Composite cutting tool

Abstract

Provided are a composite cutting tool capable of cutting even a thick workpiece without failure, and a method capable of efficiently and easily manufacturing a resin sheet using such a composite cutting tool. A composite cutting tool according to an embodiment of the present invention is provided with: a main body that rotates about a rotation axis; a cutting edge provided on the outer periphery of the main body, the cutting edge having a cutting edge, a rake face, and a flank face; and a grinding part which has a file-shaped surface and is provided as a protruding part integrally formed with the main body on a part of the flank of the cutting edge.

Description

[0001] This application is a divisional application of a Chinese patent application with an application date of January 5, 2023, an application number of "202310013807.8", and a title of "Composite Cutting Tool and Method for Manufacturing Resin Sheet Using the Same". Technical Field

[0002] The present invention relates to a composite cutting tool and a method for manufacturing a resin sheet using the same. Background Art

[0003] Various resin sheets corresponding to uses are widely used. After the resin sheet is cut into a specified shape, the outer peripheral end face is sometimes subjected to finish machining. In such finish machining, cutting by an end mill is sometimes performed. Cutting by an end mill is generally performed on a workpiece in which multiple resin sheets are overlapped. Here, considering manufacturing efficiency, it is preferable to cut a thick workpiece. However, in the case of cutting a thick workpiece, if the end mill is inclined, there may be a portion where the end mill does not contact the workpiece. Therefore, there is a problem that the holding state of the end mill on the machine tool must be precisely adjusted and the thickness of the workpiece has to be made below a certain value, resulting in insufficient manufacturing efficiency.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Laid-Open No. 2009-196015 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] The present invention is proposed to solve the above-mentioned prior problems, and its main object is to provide a composite cutting tool that can cut even a thick workpiece without trouble, and a method for manufacturing a resin sheet that can be manufactured efficiently and simply using such a composite cutting tool.

[0009] Means for Solving the Problems

[0010] The composite cutting tool of the technical solution of the present invention has: a main body that rotates around a rotation axis; a cutting edge provided on the outer peripheral portion of the main body, having a tool tip, a rake face, and a flank face; and a grinding portion having a file-like surface, provided as a protruding portion integrally formed with the main body on a part of the flank face of the cutting edge.

[0011] In one technical solution, the grinding portion is configured such that the file-like surface rotates along a circular orbit.

[0012] In one technical solution, the uneven depth D of the file-like surface is 1 μm to 120 μm, and the pitch p of the unevenness is 1 μm to 250 μm.

[0013] In one technical solution, the surface roughness of the file-like surface is, as the number of the file edge, #60 or more and #2000 or less.

[0014] The composite cutting tool of the technical solution of the present invention has: a main body that rotates around a rotation axis; a cutting edge provided on the outer peripheral portion of the main body, having a tool tip, a rake face, and a flank face; and a grinding portion provided as a protruding portion having a file-like surface on a part of the flank face of the cutting edge.

[0015] In one technical solution, the protruding height H of the grinding portion is 0.1 μm to 150 μm. Here, the protruding height H is represented by H = R2 - R1, where R1 is the distance from the rotation axis to the tool tip, and R2 is the distance from the rotation axis to the surface of the protruding portion.

[0016] In one technical solution, the distance L from the tool tip to the wall surface of the grinding portion in the rotational direction and the R1 satisfy the following formula (1):

[0017] L ≥ 0.1 × R1…(1).

[0018] In one technical solution, the cutting residual height Ph per pitch of the composite cutting tool is 0.03 μm to 280 μm. Here, the pitch P is represented by the following formula (2), and the cutting residual height Ph per pitch is represented by the following formula (3):

[0019] P = F / (S × N)…(2)

[0020] Ph = arcsin(P / 2 × R1)…(3)

[0021] In formula (2), F is the feed rate (mm / minute) of the composite cutting tool, S is the rotational speed (rpm) of the composite cutting tool, and N is the number of cutting edges of the composite cutting tool.

[0022] In one technical solution, the grinding portion contains diamond particles.

[0023] In one technical solution, the rake angle θ1 of the composite cutting tool is -30° to 45°, and the tool tip angle θ2 is 20° to 100°. Here, the rake angle is the angle formed by the straight line connecting the rotation axis and the tool tip and the straight line extending along the rake face from the tool tip in a cross section in the direction orthogonal to the rotation axis; the tool tip angle is the angle formed by the straight line extending along the rake face from the tool tip and the straight line extending along the flank face from the tool tip in this cross section orthogonal to the rotation axis.

[0024] According to another technical solution of the present invention, a method for manufacturing a resin sheet is provided. The manufacturing method includes: overlapping multiple resin sheets to form a workpiece; and cutting the outer peripheral surface of the workpiece with the composite cutting tool described above.

[0025] In one technical solution, the thickness of the workpiece is 30 mm or more.

[0026] In one technical solution, the resin sheet includes an adhesive layer and / or an adhesive layer.

[0027] In one technical solution, the resin sheet includes an optical film.

[0028] In one technical solution, the optical film includes a polarizer.

[0029] Advantages of the Invention

[0030] According to the embodiments of the present invention, a composite cutting tool capable of cutting even a thick workpiece without failure can be realized. By using such a composite cutting tool, a method for manufacturing a resin sheet with high efficiency and simplicity can be realized. Description of the Drawings

[0031] Figure 1A It is a schematic top view when observing the composite cutting tool according to one embodiment of the present invention from the direction of the rotation axis.

[0032] Figure 1B It is Figure 1A a schematic perspective view of the composite cutting tool.

[0033] Figure 2 It is a schematic top view of the main part showing the detailed structure of the composite cutting tool according to one embodiment of the present invention.

