edge has a base made of superhard material and a sintered diamond layer provided on one surface of said base. The end mill according to any one of claims 1 to 5, wherein the embedded portion has a depth of 0.30 mm to 1.50 mm. The end mill according to any one of claims 1 to 6, wherein the plurality of embedded portions are provided at symmetrical positions with respect to the rotation axis. A method for manufacturing an end mill according to any one of claims 1 to 7,
embedding the cutting blade in the embedded portion of the main body; and fixing the cutting blade to the embedded portion by vacuum brazing or high-frequency brazing while the cutting blade is embedded in the embedded portion;
A manufacturing method, including: The cutting blade has a base made of a superhard material and a sintered diamond layer provided on one surface of the base,
9. The manufacturing method of claim 8, wherein both the base and the sintered diamond layer are secured to the embedding portion by vacuum brazing or high frequency brazing. The cutting blade is made of sintered diamond,
9. The manufacturing method according to claim 8, wherein the sintered diamond is fixed to the embedded portion by vacuum brazing.

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