JP7345808B2 - End mill and its manufacturing method - Google Patents

Description

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

End mills are widely known as one type of cutting tool. An end mill typically has a main body that rotates around a rotation axis and a cutting blade attached to the surface of the main body.

Japanese Patent Application Publication No. 2016-182658

Although there are many blade materials for end mills, the present inventors have considered using a sintered diamond blade as a countermeasure against wear of the cutting blade. Normal end mills are made by cutting a single piece of metal to form the blade, but sintered diamond blades are difficult to carve and form into blades, so they must be attached separately to the end mill body. Depending on the application, the end mill may be required to have a small diameter (for example, an outer diameter of less than 10 mm). Such small-diameter end mills do not have a sufficient mounting surface on the main body for attaching the cutting blade, and it is often difficult to attach the cutting blade to the main body. Furthermore, when using a plurality of cutting blades, it is often more difficult to attach the cutting blades to the main body and to 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 with a small diameter but with a plurality of cutting blades well attached to the main body, and excellent strength and durability. The object of the present invention is to provide a simple manufacturing method.

The end mill of the present invention includes a main body that rotates around a rotating shaft and is provided with a plurality of embedded parts; and a plurality of cutting blades that are embedded and fixed in the plurality of embedded parts and configured as the outermost diameter. and ; The cutting blade includes sintered diamond, the cutting blade has a helix angle of 0°, and an outer diameter of less than 10 mm. The cutting blade is embedded and fixed in the embedded portion such that an extension line of the cutting blade does not pass through the rotating shaft.
In one embodiment, the cutting blade is embedded and fixed in 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 direction in which the cutting blade extends.
In one embodiment, the main body is formed with an embedded surface extending in a direction crossing the direction in which the reference surface extends.
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 direction in which the reference surface extends.
In one embodiment, the cutting blade is embedded and fixed in the embedded portion so as to be orthogonal to the embedded surface.
In one embodiment, in the main body, an upstream side in the rotational direction of the embedded portion as seen from the rotational axis direction protrudes more than a downstream side in the rotational direction of the embedded portion.
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.
In one embodiment, the depth of the embedded portion is between 0.30 mm and 1.50 mm.
In one embodiment, the plurality of embedded parts are provided at symmetrical positions with respect to the rotation axis.
According to another aspect of the present invention, a method for manufacturing the above end mill may be provided. This manufacturing method includes embedding the cutting blade in the embedded part of the main body; and, with the cutting blade embedded in the embedded part, applying vacuum brazing or high-frequency brazing to the cutting blade in the embedded part. Including fixing.
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 Both of the sintered diamond layers are secured to the embedded portion by vacuum brazing.
In another embodiment, the cutting blade is comprised of sintered diamond, and the manufacturing method includes securing 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 part in the main body and embedding and fixing the cutting blade in the embedded part, the cutting blade is well attached to the main body, and has excellent strength and durability. It is possible to realize a new end mill. Furthermore, the strength and durability can be further improved by embedding and fixing the cutting blade in the embedded part so that the extension line of the cutting blade does not pass through the rotating shaft. As a result, even when using a plurality of cutting blades, 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 plan view of the end mill of FIG. 1(a). FIG. FIGS. 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. FIG. 2 is a schematic plan view showing an example of the shape of a non-linearly processed optical film that can be obtained by a method for manufacturing an optical film using an end mill according to an embodiment of the present invention. FIG. 2 is a schematic perspective view for explaining cutting of an optical film using an end mill according to an embodiment of the present invention. 5(a) to 5(e) are schematic plan views illustrating a series of steps of non-linear cutting, which is an example of cutting of an optical film using an end mill according to an embodiment of the present invention. .

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. Note that the drawings are shown schematically for ease of viewing, and the ratios of length, width, thickness, etc., 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 a schematic plan view of the end mill of FIG. 1(a). It is a schematic perspective view. The illustrated end mill 100 includes a main body 20 that rotates around a rotation shaft 22 that extends in the vertical direction (the direction in which the workpieces are stacked; the workpiece is an object to be cut in which optical films are laminated; details will be described later); A cutting blade 10 protruding from the cutting edge and configured as the outermost diameter. 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 part 24, and the cutting blade 10 is embedded in the embedded part 24 and fixed to the main body 20. With this 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 attached to the main body in a good manner. Therefore, it is possible to actually produce a small-diameter end mill having a practically acceptable cutting ability. Furthermore, an end mill with 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 parts 24, and the cutting blades 10 are embedded and fixed in each of the plurality of embedded parts 24. In the illustrated example, two embedded portions 24, 24 are provided, but 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, compared to a configuration in which the embedded parts are formed so that the extension line of the cutting blade passes through the rotation axis, the distance between the embedded parts (substantially, the distance between the deep parts of the embedded parts) can be reduced. can be made larger. 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 using a plurality of cutting blades, an excellent end mill as described above can be realized. In this specification, the term "extended line of the cutting blade" refers to a line extending in the length direction of the cutting blade at the midpoint in the thickness direction of the cutting blade (line E in FIG. 1(a)).

