TWI875041B - End milling cutter and manufacturing method thereof - Google Patents

Abstract

Provided is an end milling cutter and a simple manufacturing method thereof: although it is a small diameter, a plurality of cutting blades can still be well mounted on a main body, and the strength and durability are excellent. The end milling cutter of the present invention comprises: a main body, provided with a plurality of embedded parts and rotating around a rotation axis; a plurality of cutting blades, which are respectively embedded in the plurality of embedded parts to be fixed and constituted as the outermost diameter. The end milling cutter is a cutting blade containing a sintered diamond, the helix angle of the cutting blade is 0°, and the outer diameter is less than 10 mm. The cutting blade is embedded in the embedded part and fixed in a manner that the extension line of the cutting blade does not pass through the rotation axis. The manufacturing method of the end milling cutter of the present invention comprises the following steps: embedding a cutting blade in an embedding portion of a main body; and fixing the cutting blade to the embedding portion by vacuum brazing or high-frequency brazing while the cutting blade is embedded in the embedding portion.

Description

End milling cutter and manufacturing method thereof

Invention Field

The present invention relates to an end milling cutter and a manufacturing method thereof.

Invention background

End milling cutters are widely known as a type of cutting tool. Typically, end milling cutters have a main body that rotates around a rotation axis and a cutting blade mounted on the surface of the main body.

Prior art literature

Patent Literature

Patent document 1: Japanese Patent Publication No. 2016-182658

Summary of invention

Although there are many materials for the blade of the end mill, the inventors of the present invention are considering using a sintered diamond blade as a countermeasure for the wear of the cutting blade. Although the conventional end mill is formed by cutting a single piece of metal, it is difficult to form a blade by cutting a sintered diamond blade, and it needs to be separately mounted on the main body of the end mill. Depending on the application, a small diameter end mill (for example, an outer diameter less than 10 mm) is sometimes required. Such a small diameter end mill often has the following situation: it is difficult to mount the cutting blade on the main body because the mounting surface for mounting the cutting blade cannot be fully ensured. Furthermore, when using multiple cutting blades, it is often more difficult to install the cutting blades on the main body and ensure their strength and durability.

This invention is constructed to solve the above-mentioned problems. Its main purpose is to provide the following end milling cutter and its simple manufacturing method: although it is a small diameter, multiple cutting blades can still be well installed on the main body, and it has good strength and durability.

The end milling cutter of the present invention has: a main body, which is provided with a plurality of embedded parts and rotates around a rotating shaft; a plurality of cutting blades, which are respectively embedded in the plurality of embedded parts to be fixed and constituted as the outermost diameter. The cutting blade includes a sintered diamond, the helix angle of the cutting blade is 0°, and the outer diameter is less than 10mm. The cutting blade is embedded in the embedded part and fixed in a manner that the extension line of the cutting blade does not pass through the rotating shaft.

In one embodiment, the cutting blade is embedded in the embedding portion and fixed in a manner that defines a predetermined angle.

In one embodiment, a reference plane is formed on the main body, and the reference plane extends in a direction forming the predetermined angle relative to the extension direction of the cutting blade.

In one embodiment, a buried surface is formed in the main body, and the buried surface extends in a direction intersecting with the extension direction of the reference surface.

In one embodiment, an embedded surface is formed in the main body, and the embedded surface extends in a direction forming the predetermined angle relative to a direction orthogonal to the extension direction of the reference surface.

In one embodiment, the cutting blade is embedded in the embedding portion and fixed in a manner perpendicular to the embedding surface.

In one embodiment, the main body is such that the upstream side of the embedded portion in the rotation direction protrudes further than the downstream side of the embedded portion in the rotation direction when viewed from the rotation axis.

In one embodiment, the cutting blade has a base made of a superhard material and a sintered diamond layer provided on one side of the base.

In one embodiment, the depth of the embedded portion is 0.30 mm to 1.50 mm.

In one embodiment, the plurality of embedded parts are arranged at positions symmetrical with respect to the rotation axis.

