TWI808260B - End mill and manufacturing method thereof - Google Patents

Abstract

To provide an end mill and a simple manufacturing method thereof in which a plurality of cutting blades can be well attached to the main body despite having a small diameter, and has high strength and durability. The end mill of the present invention has: a main body provided with a plurality of embedded parts and rotating around a rotating shaft; and a plurality of cutting blades respectively embedded in the plurality of embedded parts to be fixed and constituted as the outermost diameter. This end mill is a cutting blade containing 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 embedding part and fixed so that the extension line of the cutting blade does not pass through the rotating shaft. The manufacturing method of the end mill of the present invention includes the following steps: embedding the cutting blade in the embedding part of the main body; and fixing the cutting blade to the embedding part by vacuum brazing or high frequency brazing in the state of embedding the cutting blade in the embedding part.

Description

End mill and manufacturing method thereof

field of invention

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

Background of the invention

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

Prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2016-182658

Summary of the invention

Although there are many materials for the blade of an end mill, the inventors of the present invention have examined the use of a sintered diamond blade as a countermeasure against wear of the cutting blade. Although the usual end mill cuts an integral metal to shape the blade, it is difficult to form the edge by cutting the sintered diamond blade, and it needs to be additionally installed on the main body of the end mill. Depending on the application, an end mill with a small diameter (such as an outer diameter below 10mm) is sometimes required. Such a small-diameter end mill often has the following situation: It is not possible to ensure sufficient mounting for the cutting edge on the main body. surface, and it is difficult to install the cutting blade on the main body. Furthermore, when a plurality of cutting blades are used, it is often more difficult to install the cutting blades to the main body, and to ensure strength and durability.

The present invention is an invention constructed to solve the above-mentioned conventional problems, and its main purpose is to provide an end mill and a simple manufacturing method thereof in which a plurality of cutting blades can be well attached to the main body despite having a small diameter, and has high strength and durability.

The end mill of the present invention has: a main body provided with a plurality of embedded parts and rotating around a rotating shaft; and a plurality of cutting blades respectively embedded in the plurality of embedded parts to be fixed and constituted as the outermost diameter. The cutting blade includes 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 embedding portion and fixed so 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 embedded portion so as to define a bevel at a predetermined angle, and fixed.

In one embodiment, a reference surface is formed on the body, and the reference surface extends in a direction forming the predetermined angle with respect to an extending direction of the cutting blade.

In one embodiment, an embedding surface is formed on the main body, and the embedding surface extends in a direction intersecting with an extending direction of the reference plane.

In one embodiment, an embedding surface is formed on the main body, and the embedding surface extends in a direction forming the predetermined angle with respect to a direction perpendicular to an extending direction of the reference plane.

In one embodiment, the cutting blade is embedded in the embedded portion and fixed so as to be perpendicular to the embedded surface.

In one embodiment, the main body protrudes more upstream in the rotational direction of the embedded portion than downstream in the rotational direction of the embedded portion when viewed in the direction of the rotational 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 portions are provided at symmetrical positions with respect to the rotational axis.

According to another configuration of the present invention, a method of manufacturing the above-mentioned end mill can be provided. The manufacturing method includes the steps of: 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 part 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 part by vacuum brazing.

According to the present invention, a small-diameter end mill is provided with an embedding portion in the main body, and the cutting blade is embedded in the embedding portion to fix the cutting blade. By this, the cutting blade is well attached to the main body, and an end mill having excellent strength and durability can be realized. Furthermore, the cutting blade is buried and fixed in the embedding portion so 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 a plurality of cutting blades are used, an excellent end mill as described above can be realized.

10: Cutting blade

10a: blade tip

10b: Bevel

10c: Clearance surface

11: base

12: Sintered diamond layer

20: subject

20d: part on the downstream side

20u: part on the upstream side

22: Rotation axis

24: Embedded part

26: Reference plane

28:Buried surface

30: chip hole

100~105: end mill

200: workpiece

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

200E, 200F, 200G, 200H: chamfering

200I: concave part

d, d1, d2: Depth

E: Extension line of cutting blade

R: direction of rotation

α: Bevel

β: clearance angle

γ: blade tip angle

Fig. 1(a) is a schematic plan view viewed from the axial direction for explaining the structure of an end mill according to an embodiment of the present invention; Fig. 1(b) is a schematic perspective view of the end mill in Fig. 1(a).

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, respectively.

3 is a schematic plan view showing an example of the shape of a non-linearly processed optical film obtained by the method of manufacturing an optical film using an end mill according to an embodiment of the present invention.