As described above, a plurality of embedded parts 24 are provided, and the number of cutting blades 10 can be set corresponding to the number of embedded parts 24. The embedded portions are preferably provided at 2 to 4 locations, more preferably at 2 to 3 locations. That is, the number of cutting blades of the end mill is preferably 2 to 4, more preferably 2 to 3. With such a configuration, the spacing between the cutting blades can be appropriately ensured, so that cutting debris can be efficiently discharged. More preferably, the number of blades is two. With such a configuration, the rigidity of the cutting blade is ensured, a pocket is secured, and 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. In addition, when the end mill has two cutting blades, they are arranged approximately 180° apart in the circumferential direction of the end mill main body, for example. If the end mill has three cutting blades, they are arranged approximately every 120° in the circumferential direction of the end mill body, for example.

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, and still more preferably 0.30 mm to 0.70 mm. be. If the depth of the embedded portion is within this range, both the strength of the cutting blade to the main body and the strength of the main body itself can be ensured. If the depth of the embedded portion is less than 0.30 mm, the strength of fixing the cutting blade to the main body may be insufficient. If the depth of the embedded portion exceeds less than 1.50 mm, the strength of the main body itself may be insufficient.

In the embodiment of the invention, the helix angle of the cutting blade 10 is 0°. With such a configuration, the optical film described later can be cut well. More specifically, when cutting using a cutting blade with a helix angle (for example, irregular shape machining or non-linear machining), the cutting surface may be tapered when viewed from the lateral direction, but when the helix angle is 0°, By using a cutting blade, it is possible to prevent the cutting surface from becoming tapered. Here, irregular processing refers to, for example, processing an optical film into a shape other than a rectangle. In particular, remarkable effects can be obtained when fine non-linear processing (deformation processing) is performed on an optical film using a small-diameter end mill. In addition, 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. means. Note that "0°" means substantially 0°, and also includes cases where the angle is slightly twisted due to processing errors 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 the embodiments of the present invention, it is possible to actually produce an end mill that has such a small outer diameter and has a practically acceptable cutting ability. As a result, for example, cracks and yellow bands in optical films can be suppressed well in fine non-linear machining (deformation machining) using such small-diameter end mills, and furthermore, when the optical film has an adhesive layer, Adhesive chipping can be effectively suppressed. Note that in this specification, the "outer diameter of the end mill" refers to the distance from the rotating shaft 22 to the cutting edge 10a twice.

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 main body 20. The cutting edge 10a may be sharp as shown in the illustrated example (for example, may have an acute apex in plan view), or may be flat. The shape of the relief surface 10c in plan view may be a straight line as in the illustrated example, a bent shape (may have two relief surfaces), or a smooth curved shape. Good too. The relief surface 10c is preferably roughened. Any suitable treatment may be employed as the surface roughening treatment. A typical example is blasting. By roughening the relief surface, when cutting an optical film and the optical film includes an adhesive layer (e.g., an adhesive layer, a pressure-sensitive adhesive layer), the adhesive or Adhesion of the adhesive is suppressed, and as a result, blocking can be suppressed. In this specification, "blocking" refers to a phenomenon in which the optical films on the workpiece adhere to each other with the adhesive or adhesive on the end surfaces when the optical films include an adhesive layer, and the adhesive or adhesive attached to the end surfaces is scraped. The residue contributes to adhesion between optical films.