According to another arrangement of the present invention, a manufacturing method of the end milling cutter can be provided. The manufacturing method comprises the following steps: embedding the cutting blade in the embedding portion of the main body; and fixing the cutting blade to the embedding portion by vacuum brazing or high frequency brazing while the cutting blade is embedded in the embedding portion.

In one embodiment, the cutting blade has a base made of a superhard material and a sintered diamond layer provided on one side of the base, and the manufacturing method is to fix both the base and the sintered diamond layer to the embedded portion by vacuum brazing.

In another embodiment, the cutting blade is made of sintered diamond, and the manufacturing method is to fix the sintered diamond to the embedded portion by vacuum brazing.

According to the present invention, in a small-diameter end milling cutter, an embedded portion is provided in the main body and the cutting blade is embedded in the embedded portion for fixing, thereby realizing an end milling cutter with good strength and durability in which the cutting blade is well mounted on the main body. Furthermore, the cutting blade is embedded in the embedded portion and fixed in a manner that the extension line of the cutting blade does not pass through the rotating shaft, thereby further improving the strength and durability. As a result, even if multiple cutting blades are used, an excellent end milling cutter as described above can be realized.

10: Cutting blade

10a: Blade tip

10b: Slope

10c: Gap surface

11: Base

12: Sintered diamond layer

20: Subject

20d: Downstream part

20u: upstream part

22: Rotation axis

24: Embedded part

26: Baseline

28: Embedded surface

30: Crumb hole

100~105: End milling cutter

200: Workpiece

200a, 200b, 200c, 200d: outer surface

200E, 200F, 200G, 200H: Chamfered part

200I: Recess

d, d1, d2: depth

E: Extension line of cutting blade

R: Rotation direction

α: Bevel angle

β: Clearance angle

γ: Blade tip angle

FIG1(a) is a schematic plan view from the axial direction for illustrating the structure of an end milling cutter of one embodiment of the present invention; FIG1(b) is a schematic three-dimensional view of the end milling cutter of FIG1(a).

Figures 2(a) to 2(e) are schematic plan views from the axial direction for illustrating the structure of the end milling cutter of other embodiments of the present invention.

FIG3 is a schematic plan view showing an example of the shape of an optical film that can be obtained by using the method for manufacturing an optical film using an end milling cutter of an embodiment of the present invention through non-linear processing.

FIG4 is a schematic three-dimensional diagram for explaining the cutting process of an optical film using an end milling cutter in an embodiment of the present invention.

Figures 5(a) to 5(e) are schematic plan views illustrating an example of optical film cutting processing using an end milling cutter of an embodiment of the present invention, that is, a series of non-straight line cutting processes.

The form used to implement the invention

Although the following is a reference to the drawings to illustrate the specific implementation forms of the present invention, the present invention is not limited to such implementation forms. In addition, the drawings are schematically shown for ease of viewing, and the ratios of length, width, thickness, etc., and angles in the drawings are different from the actual ones.

A. End milling cutter

FIG. 1( a ) is a schematic plan view from the axial direction for illustrating the structure of an end milling cutter of one embodiment of the present invention; FIG. 1( b ) is a schematic three-dimensional view of the end milling cutter of FIG. 1( a ). The end milling cutter 100 shown in the figure has: a main body 20, which rotates around a rotation axis 22 extending in a vertical direction (the lamination direction of a workpiece, the workpiece is a cutting object laminated with an optical film, and the details are described later); and a cutting blade 10, which protrudes from the main body 20 and is configured as the outermost diameter. The end milling cutter is typically a straight shank end milling cutter. In the embodiment of the present invention, an embedded portion 24 is provided in the main body 20, and the cutting blade 10 is embedded in the embedded portion 24 to be fixed to the main body 20. If it is constructed in this way, even if the end milling cutter is of small diameter and it is difficult to fully ensure the mounting surface of the cutting blade on the main body surface, the cutting blade can be well mounted on the main body. Therefore, a small-diameter end milling cutter with a practically permissible cutting ability can be actually produced. Furthermore, an end milling cutter with good strength and durability can be achieved. In the embodiment of the present invention, a plurality of embedded portions 24 are provided in the main body 20, and the cutting blade 10 is respectively embedded in the plurality of embedded portions 24 to be fixed. Although two embedded portions 24, 24 are provided in the illustrated example, more than three embedded portions may be provided. That is, the number of cutting blades may be two or more than three. Furthermore, in addition to the above-mentioned structure, the embodiment of the present invention further embeds and fixes the cutting blade 10 in the embedding portion 24 in a manner that the extension line of the cutting blade 10 does not pass through the rotation axis 22. If such a structure is adopted, the mutual distance between the embedding portions (in fact, the mutual distance between the deep portions of the embedding portions) can be increased compared to a structure in which the extension line of the cutting blade passes through the rotation axis. As a result, the strength and durability of the main body 20 can be further improved, and ultimately, the strength and durability of the end milling cutter can be further improved. As a result, even if a plurality of cutting blades are used, an excellent end milling cutter as described above can be realized. In addition, in this specification, the "extension line of the cutting blade" refers to a line extending from the midpoint in the thickness direction of the cutting blade toward the length direction of the cutting blade (line E in FIG. 1(a)).