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.

5(a) to 5(e) are schematic plan views illustrating an example of dicing of an optical film using an end mill according to an embodiment of the present invention, that is, a series of processes of non-linear dicing.

form for carrying out the invention

Although the specific implementation form of the present invention is described below with reference to the drawings, state, but the present invention is not limited to these embodiments. In addition, the drawings are schematically shown for easy viewing, and ratios of length, width, thickness, etc., angles, etc. in the drawings are different from actual ones.

A. End mill

Fig. 1(a) is a schematic plan view viewed from the axial direction for explaining the structure of an end mill according to an embodiment of the present invention; Fig. 1(b) is a schematic perspective view of the end mill in Fig. 1(a). The end mill 100 illustrated in the illustration has a main body 20 that rotates around a rotating shaft 22 extending in the vertical direction (the lamination direction of the workpiece, the workpiece is an object to be cut on which an optical film is laminated, which will be described in detail later), and a cutting edge 10 that protrudes from the main body 20 and is formed as the outermost diameter. As for the end mill, it is typically a straight shank end mill. In an embodiment of the present invention, the main body 20 is provided with an embedding portion 24 , and the cutting blade 10 is embedded in the embedding portion 24 to be 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 attached to the main body. Therefore, a small-diameter end mill having a practically acceptable cutting ability can be actually manufactured. 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 blade 10 is respectively embedded in the plurality of embedded parts 24 to be fixed. In the illustrated example, two embedding portions 24, 24 are provided, but three or more embedding portions may be provided. That is, the number of cutting blades may be two, or three or more. Furthermore, in an embodiment of the present invention, in addition to the above configuration, the cutting blade 10 is buried and fixed in the embedding portion 24 so that the extension line of the cutting blade 10 does not pass through the rotating shaft 22 . If so constituted, the extension line with the cutting blade will pass through the axis of rotation Compared with the configuration in which the embedded portions are formed in a similar manner, the mutual distance between the embedded portions (essentially, the mutual distance between the deep portions of the embedded portions) 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 if a plurality of cutting blades are used, an excellent end mill as described above can be realized. In addition, in this specification, "the extension line of a cutting blade" means the line (line E of FIG.

As mentioned above, the embedding portion 24 is provided in plural, and the number of cutting blades 10 can be set corresponding to the number of embedding portions 24 . The embedded part should be set at 2~4 places, more preferably 2~3 places. That is, the number of cutting blades of the end mill should be 2 to 4, more preferably 2 to 3. According to such a structure, since the space|interval between cutting blades can be ensured suitably, cutting chips can be discharged|emitted favorably. Preferably, the number of blades is two. With such a configuration, the rigidity of the cutting blade can be ensured, and the cutting chips can be discharged well while ensuring the chip pocket. The above-mentioned plurality of embedded parts are preferably provided at symmetrical positions with respect to the rotation axis 22 . With such a configuration, it is possible not only to achieve good cutting but also to improve the strength and durability of the end mill. In addition, when there are two cutting blades of the end mill, they are arranged at a distance of about 180° in the circumferential direction of the main body of the end mill, for example. When there are three cutting blades of the end mill, they are arranged at intervals of about 120° in the circumferential direction of the main body of the end mill, for example.

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 part is within such a range, the fixing strength of the cutting blade to the main body and the strength of the main body can be ensured. degree both sides. When the depth of the embedded portion is less than 0.30mm, the strength of fixing the cutting blade to the main body may not be sufficient. When the depth of the embedded part is less than or equal to 1.50 mm, the strength of the main body itself may not be sufficient.

In the embodiment of the present invention, the helix angle of the cutting edge 10 is 0°. According to such a structure, the dicing of the optical film mentioned later can be performed favorably. More specifically, when cutting with a cutting blade with a helix angle (for example, irregular processing or non-linear processing), the cutting surface may become tapered when viewed from the horizontal direction. Therefore, by using a cutting blade with a helix angle of 0°, it is possible to suppress the cutting surface from becoming tapered. Here, "deformation processing" means, for example, processing an optical film into a shape other than a rectangle. In particular, a remarkable effect can be obtained when using a small-diameter end mill to perform fine non-linear processing (deformation processing) on an optical film. In addition, in this specification, "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 does not spiral with respect to the rotation axis. In addition, "0°" means substantially 0°, and the case where there is a slight angle twist due to processing errors and the like is also included.