The cutting blade 10 may be embedded and fixed in the embedded part 24 so as to define a predetermined rake angle α as shown in the illustrated example, and the rake angle may be 0° (the direction in which the cutting blade extends and the main body It may be embedded and fixed in the embedded portion 24 so that the diameter direction thereof is parallel to the diameter direction. When the rake angle is defined 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 this 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 well. can. As a result, cracks and yellow bands in the optical film can be well suppressed when cutting the optical film, and furthermore, when the optical film has an adhesive layer, adhesive chipping can be well suppressed. Note that if the rake angle α is too large, it may become difficult to attach the cutting blade to the main body. The clearance angle β of the cutting blade 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 cutting edge angle γ from becoming excessively small. As a result, cracks and yellow bands in the optical film can be well suppressed when cutting the optical film, and furthermore, when the optical film has an adhesive layer, adhesive chipping can be well suppressed. In addition, the life of the cutting blade can be increased. The cutting edge angle γ of the cutting blade 10 is preferably 45° or more, more preferably 55° or more. If the cutting edge angle γ is within this range, the life of the cutting blade can be increased. The cutting edge angle γ is less than 85°, preferably 80° or less, and more preferably 75° or less, taking into account the rake angle α and clearance angle β. Note that in this specification, the "rake angle α" is the angle between the straight line connecting the cutting edge 10a and the rotating shaft 22 and the rake surface 10b; the "relief angle β" is the angle between the cutting surface of the workpiece 200 and the relief surface 10c. "Blade 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 invention, cutting blade 10 includes sintered diamond. With such a configuration, fine non-linear machining (deformation machining) using a small-diameter end mill as described above can be performed satisfactorily. More specifically, the cutting blade 10 may be made of sintered diamond (may be substantially made of sintered diamond), or may be made of sintered diamond as in the illustrated example. Good too. In the illustrated example, the cutting blade 10 includes a base 11 and a sintered diamond layer 12 provided on one surface of the base 11 (the downstream surface in the rotation direction R of the end mill). The surface of the sintered diamond layer 12 becomes the rake face 10b of the cutting blade. With the illustrated example configuration, processing and cutting out of the cutting blade is easy. Furthermore, in the illustrated example, the effect of providing the embedded portion is significant. Details are as follows. When a cutting blade with such a laminated structure is attached to the main body, the attachment is typically performed by brazing, but due to the laminated structure, the heat shrinkability differs between the base side and the sintered diamond layer side. As a result, the cutting blade often warps when attached 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 embedded part of the main body while being embedded, it is possible to attach the cutting blade even if the cutting blade is warped.

In the illustrated example, the thickness of the base 11 may be, for example, 0.2 mm to 2.0 mm. A typical example of the cemented carbide material constituting the base portion 11 is cemented carbide. Cemented carbide typically refers to a composite material in which carbides of metals from groups IVa, Va, and VIa of the periodic table are sintered with iron-based metals such as Fe, Co, and Ni. Specific examples of cemented carbide include WC-Co alloy, WC-TiC-Co alloy, WC-TaC-Co alloy, WC-TiC-TaC-Co alloy, WC-Ni alloy, and WC-Ni. -Cr-based alloys are mentioned. The thickness of the sintered diamond layer 12 may be, for example, 0.5 mm to 1.5 mm. The sintered diamond constituting the sintered diamond layer 12 is typically polycrystalline diamond made by sintering small diamond particles together with a binder (eg, metal powder, ceramic powder) at high temperature and high pressure. The properties of sintered diamond can be adjusted by changing the type and blending ratio of the binder.

The cutting blade 10 is preferably an integral piece with no seam along the length direction (rotation axis direction) of the main body 20. Cutting ability, strength and durability can be further improved by having the cutting blade be a seamless piece. The length of the cutting blade 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, thereby improving the efficiency of cutting.

Hereinafter, some representative examples of the modified examples of the present invention will be described.

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. In the illustrated end mill 101, a reference surface 26 is formed on the main body 20. The reference surface 20 extends in a direction forming the above-mentioned predetermined angle (the angle of the rake angle α) with respect to the direction in which the cutting blade 10 extends. 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. 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 blade can be easily set. Note that in FIG. 2A, the reference plane 26 is formed on two side surfaces of the main body 20, but the reference plane 26 may be formed only on one side surface.

FIGS. 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. The illustrated end mills 102 and 103 each further have an embedded surface 28 formed in the main body 20. The buried surface 28 is a flat surface, and the buried portion 24 is formed on the flat surface. The embedded surface 28 is typically formed in a direction intersecting the direction in which the reference surface extends. The embedded surface 28 may be formed, for example, to extend in a direction perpendicular to the direction in which the reference surface extends, as shown in FIG. 2(b); It may be formed to extend in a direction that forms the above-mentioned predetermined angle (angle of rake angle α) with respect to the direction perpendicular to the direction; in a direction that defines any appropriate angle with respect to the direction in which the reference surface extends. It may also be formed to extend (not shown). By forming the embedded surface 28, the embedded portion 24 can be formed on a flat surface, making it easier to form the embedded portion and to embed the cutting blade in the embedded portion. Furthermore, by adopting a configuration as shown in FIG. 2(c), the embedded portion 24 extending in a direction perpendicular to the embedded surface 28 is formed, and the cutting blade 10 is embedded perpendicularly to the embedded surface 28. , the desired rake angle can be automatically achieved. Therefore, it is extremely easy to embed the cutting blade in the embedded portion, and it is also extremely easy to set the rake angle of the cutting blade.