As mentioned above, there are a plurality of embedded parts 24, and the number of cutting blades 10 can be set corresponding to the number of embedded parts 24. It is preferable to set the embedded parts at 2 to 4 places, and more preferably at 2 to 3 places. That is, the number of cutting blades of the end milling cutter is preferably 2 to 4, and more preferably 2 to 3. If it is configured in this way, the cutting chips can be discharged well because the interval between the cutting blades can be properly ensured. It is better to have 2 blades. If it is configured in this way, the rigidity of the cutting blade can be ensured, and the chip pocket can be ensured to discharge the cutting chips well. The above-mentioned multiple embedded parts should be arranged at positions symmetrical with respect to the rotating shaft 22. If it is configured in this way, it is possible not only to achieve good cutting but also to further enhance the strength and durability of the end milling cutter. In addition, when the end milling cutter has two cutting blades, they are arranged about 180° apart in the circumferential direction of the end milling cutter body. When the end milling cutter has three cutting blades, they are arranged about 120° apart in the circumferential direction of the end milling cutter body.

In the example shown in the figure, the depth d of the embedded portion 24 is preferably 0.30mm~1.50mm, more preferably 0.30mm~1.00mm, and even more preferably 0.30mm~0.70mm. If the depth of the embedded portion is within such a range, both the strength of the cutting blade fixed to the main body and the strength of the main body itself can be ensured. When the depth of the embedded portion is less than 0.30mm, the strength of the cutting blade fixed to the main body may be insufficient. When the depth of the embedded portion exceeds and is less than 1.50mm, the strength of the main body itself may be insufficient.

In the embodiment of the present invention, the helix angle of the cutting blade 10 is 0°. If it is configured in this way, the optical film described later can be cut well. In more detail, when using a cutting blade with a helix angle for cutting (for example, irregular processing or non-straight processing), sometimes the cut surface becomes conical when viewed from the horizontal direction. Therefore, by using a cutting blade with a helix angle of 0°, the cut surface can be prevented from becoming conical. Here, irregular processing refers to, for example, processing the optical film into a shape other than a rectangle. In particular, a significant effect can be obtained when using a small-diameter end mill to perform fine non-straight processing (irregular processing) on the optical film. In addition, in this manual, "the helix 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 spiral relative to the rotation axis. In addition, "0°" means substantially 0°, and it also includes the case where there is a slight angle spiral due to processing errors, etc.

In the embodiment of the present invention, the outer diameter of the end mill is less than 10 mm, preferably 3 mm to 9 mm, and more preferably 4 mm to 7 mm. According to the embodiment of the present invention, an end mill with such a small outer diameter and a practically permissible cutting capacity can be actually manufactured. As a result, for example, in fine non-linear processing (special-shaped processing) using such a small-diameter end mill, the cracking and yellowing of the optical film can be well suppressed, and when the optical film has a bonding layer, the lack of glue at the end due to processing can be well suppressed. In addition, in this description, "the outer diameter of the end mill" refers to twice the distance from the rotating shaft 22 to the blade tip 10a.