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, more preferably 4 mm to 7 mm. According to the embodiment of the present invention, it is possible to actually manufacture an end mill having such a small outer diameter and having a practically acceptable cutting capability. As a result, for example, in the fine non-linear processing (special-shaped processing) performed by 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 an adhesive layer, the glue at the end can be well suppressed. And the absence of the situation. In addition, in this description, "end mill outer diameter" means twice the distance from the rotating shaft 22 to the cutting edge 10a.

The cutting edge 10 typically includes a cutting edge 10a, a slope 10b, and a clearance surface 10c. The chip cavity 30 can be defined by the inclined surface 10 b and the main body 20 . The cutting edge 10a may be sharp as shown in the figure (for example, it may be an apex having an acute angle in plan view), or may be flat. The top view shape of the gap surface 10c may be a straight line as shown in the figure, or a bent shape (also may have two gap surfaces), or a smooth curved shape. The gap surface 10c should be roughened. Any appropriate treatment may be used for the roughening treatment. Sandblasting can be given as a representative example. By applying roughening treatment to the gap surface, even if the optical film contains an adhesive layer (such as an adhesive layer, an adhesive layer) when the optical film is diced, it is possible to suppress the adhesion of the adhesive or the adhesive to the cutting blade, and as a result, it is possible to suppress blocking. In this specification, "adhesion" refers to the phenomenon that when the optical film contains an adhesive layer, the optical film of the workpiece is bonded to each other by the adhesive or adhesive on the end surface.

The cutting blade 10 may be embedded and fixed in the embedding portion 24 so as to define a predetermined bevel angle α as shown in the figure, or may be embedded in the embedding portion 24 and fixed so that the bevel angle becomes 0° (the direction in which the cutting blade extends is parallel to the diameter direction of the main body). When the bevel angle is specified as shown in the figure, the bevel angle α is preferably 5°~45°, more preferably 5°~30°. If the bevel 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 chip pocket 30 can be used as a suitable tool. Cut to size and discharge cutting chips well. As a result, when the optical film is cut and processed, cracking and yellowing of the optical film can be well suppressed, and when the optical film has an adhesive 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, it may be difficult to install the cutting blade to the main body. The clearance angle β of the cutting blade 10 is preferably 5°-30°, more preferably 5°-25°. If the clearance angle β is within such a range, the contact between the clearance surface 10c and the workpiece 200 can be prevented, and resistance during cutting can be suitably suppressed. Furthermore, it is possible to prevent the edge angle γ from becoming too small. As a result, when the optical film is cut and processed, cracking and yellowing of the optical film can be well suppressed, and when the optical film has an adhesive 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 edge angle γ of the cutting blade 10 is preferably not less than 45°, more preferably not less than 55°. If the edge angle γ is within such a range, the life of the cutting blade can be increased. In consideration of the bevel angle α and the clearance angle β, the edge angle γ is preferably less than 85°, more preferably 80° or less, and still more preferably 75° or less. In addition, in this specification, the "bevel angle α" is an angle formed by the straight line connecting the blade edge 10a and the rotating shaft 22, and the slope 10b; the "clearance angle β" is the angle formed by the cutting surface of the workpiece 200 and the clearance surface 10c;

In an embodiment of the present invention, the cutting edge 10 includes sintered diamond. With such a configuration, fine non-linear processing (deformation processing) as described above using a small-diameter end mill can be performed favorably. In more detail, the cutting edge 10 can be made of sintered diamond (can Therefore, it is actually made of sintered diamonds), or it may be composed of sintered diamonds as shown in the figure. In the illustrated example, the cutting blade 10 has a base 11 made of a superhard material, and a sintered diamond layer 12 provided on one surface of the base 11 (the surface on the downstream side in the rotation direction R of the end mill). The surface of the sintered diamond layer 12 is a slope 10b which becomes a cutting edge. According to the configuration shown in the illustration, it is easy to process and cut out the cutting blade. Furthermore, in the example shown in the figure, the effect of providing the embedded part becomes remarkable. The details are as follows. When attaching the cutting blade of such a laminated structure to the main body, it is typically mounted by brazing. Therefore, due to the laminated structure, the thermal shrinkage of the base side is different from that of the sintered diamond layer side. As a result, when mounting by brazing, the cutting blade tends to be warped, 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 a state where the cutting blade is embedded in the embedding portion of the main body, even if the cutting blade is warped, it can be attached.