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 illustrated end mill 104, in the main body 20, a portion 20u on the upstream side in the rotation direction R of the embedded portion 24 when viewed from the rotation axis direction protrudes more than a portion 20d on the downstream side. With such a configuration, cutting debris can be discharged even better. 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 rotational 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 achieve both the adhesion strength of the cutting blade to the main body and the strength of the main body itself, while achieving the above-mentioned excellent cutting waste discharge performance. 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 in such a range, there is an advantage that the structure can withstand the cutting conditions of stacked optical film processing more easily.

The above embodiments can be combined as appropriate. For example, as shown in FIG. 2(e), the embodiment of FIG. 2(d) may be combined with an embodiment in which the rake angle is 0°; FIG. 2(a), FIG. 2(b), or FIG. The embodiment (c) may be combined with the embodiment in which the rake angle is 0°. For example, for each of the embodiments shown in FIGS. 2(a) to 2(e), the number of cutting blades may be three (three embedded parts), or four or more (four embedded parts). ) may be used. Needless to say, suitable combinations of the above embodiments other than those exemplified are also encompassed by the present invention.

B. End mill manufacturing method The end mill manufacturing method described in item A above includes embedding the cutting blade 10 in the embedded part 24 of the main body 20; and, with the cutting blade 10 embedded in the embedded part 24, vacuum brazing or high frequency This includes fixing the cutting blade 10 to the embedded portion 24 by brazing. A brief explanation will be given below.

First, the main body is manufactured. The main body can be produced, for example, by processing a sintered body obtained by a powder metallurgy method well known in the art into a cylindrical shape by a method well known in the art. 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. Meanwhile, a cutting blade is manufactured. If the cutting blade has a base made of a cemented carbide material and a sintered diamond layer provided on one side of the base, the cutting blade may be made by the following steps: first, the base and the sintered diamond layer are provided on one side of the base. A cutting blade-forming piece of a predetermined shape is cut out from a base material having a crystalline diamond layer. The cutting is performed, for example, by electric discharge machining or laser machining. Next, a cutting blade can be obtained by cutting the base of the obtained cutting blade 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 part formed as described above (typically, the cutting blade is inserted into the embedded part). Finally, with the cutting blade embedded in the embedded part, the cutting blade is fixed to the embedded part. Specifically, the cutting blade may be secured to the implant by vacuum brazing or high frequency brazing. Vacuum brazing can effectively fix even a cutting blade containing sintered diamond to the main body (embedded part). This is because residual oxygen and moisture during brazing can be removed, thereby destroying the oxide film on the surface of the main body and preventing regeneration of the oxide film, thereby increasing the wettability of the surface of the main body. High-frequency brazing allows processing at low temperatures. In addition, 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 part); when the cutting blade is composed of sintered diamond, Sintered diamond is fixed to the main body (embedded part).

C. How to Use End Mill The end mill described in Sections A and B above can typically be suitably used in a method for producing an optical film. The manufacturing method preferably includes cutting the end face of the optical film.

Specific examples of optical films include polarizers, retardation films, polarizing plates (typically laminates of polarizers and protective films), conductive films for touch panels, surface treatment films, and films for these purposes. A laminate suitably laminated according to the purpose (for example, a circularly polarizing plate for antireflection, a polarizing plate with a conductive layer for a touch panel) can be mentioned. In one embodiment, the optical film includes an adhesive layer (eg, an adhesive layer, a pressure-sensitive 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 when the optical film includes an adhesive layer.

Hereinafter, a manufacturing method when a polarizing plate with an adhesive layer is employed as an example of an optical film will be described. Specifically, each step in the method for manufacturing a planar polarizing plate with an adhesive layer 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 a polarizing plate with an adhesive layer, and that the planar shape of the polarizing plate with an adhesive layer is not limited to the planar shape of FIG. 3. That is, the end mill according to the embodiment of the present invention can be applied to a method for manufacturing any optical film having any shape.