The cutting blade 10 typically includes a blade tip 10a, a chamfer 10b, and a gap surface 10c. The chip pocket 30 can be defined by the chamfer 10b and the main body 20. The blade tip 10a can be sharp as shown in the example in the figure (for example, it can also be a vertex with a sharp angle when viewed from above), or it can be flat. The top view shape of the gap surface 10c can be a straight line as shown in the example in the figure, or it can be a curved shape (it can also have two gap surfaces), or it can be a smooth curve. The gap surface 10c is preferably roughened. The roughening treatment can be any appropriate treatment. Sandblasting can be cited as a representative example. By roughening the gap surface, even if the optical film contains a bonding layer (e.g., a bonding agent layer, an adhesive layer) during cutting, the bonding agent or adhesive can be prevented from adhering to the cutting blade, thereby preventing blocking. In this specification, "blocking" refers to the phenomenon that when the optical film contains a bonding layer, the optical films of the workpiece are bonded to each other by the bonding agent or adhesive on the end surface, and the shavings of the bonding agent or adhesive attached to the end surface promote the bonding of the optical films.

The cutting blade 10 may be embedded in the embedding portion 24 and fixed in a manner of defining a predetermined bevel angle α as shown in the example, or may be embedded in the embedding portion 24 and fixed in a manner of making the bevel angle 0° (the direction in which the cutting blade extends is parallel to the diameter direction of the main body). When the bevel angle is defined as shown in the example, the bevel angle α is preferably 5° to 45°, and more preferably 5° to 30°. If the bevel angle α is within such a range, the sharpness of the blade can be ensured, the resistance during the cutting process can be appropriately suppressed, and the chip pocket 30 can be made of an appropriate size to discharge the cutting chips well. As a result, when the optical film is cut, the cracking and yellowing of the optical film can be well suppressed, and when the optical film has a bonding layer, the lack of glue at the end due to processing can be well suppressed. In addition, if the bevel angle α is too large, the cutting blade may be difficult to install on the main body. The gap angle β of the cutting blade 10 is preferably 5°~30°, and more preferably 5°~25°. If the gap angle β is within such a range, the gap surface 10c can be prevented from contacting the workpiece 200, and the resistance during the cutting process can be appropriately suppressed. Furthermore, the tip angle γ can be prevented from becoming too small. As a result, when the optical film is cut, the cracking and yellowing of the optical film can be well suppressed, and when the optical film has a bonding layer, the lack of glue at the end due to processing can be well suppressed. In addition, the life of the cutting blade can be increased. The tip angle γ of the cutting blade 10 is preferably greater than 45°, and more preferably greater than 55°. If the blade tip angle γ is within such a range, the life of the cutting blade can be increased. Considering the bevel angle α and the clearance angle β, the blade tip angle γ is preferably less than 85°, more preferably less than 80°, and more preferably less than 75°. In addition, in this specification, "bevel angle α" is the angle formed by the straight line connecting the blade tip 10a and the rotation axis 22, and the bevel surface 10b; "clearance angle β" is the angle formed by the cutting surface of the workpiece 200 and the clearance surface 10c; "blade tip angle γ" is the angle defined with the blade tip 10a as the vertex, and is calculated from the formula: 90°-bevel angle α-clearance angle β.