In the illustrated example, the thickness of the base portion 11 may be, for example, 0.2mm˜2.0mm. The superhard material constituting the base 11 may be representatively a superhard alloy. Cemented carbide typically refers to a composite material obtained by sintering carbides of group IVa, Va, and VIa metals of the periodic table with iron-based metals such as Fe, Co, and Ni. Specific examples of superhard alloys include WC-Co-based alloys, WC-TiC-Co-based alloys, WC-TaC-Co-based alloys, WC-TiC-TaC-Co-based alloys, WC-Ni-based alloys, and WC-Ni-Cr-based alloys. The thickness of the sintered diamond layer 12 may be, for example, 0.5mm˜1.5mm. Regarding the sintered diamonds constituting the sintered diamond layer 12, typically, small diamonds and a binder (such as metal powder, Ceramic powder) together with high temperature / high pressure and sintered into blocks of multi-crystalline diamonds. The characteristics of sintered diamonds can be adjusted by changing the type and mixing ratio of the binder.

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

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. The end mill 101 of the illustrated example has a reference surface 26 formed on the main body 20 . The reference plane 20 extends in a direction forming the above-mentioned predetermined angle (the angle of the oblique angle α) with respect to the extending direction of the cutting blade 10 . In other words, the reference plane 20 extends in a direction substantially parallel to the straight line connecting the cutting edge 10 a and the rotation shaft 22 . By forming the reference plane 26, the direction of the embedding portion 24 can be easily set using the reference plane 26 as a reference. As a result, setting of the bevel angle of the cutting blade becomes easy. In addition, although the reference plane 26 is formed on two side surfaces of the main body 20 in FIG. 2( a ), the reference plane 26 may also be formed on only one of the side surfaces.

2( b ) and FIG. 2( c ) 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, respectively. The end mills 102 and 103 of the illustrated example are further formed with embedded Surface 28. The embedded surface 28 is a flat surface on which the embedded portion 24 is formed. The embedded surface 28 is typically formed in a direction intersecting the extending direction of the reference plane. The embedding surface 28, for example, may be formed by extending in a direction perpendicular to the extending direction of the reference plane as shown in FIG. By forming the embedded surface 28, the embedded part 24 can be formed on the flat surface, so the formation of the embedded part and the embedding of the cutting blade into the embedded part become easy. Furthermore, by adopting the structure shown in FIG. 2( c), as long as the embedding portion 24 extending in a direction perpendicular to the embedding surface 28 is formed, and the cutting blade 10 is embedded in a manner perpendicular to the embedding surface 28, the desired bevel angle can be automatically realized. Therefore, the embedding of the cutting blade into the embedding portion becomes very easy, and the setting of the bevel angle of the cutting blade becomes very easy.

Fig. 2(d) is a schematic plan view viewed from the axial direction for explaining the structure of an end mill according to another embodiment of the present invention. In the end mill 104 of the illustrated example, the upstream portion 20u of the main body 20 in the rotational direction R of the embedded portion 24 protrudes more than the downstream portion 20d when viewed from the rotational axis direction. With such a configuration, cutting chips can be discharged more favorably. The depth d1 on the upstream side of the embedded portion in the direction of rotation is preferably 0.50 mm to 1.50 mm, more preferably 0.50 mm to 1.00 mm. The depth d2 on the downstream side of the embedded portion in the direction of rotation is preferably 0.30 mm to 1.25 mm, more preferably 0.30 mm to 0.75 mm. If d1 and d2 are in such a range, while achieving the above-mentioned excellent chip discharge performance, the fixing strength of the cutting blade to the main body and the strength of the main body can be ensured. Both sides of its own strength. The ratio d1/d2 of d1 and d2 is preferably 1.20~1.67, more preferably 1.33~1.67. If the ratio d1/d2 is within such a range, there is an advantage that it becomes a structure that can more easily withstand the cutting conditions of the optical film processing of the stack.

The above-mentioned embodiments can be combined appropriately. For example, as shown in Figure 2 (e), it is also possible to combine the embodiment of Fig. 2 (d) with the embodiment of the oblique angle of 0°; it is also possible to combine the embodiment of Fig. 2 (a), Fig. 2 (b) or Fig. 2 (c) with the embodiment of the oblique angle of 0°. For another example, regarding the implementation form of Fig. 2 (a) ~ Fig. 2 (e), it is also possible to change the number of cutting blades into 3 pieces (3 embedded parts) respectively, or to change the number of cutting blades into 4 or more pieces (the embedded parts are more than 4 places) respectively. It goes without saying that suitable combinations other than those shown in the examples of the above-mentioned embodiments are also included in the present invention.