C-1. Formation of Workpiece FIG. 4 is a schematic perspective view for explaining cutting of an optical film, and a workpiece 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 adhesive layer-attached polarizing plate can be manufactured by a method well known and commonly used in the industry, a detailed explanation of the manufacturing method will be omitted. The adhesive layer-attached polarizing plate is typically cut into any appropriate shape when forming the workpiece. Specifically, the polarizing plate with an adhesive layer may be cut into a rectangular shape, a shape similar to a rectangular shape, or an appropriate shape (for example, circular) depending on the purpose. may have been done. In the illustrated example, the polarizing plate with an adhesive layer is cut into a rectangular shape, and the workpiece 200 has outer circumferential surfaces (cut surfaces) 200a and 200b facing each other and outer circumferential surfaces (cut surfaces) 200c and 200d perpendicular thereto. have. The workpiece 200 is preferably clamped from above and below by clamping means (not shown). The total thickness of the workpiece is preferably 10 mm to 50 mm, more preferably 15 mm to 25 mm, and even more preferably about 20 mm. Such a thickness can prevent damage caused by pressure from the clamping means or impact during cutting. Polarizing plates with adhesive layers are stacked so that the workpieces have such a total thickness. The number of adhesive layer-coated polarizing plates constituting the workpiece may be, for example, 20 to 100. The clamping means (e.g. jig) may be constructed of soft or hard material. When it is made of a soft material, its hardness (JIS A) is preferably 60° to 80°. If the hardness is too high, pressure marks caused by the clamping means may remain. If the hardness is too low, positional deviation may occur due to deformation of the jig, resulting in insufficient cutting accuracy.

C-2. End Mill Processing 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 in a machine tool (not shown), rotated at high speed around the rotation axis of the end mill, and is fed out in a direction intersecting the rotation axis to apply a cutting blade to the outer peripheral surface of the workpiece 200. It is used by making abutment and cutting. That is, cutting is typically performed by bringing a cutting blade of an end mill into contact with the outer circumferential surface of the workpiece 200 to make a cut. When producing a polarizing plate with an adhesive layer having a planar view shape as shown in FIG. A concave portion 200I is formed in the center of the outer peripheral surface connecting the concave portion 200H.

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 FIG. 5(b) to FIG. The portions where 200G and 200H are formed are sequentially chamfered. Finally, as shown in FIG. 5(e), a recess 200I is formed by cutting. In the illustrated example, the chamfered portions 200E, 200F, 200G, and 200H and the recessed portion 200I are formed in this order, but they may be formed in any appropriate order.

The cutting conditions can be appropriately set depending on the configuration of the adhesive layer-attached polarizing plate, the desired shape, etc. For example, the rotation speed (rotation speed) of the end mill is preferably less than 25,000 rpm, more preferably 22,000 rpm or less, and even more preferably 20,000 rpm or less. The lower limit of the rotation speed of the end mill may be, for example, 10,000 rpm. Further, for example, the feed speed of the end mill is preferably 500 mm/min to 10,000 mm/min, more preferably 500 mm/min to 2,500 mm/min, and even more preferably 800 mm/min to 1,500 mm/min. For example, the cutting depth of the end mill is preferably 0.8 mm or less, more preferably 0.3 mm or less. The number of times the end mill cuts the cut portion may be one time, two times, three times, or more.

As described above, a 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 polarizing plate with an adhesive layer including a non-linearly processed portion 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 irregularly shaped image display parts such as automobile instrument panels and smart watches.

10 Cutting blade 10a Cutting edge 10b Rake surface 10c Relief surface 11 Base 12 Sintered diamond layer 20 Main body 22 Rotating shaft 24 Embedded part 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 Work

Claims (10)

A main body that rotates around a rotation axis and is provided with a plurality of embedded parts; and a plurality of cutting blades configured as the outermost diameter, embedded and fixed in the plurality of embedded parts, respectively;
the cutting blade includes sintered diamond;
The helix angle of the cutting blade is 0°,
The outer diameter is less than 10 mm,
The cutting blade is embedded and fixed in the embedded part in such a way that an extension line of the cutting blade does not pass through the rotation axis and defines a rake angle of a predetermined angle,
A reference surface is formed on the main body and extends in a direction forming the predetermined angle with respect to the direction in which the cutting blade extends.
end mill. The end mill according to claim 1, wherein the main body is formed with an embedded surface extending in a direction crossing the direction in which the reference surface extends. The end mill according to claim 2, wherein 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 direction in which the reference surface extends. From claim 1, wherein in the main body, a portion of the embedded portion on the upstream side in the rotational direction when viewed from the rotational axis direction protrudes more outwardly of the embedded surface than a portion on the downstream side in the rotational direction of the embedded portion. 3. The end mill according to any one of 3. The end mill according to any one of claims 1 to 4, wherein the cutting blade has a base made of a superhard material and a sintered diamond layer provided on one surface of the base. The end mill according to claim 1, 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 parts 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 part of the main body; and fixing the cutting blade in the embedded part by vacuum brazing or high frequency brazing while the cutting blade is embedded in the embedded part;
manufacturing methods, 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 according to claim 8, wherein both the base and the sintered diamond layer are fixed to the embedded part 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 part by vacuum brazing.

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