In the embodiment of the present invention, the cutting blade 10 includes sintered diamond. If it is so constituted, fine non-linear processing (special-shaped processing) performed using a small-diameter end mill as described above can be well performed. In more detail, the cutting blade 10 can be composed of sintered diamond (can be substantially made of sintered diamond), or can be composed of sintered diamond as shown in the example. In the example, the cutting blade 10 has a base 11 composed of a superhard material, and a sintered diamond layer 12 provided on one side of the base 11 (the side on the downstream side in the rotation direction R of the end mill). The surface of the sintered diamond layer 12 becomes the inclined surface 10b of the cutting blade. If the structure is as shown in the example in the figure, the processing and cutting of the cutting blade will be easy. Furthermore, in the example in the figure, the effect of setting the embedded part will become significant. The details are as follows. In the case of mounting such a cutting blade with a multilayer structure on the main body, it is typically mounted by brazing. Therefore, due to the multilayer structure, the thermal shrinkage of the base side and the sintered diamond layer side is different. As a result, when mounting by brazing, the cutting blade often warps, making it difficult to mount the cutting blade to the main body. According to the embodiment of the present invention, since the cutting blade is fixed in the state of being embedded in the embedded part of the main body, it is possible to mount it even if 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. The superhard material constituting the base 11 can be, representatively, a superhard alloy. Superhard alloys, representatively, refer to composite materials formed by sintering carbides of metals of Groups IVa, Va, and VIa of the Periodic Table of Elements with iron-based metals such as Fe, Co, and Ni. Specific examples of superhard alloys include WC-Co alloys, WC-TiC-Co alloys, WC-TaC-Co alloys, WC-TiC-TaC-Co alloys, WC-Ni alloys, and WC-Ni-Cr alloys. The thickness of the sintered diamond layer 12 can be, for example, 0.5 mm to 1.5 mm. The sintered diamond constituting the sintered diamond layer 12 is typically a multi-crystalline diamond formed by sintering small diamond particles together with a binder (e.g., metal powder, ceramic powder) at high temperature and high pressure. The properties of the sintered diamond can be adjusted by changing the type and mixing ratio of the binder.

The cutting blade 10 is preferably a one-piece object without joints along the length direction (rotation axis direction) of the main body 20. By making the cutting blade a one-piece object without joints, the cutting ability, strength and durability can be further improved. The length of the cutting blade in the rotation axis direction is preferably 15 mm or more, and more preferably 20 mm to 50 mm. Since such a length can be used to cut optical films, workpieces with a desired number of optical films can be cut, thereby improving the efficiency of cutting.

The following describes several representative examples of the variations of the present invention.

FIG. 2(a) is a schematic plan view from the axial direction for illustrating the structure of the end milling cutter of other embodiments of the present invention. The end milling cutter 101 shown in the figure has a reference surface 26 formed on the main body 20. The reference surface 26 extends in a direction that forms the above-mentioned predetermined angle (angle of the bevel angle α) relative to the extension direction of the cutting blade 10. In other words, the reference surface 26 extends in a direction substantially parallel to the straight line connecting the blade tip 10a and the rotation axis 22. By forming the reference surface 26, the direction of the embedded portion 24 can be easily set with the reference surface 26 as a reference, so that the bevel angle of the cutting blade is easily set. In addition, although the reference surface 26 is formed on two side surfaces of the main body 20 in FIG. 2(a), the reference surface 26 can also be formed on only one side surface.

FIG. 2(b) and FIG. 2(c) are schematic plan views from the axial direction for illustrating the structure of the end milling cutter of another embodiment of the present invention. The end milling cutters 102 and 103 shown in the figure are respectively formed with an embedded surface 28 on the main body 20. The embedded surface 28 is a flat surface, and the embedded portion 24 is formed on the flat surface. The embedded surface 28 is typically formed in a direction intersecting the extension direction of the reference surface. The embedded surface 28 can be formed by extending in a direction orthogonal to the extension direction of the reference surface as shown in FIG. 2(b); or can be formed by extending in a direction forming the above-mentioned predetermined angle (angle of the oblique angle α) relative to the direction orthogonal to the extension direction of the reference surface as shown in FIG. 2(c); or can be formed by extending in a direction defining an arbitrary appropriate angle relative to the extension direction of the reference surface (not shown). By forming the embedding surface 28, the embedding portion 24 can be formed on the flat surface, so the formation of the embedding portion and the embedding of the cutting blade into the embedding portion become easy. Furthermore, by adopting the structure shown in Figure 2 (c), as long as the embedding portion 24 extending in a direction perpendicular to the embedding surface 28 is formed, the cutting blade 10 is embedded in a manner perpendicular to the embedding surface 28, and the desired bevel angle can be automatically achieved. Therefore, it becomes very easy to embed the cutting blade into the embedding portion, and it becomes very easy to set the bevel angle of the cutting blade.