B. Manufacturing method of end mill

The manufacturing method of the end mill described in item A above includes the steps of: embedding the cutting blade 10 in the embedding portion 24 of the main body 20; Hereinafter, it will be briefly described.

First, make the body. The main body can be produced by, for example, processing a sintered body obtained by a well-known powder metallurgy method into a cylindrical shape by a well-known method in the industry. Next, an embedded portion is formed in the main body. The embedded part may be formed by any appropriate method. Specific examples of the forming method include laser processing and dicing processing. On the other hand, make the cutting blade. When making a cutting blade with a base made of superhard material and a sintered diamond layer on one side of the base, The cutting blade can be manufactured by the following process: first, cutting out a predetermined shape of the cutting blade forming sheet from the base material having the base and the sintered diamond layer. Cutting out is performed, for example, by electrical discharge machining or laser machining. Next, the base portion of the obtained cutting blade forming sheet is cut to reduce the thickness to a predetermined thickness, whereby a cutting blade is obtained. When the cutting blade is made 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 (typically, the cutting blade is inserted into the embedded portion) in the embedded portion formed as described above. Finally, in a state where the cutting blade is embedded in the embedded part, the cutting blade is fixed to the embedded part. Specifically, the cutting blade can be fixed to the embedded part by vacuum brazing or high frequency brazing. Even for cutting blades containing sintered diamonds, vacuum brazing can well fix them to the main body (embedded part). This is because, since the residual oxygen and moisture during brazing can be removed, the oxide film on the surface of the main body can be destroyed and regeneration of the oxide film can be prevented, so the wettability of the surface of the main body can be increased. High frequency brazing can be processed at low temperature. 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 diamonds, the sintered diamond is fixed to the main body (embedded part).

C. How to use the end mill

The end mills described in the above items A and B are typically suitable for use in a method of manufacturing 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 laminates in which these are appropriately laminated according to purposes (such as circular polarizing plates for anti-reflection, polarizing plates with conductive layers for touch panels). In one embodiment, the optical film contains an adhesive layer (for example, an adhesive layer, an adhesive layer). By using the end mill according to the embodiment of the present invention, even an optical film including an adhesive layer can suppress adhesive shortage caused by dicing.

Hereinafter, the manufacturing method in the case of using the polarizing plate with an adhesive layer as an example of an optical film is demonstrated. Specifically, each step of a method of manufacturing a polarizing plate having a planar shape with an adhesive layer as shown in FIG. 3 will be described. In addition, it is obvious to the operators that the optical film is not limited to the polarizing plate with the adhesive layer, and the planar shape of the polarizing plate with the adhesive layer is not limited to the planar shape in FIG. 3 . That is, the end mill according to the embodiment of the present invention can be applied to a method of manufacturing any optical film of any shape.

C-1. Formation of workpiece

FIG. 4 is a schematic perspective view for explaining dicing of an optical film, and a workpiece 200 is shown in this figure. As shown in FIG. 4 , a workpiece 200 in which a plurality of optical films (polarizing plates with adhesive layers) are stacked is formed. Since the polarizing plate with the adhesive layer can be manufactured by a well-known method in the industry, the detailed description of the manufacturing method is omitted. Typically, the polarizing plate with the adhesive layer is cut into any appropriate shape when the workpiece is formed. Specifically, the polarizing plate with the adhesive layer can be cut into a rectangular shape, or can be Therefore, the shape that has been cut into a similar rectangular shape can also be cut into a suitable shape (such as a circle) corresponding to the purpose. In the illustrated example, the polarizing plate with the adhesive layer is 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 orthogonal to these. The workpiece 200 is preferably clamped from top to bottom by a clamping means (not shown). The total thickness of the workpiece is preferably 10 mm to 50 mm, more preferably 15 mm to 25 mm, more preferably about 20 mm. Such a thickness can prevent damage caused by the compression of the clamping means or the impact during cutting. The polarizing plates with the adhesive layer are overlapped in such a way that the workpiece has such a total thickness. The number of polarizers constituting the adhesive layer of the workpiece may be, for example, 20 to 100. The clamping means (eg jig) can be made of soft material or hard material. When it is made of soft material, its hardness (JIS A) is preferably 60°~80°. If the hardness is too high, the indentation caused by the clamping means may remain. If the hardness is too low, the position may be shifted due to the deformation of the jig, and the cutting accuracy will become insufficient.