Fig. 2(d) is a schematic plan view viewed from the axial direction for illustrating the structure of the end milling cutter of other embodiments of the present invention. In the end milling cutter 104 shown in the figure, the portion 20u on the upstream side of the embedded portion 24 in the rotation direction R of the main body 20 as viewed from the rotation axis direction protrudes further than the portion 20d on the downstream side. If it is constructed in this way, the cutting chips can be discharged more effectively. The depth d1 of the upstream side in the rotation direction of the embedded portion is preferably 0.50mm~1.50mm, more preferably 0.50mm~1.00mm. The depth d2 of the downstream side in the rotation direction of the embedded portion is preferably 0.30mm~1.25mm, more preferably 0.30mm~0.75mm. If d1 and d2 are within such a range, the above-mentioned excellent chip discharge can be achieved while ensuring both the fixing strength of the cutting blade to the main body and the strength of the main body itself. The ratio of d1 to d2, d1/d2, is preferably 1.20~1.67, and more preferably 1.33~1.67. If the ratio d1/d2 is within such a range, it has the following advantages: it becomes a structure that is more easily able to withstand the cutting conditions of optical film processing under load.

The above-mentioned embodiments can be appropriately combined. For example, the embodiment of FIG. 2(d) can be combined with an embodiment with an angle of 0° as shown in FIG. 2(e); the embodiment of FIG. 2(a), FIG. 2(b) or FIG. 2(c) can be combined with an embodiment with an angle of 0°. For another example, the embodiments of FIG. 2(a) to FIG. 2(e) can be respectively changed to have 3 cutting blades (3 embedded parts), or to have 4 or more cutting blades (4 or more embedded parts). It goes without saying that the present invention also includes appropriate combinations other than the above-mentioned embodiments.

B. Manufacturing method of end milling cutter

The manufacturing method of the end milling cutter described in the above item A includes the following steps: embedding the cutting blade 10 in the embedding portion 24 of the main body 20; and fixing the cutting blade 10 to the embedding portion 24 by vacuum brazing or high-frequency brazing while the cutting blade 10 is embedded in the embedding portion 24. The following is a brief description.

First, a main body is made. The main body can be made by, for example, processing a sintered body obtained by a powder metallurgy method known in the industry into a cylindrical shape by a method known in the industry. Then, an embedded portion is formed in the main body. The embedded portion can be formed by any appropriate method. Specific examples of the forming method include laser processing and cutting processing. On the other hand, a cutting blade is made. When a cutting blade having a base made of a superhard material and a sintered diamond layer provided on one side of the base is to be made, the cutting blade can be made by the following process: First, a cutting blade forming sheet of a predetermined shape is cut out from a base material having a base and a sintered diamond layer. Cutting is performed, for example, by discharge processing or laser processing. Next, the base of the obtained cutting blade forming sheet is cut to reduce the thickness to a predetermined thickness, thereby obtaining a cutting blade. When the cutting blade is composed of sintered diamond, the cutting blade can be obtained by cutting the base material of the sintered diamond.

Next, the cutting blade obtained as described above is embedded (representatively, the cutting blade is inserted into the embedded portion) in the embedded portion formed as described above. Finally, the cutting blade is fixed to the embedded portion while being embedded in the embedded portion. Specifically, the cutting blade can be fixed to the embedded portion by vacuum brazing or high-frequency brazing. Even a cutting blade containing sintered diamonds can be well fixed to the main body (embedded portion) by vacuum brazing. This is because, since residual oxygen and moisture during brazing can be removed, the oxide film on the surface of the main body can be destroyed and the regeneration of the oxide film can be prevented, thereby increasing the wettability of the main body surface. High-frequency brazing can be processed 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 portion); when the cutting blade is composed of sintered diamond, the sintered diamond is fixed to the main body (embedded portion).

C. How to use the end milling cutter

The end mills described in Items A and B above are typically suitable for use in a manufacturing method for optical films. The manufacturing method preferably includes cutting the end face of the optical film.

Specific examples of optical films include polarizers, phase difference films, polarizing plates (typically, a laminate of a polarizer and a protective film), conductive films for touch panels, surface treatment films, and laminates of these films appropriately laminated according to the purpose (e.g., circular polarizing plates for anti-reflection, polarizing plates with conductive layers for touch panels). In one embodiment, the optical film contains a bonding layer (e.g., a bonding agent layer, an adhesive layer). By using the end milling cutter of the embodiment of the present invention, even for an optical film containing a bonding layer, the lack of glue caused by the cutting process can be suppressed.

The following describes the manufacturing method using a polarizing plate with an adhesive layer as an example of an optical film. Specifically, the steps of the manufacturing method of a polarizing plate with an adhesive layer in a planar shape as shown in FIG. 3 are described. In addition, it is obvious to the industry that optical films are not limited to polarizing plates with an adhesive layer, and the planar shape of polarizing plates with an adhesive layer is not limited to the planar shape of FIG. 3. That is, the end milling cutter of the embodiment of the present invention can be applied to the manufacturing method of any optical film of any shape.

C-1. Formation of workpiece

FIG4 is a schematic three-dimensional diagram for explaining the cutting process of an optical film, and in this figure, a workpiece 200 is shown. As shown in FIG4, a workpiece 200 having a plurality of optical films (polarizing plates with adhesive layers) stacked on top of each other is formed. Since the polarizing plates with adhesive layers can be manufactured by a method commonly known in the industry, a detailed description of the manufacturing method is omitted. When the workpiece is formed, the polarizing plates with adhesive layers are typically cut into any appropriate shape. Specifically, the polarizing plates with adhesive layers can be cut into a rectangular shape, a shape similar to a rectangular shape, or a shape appropriate for the purpose (e.g., a circular shape). In the illustrated example, the polarizing plate with an adhesive layer has been cut into a rectangular shape, and the workpiece 200 has outer peripheral surfaces (cut surfaces) 200a, 200b facing each other, and outer peripheral surfaces (cut surfaces) 200c, 200d that are orthogonal to these. The workpiece 200 is preferably clamped from the top and bottom by a clamping means (not shown). The total thickness of the workpiece is preferably 10mm~50mm, more preferably 15mm~25mm, and more preferably about 20mm. If it is such a thickness, damage caused by the pressure of the clamping means or the impact during the cutting process can be prevented. The polarizing plates with an adhesive layer are overlapped in a manner that the workpiece has such a total thickness. The number of polarizing plates constituting the adhesive layer of the workpiece can be, for example, 20 to 100. The clamping means (such as a jig) can be made of soft material or hard material. When made of soft material, its hardness (JIS A) should be 60°~80°. If the hardness is too high, there may be residual pressure marks caused by the clamping means. If the hardness is too low, the position may be offset due to the deformation of the jig, and the cutting accuracy may become insufficient.

C-2. End milling process

Next, the predetermined position of the outer circumference of the workpiece 200 is cut by the end milling cutter 100. The end milling cutter 100 is typically used as follows: it is held by a working machine (not shown), rotated at high speed around the rotating shaft of the end milling cutter, and is fed in a direction intersecting the rotating shaft while the cutting blade is brought into contact with the outer circumference of the workpiece 200 to cut. That is, cutting is typically performed as follows: the cutting blade of the end milling cutter is brought into contact with the outer circumference of the workpiece 200 to cut. When a polarizing plate with an adhesive layer having a top view shape as shown in FIG. 3 is manufactured, chamfered portions 200E, 200F, 200G, and 200H are formed at the four corners of the outer circumference of the workpiece 200, and a recessed portion 200I is formed in the central portion of the outer circumference connecting the chamfered portions 200E and 200H.

The cutting process of the workpiece 200 is described in detail. First, as shown in FIG5(a), the chamfering process is performed on the portion where the chamfered portion 200E of FIG2 is to be formed. Then, as shown in FIG5(b) to FIG5(d), the chamfering process is performed in sequence on the portions where the chamfered portions 200F, 200G, and 200H are to be formed. Finally, as shown in FIG5(e), the concave portion 200I is formed by cutting. In addition, although the example in the figure shows that the chamfered portions 200E, 200F, 200G, 200H, and the concave portion 200I are formed in this order, these can be formed in any appropriate order.