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 . Typically, the end mill 100 is used by being held by a machine tool (not shown), rotated at a high speed around the rotation axis of the end mill, feeding in a direction intersecting the rotation axis, and cutting the cutting blade against the outer peripheral surface of the workpiece 200 . That is, cutting is typically performed by bringing the cutting edge of the end mill into contact with the outer peripheral surface of the workpiece 200 . When making a polarizing plate with an adhesive layer in a top view as shown in FIG. 3 , chamfers 200E, 200E, In 200F, 200G, and 200H, a recessed portion 200I is formed in the central portion of the outer peripheral surface connecting the chamfered portions 200E and 200H.

The cutting process of the workpiece 200 will be described in detail. First, as shown in FIG. 5( a), chamfering is performed on the part where the chamfered portion 200E of FIG. 2 is to be formed, and then, as shown in FIGS. Finally, as shown in FIG. 5( e ), the concave portion 200I is formed by cutting. In addition, although the chamfered part 200E, 200F, 200G, 200H, and the recessed part 200I are formed in this order in the example shown in the figure, they should just be formed in arbitrary appropriate order.

The conditions of the cutting process can be appropriately set in accordance with the configuration, desired shape, and the like of the polarizing plate with the adhesive layer attached. For example, the rotational speed (number of rotations) of the end mill is preferably less than 25000 rpm, more preferably less than 22000 rpm, and still more preferably less than 20000 rpm. The lower limit of the rotation speed of the end mill may be, for example, 10000 rpm. Also, for example, the feed rate of the end mill should be 500 mm/min to 10000 mm/min, more preferably 500 mm/min to 2500 mm/min, more preferably 800 mm/min to 1500 mm/min. Also, for example, the cutting amount of the end mill is preferably 0.8 mm or less, more preferably 0.3 mm or less. The number of cuts performed on the cut portion by the end mill may be 1 time, 2 times, 3 times or more.

As mentioned above, using the end mill of embodiment of this invention, the polarizing plate with the adhesive layer which was cut and processed was obtained. In the example shown in the figure, a polarizing plate having an adhesive layer attached to a portion subjected to non-linear processing was obtained.

Industrial availability

The end mill of the present invention is suitable for cutting optical films cutting processing. The optical film cut and processed by the end mill of the present invention can be used in a special-shaped image display part represented by, for example, an instrument panel of a car and a smart watch.

10: Cutting blade

10a: blade tip

10b: Bevel

10c: Clearance surface

11: base

12: Sintered diamond layer

20: subject

22: Rotation axis

24: Embedded part

30: chip hole

100: end mill

200: workpiece

d: depth

E: Extension line of cutting blade

R: direction of rotation

α: Bevel

β: clearance angle

γ: blade tip angle

Claims (8)

An end mill comprising: a main body provided with a plurality of embedded parts and rotating around a rotating shaft; and a plurality of cutting blades respectively embedded in the plurality of embedded parts and fixed as the outermost diameter, the cutting blades are composed of sintered diamond, the helix angle of the cutting blades is 0°, and the outer diameter is less than 10 mm, and the cutting blades are embedded in the embedded parts so that the extension line of the cutting blades does not pass through the rotating shaft and defines a bevel angle of a predetermined angle. Fixing, forming a reference plane on the body, the reference plane extending in a direction forming the predetermined angle with respect to the extending direction of the cutting blade, and forming a planar embedding surface on the main body, the planar embedding surface extending in a direction forming the predetermined angle relative to the direction perpendicular to the extending direction of the reference plane, and the cutting blade is embedded in the embedding portion in a manner perpendicular to the embedding surface and fixed. The end mill according to claim 1, wherein the body is such that a part on the upstream side of the embedded part in the direction of rotation when viewed from the direction of the rotation axis protrudes outward from the embedded surface more than a part on the downstream side of the embedded part in the direction of rotation. The end milling cutter according to claim 1 or 2, wherein the cutting edge has a base made of superhard material, and a sintered diamond layer provided on one side of the base. The end milling cutter according to claim 1 or 2, wherein the depth of the embedded part is 0.30mm~1.50mm. The end milling cutter according to claim 1 or 2, wherein the plurality of embedded parts are arranged at symmetrical positions with respect to the rotation axis. A manufacturing method is the manufacturing method of the end mill according to any one of claims 1 to 5, comprising 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 in the state of embedding the cutting blade in the embedding portion. The manufacturing method according to claim 6, wherein the cutting blade has a base made of 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 part by vacuum brazing or high-frequency brazing. The manufacturing method according to claim 6, wherein the cutting blade is made of sintered diamond, and the sintered diamond is fixed to the embedded part by vacuum brazing in the manufacturing method.