The conditions for the cutting process can be appropriately set according to the structure of the polarizing plate with the adhesive layer, the desired shape, etc. For example, the rotation speed (number of revolutions) of the end milling cutter should be less than 25000rpm, more preferably less than 22000rpm, and more preferably less than 20000rpm. The lower limit of the rotation speed of the end milling cutter can be, for example, 10000rpm. Also, for example, the feed speed of the end milling cutter should be 500mm/min~10000mm/min, more preferably 500mm/min~2500mm/min, and more preferably 800mm/min~1500mm/min. Also, for example, the cutting amount of the end milling cutter should be less than 0.8mm, and more preferably less than 0.3mm. The number of times the end milling cutter cuts the cutting part can be 1 time, 2 times, 3 times or more.

As described above, a polarizing plate with an adhesive layer that has been cut is obtained by using the end milling cutter of the embodiment of the present invention. In the example shown in the figure, a polarizing plate with an adhesive layer that has been processed in a non-linear manner is obtained.

Industrial availability

The end milling cutter of the present invention is suitable for cutting optical films. The optical films cut by the end milling cutter of the present invention can be used in irregular image display parts such as automobile instrument screens and smart watches.

10: Cutting blade

10a: Blade tip

10b: Slope

10c: Gap surface

11: Base

12: Sintered diamond layer

20: Subject

22: Rotation axis

24: Embedded part

30: Crumb hole

100: End milling cutter

200: Workpiece

d: depth

E: Extension line of cutting blade

R: Rotation direction

α: Bevel angle

β: Clearance angle

γ: Blade tip angle

Claims (10)

An end milling cutter comprises: a main body, provided with a plurality of embedded parts and rotating around a rotation axis; and a plurality of cutting blades, respectively embedded in the plurality of embedded parts to be fixed and configured as the outermost diameter, the cutting blades contain sintered diamonds, the helix angle of the cutting blades is 0°, the outer diameter is less than 10 mm, the cutting blades are embedded in the embedded parts and fixed in a manner that the extension line of the cutting blades does not pass through the rotation axis and in a manner that a predetermined angle is defined, and a reference surface is formed on the main body, and the aforementioned reference surface extends in a direction that forms the predetermined angle relative to the extension direction of the cutting blades. As in claim 1, the end milling cutter has an embedded surface formed in the main body, and the embedded surface extends in a direction intersecting with the extension direction of the reference surface. As in claim 2, the end milling cutter has an embedded surface formed in the main body, and the embedded surface extends in a direction that forms the predetermined angle relative to the direction orthogonal to the extension direction of the reference surface. As in claim 2 or 3, the end milling cutter, wherein the main body is such that when viewed from the direction of the rotation axis, the portion on the upstream side of the aforementioned embedded portion in the rotation direction protrudes further toward the outer side of the aforementioned embedded surface than the portion on the downstream side of the aforementioned embedded portion in the rotation direction. An end milling cutter as claimed in any one of claims 1 to 3, wherein the cutting blade has a base made of a superhard material and a sintered diamond layer provided on one side of the base. For an end milling cutter as claimed in any one of items 1 to 3, the depth of the embedded portion is 0.30mm~1.50mm. An end milling cutter as claimed in any one of claims 1 to 3, wherein the plurality of embedded portions are arranged at positions symmetrical with respect to the rotation axis. A manufacturing method is a manufacturing method of an end milling cutter as in any one of claims 1 to 7, comprising the following steps: embedding the aforementioned cutting blade in the aforementioned embedding portion of the aforementioned main body; and fixing the cutting blade to the embedding portion by vacuum brazing or high-frequency brazing while the cutting blade is embedded in the embedding portion. As in the manufacturing method of claim 8, the cutting blade has a base made of a superhard material and a sintered diamond layer provided on one side of the base, and the manufacturing method fixes both the base and the sintered diamond layer to the embedded portion by vacuum brazing or high frequency brazing. As in the manufacturing method of claim 8, the cutting blade is made of sintered diamond, and the manufacturing method fixes the sintered diamond to the embedded portion by vacuum brazing.