[0034] Figure 3 It is a schematic cross-sectional view of the main part for explaining the uneven depth and pitch of the surface of the grinding part of the composite cutting tool according to one embodiment of the present invention.

[0035] Figure 4 (a) to Figure 4 (e) are respectively schematic top views of the main part showing modified examples of the grinding part of the composite cutting tool according to the embodiments of the present invention.

[0036] Figure 5 It is a schematic perspective view for explaining the outline of the end face processing of the resin sheet in the manufacturing method according to the embodiment of the present invention.

[0037] Figure 6 (a) and Figure 6 (b) are schematic top views for explaining an example of the end face processing in the case where the resin sheet includes a polarizer in the manufacturing method according to the embodiment of the present invention. Detailed Embodiments

[0038] Hereinafter, the specific embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to these embodiments. In addition, the accompanying drawings are schematically shown for easy observation, and the ratios of length, width, thickness, and angles in the drawings are different from the actual ones. Furthermore, in order to make the detailed shapes and the meanings of the reference numerals in the drawings easy to understand, the shapes may not be correctly corresponded between the drawings sometimes.

[0039] A. Composite Cutting Tool

[0040] Figure 1A is a schematic top view when observing a composite cutting tool according to an embodiment of the present invention from the direction of the rotation axis; Figure 1B is Figure 1A a schematic perspective view of the composite cutting tool. The illustrated composite cutting tool 20 has: a main body 22 that rotates about a rotation axis 21; a cutting edge 23 provided on the outer peripheral portion of the main body 22, having a cutting tip 23a, a rake face 23b, and a flank face 23c; and a grinding portion 24 provided as a protruding portion having a file-like surface on a part of the flank face of the cutting edge 23.

[0041] The composite cutting tool 20 is integrally formed of a hard metal material such as cemented carbide or high-speed tool steel, and has a substantially cylindrical shaft shape centered on the rotation axis 21. In the illustrated composite cutting tool, one end portion (the upper end portion in the illustration) where the cutting edge is not formed is provided as a still cylindrical shank portion 25. It is also possible to provide shank portions at both end portions of the composite cutting tool. The shank portion 25 of the composite cutting tool is held by the spindle of a machine tool such as a machining center, and the object is cut by bringing the cutting edge into contact with the object by rotating it about the rotation axis 21. In the case where one end portion is provided as a shank portion, the composite cutting tool is held by the machine tool in a cantilever state; in the case where both end portions are provided as shank portions, the composite cutting tool is held by the machine tool in a double-supported state.

[0042] The cutting edge 23 is provided on the outer peripheral portion of the main body 22 as described above. The cutting edge 23 has a cutting tip 23a, a rake face 23b, and a flank face 23c. The rake face 23b is the wall surface of the cutting edge 23 facing the rotation direction T. In the cross section in the direction orthogonal to the rotation axis in the illustrated example, the rake face 23b extends in such a manner that while defining an arc recessed toward the side opposite to the rotation direction T on one side, it faces the side opposite to the rotation direction T as it goes toward the outer peripheral side. The flank face 23c is the outer peripheral surface of the cutting edge 23 and intersects the rake face 23b to define the cutting tip 23a. The flank face 23c is also substantially the outer peripheral surface of the composite cutting tool 20. It is preferable to roughen the flank face 23c. As the roughening treatment, any appropriate treatment can be adopted. As a representative example, shot peening can be cited. By performing the roughening treatment on the flank face, adhesion of the adhesive and / or binder to the cutting edge is suppressed in the case where the object to be cut (typically a resin sheet) includes an adhesive layer and / or a bonding agent layer, and as a result, blocking can be suppressed. In the present specification, "blocking" refers to the phenomenon in which resin sheets at the workpiece are bonded to each other by an adhesive or the like on the end face in the case where the resin sheet includes an adhesive layer and / or a bonding agent layer, and the cutting chips of the adhesive or the like adhering to the end face exacerbate the bonding between the resin sheets.

[0043] As the number of cutting edges (the number of edges of the composite cutting tool), any appropriate number of edges can be adopted according to the purpose. The number of edges can be 1, 2, 3, 4 as in the illustrated example, or 5 or more. Preferably, the number of edges is 2 or 4. With such a structure, the rigidity of the edge can be ensured and a groove can be ensured to enable good discharge of the cutting chips. In the case where the number of edges is plural (2 or more), the plurality of cutting edges can be formed at equal intervals in the circumferential direction as in the illustrated example, or can be formed at unequal intervals in the circumferential direction (not illustrated). Further, in the case where the number of edges is plural (2 or more), typically, the rotation trajectories of the plurality of cutting edges around the rotation axis 21 coincide with each other.

[0044] Depending on the purpose, the helix angle Θ of the cutting edge can be 0° or can have a specific helix angle. That is, depending on the purpose, the cutting edge can be a straight edge or a helical edge. The helix angle Θ of the cutting edge can be, for example, 0° to 65°, can be, for example, 10° to 55°, can be, for example, 20° to 50°, or can be, for example, 30° to 45°. In addition, in the present specification, "the helix angle is 0°" means that the cutting tip 23a extends in a direction substantially parallel to the rotation axis 21. In addition, "0°" means substantially 0°, and also includes the case where a slight angle is twisted due to machining errors or the like.

[0045] Figure 2 It is a schematic top view of the main part showing the detailed structure of the composite cutting tool 20. AsFigure 2 As shown, the rake angle θ1 of the cutting edge is preferably -30° to 45°, more preferably -10° to 30°, and even more preferably 0° to 20°; the nose angle θ2 is preferably 20° to 100°, more preferably 30° to 90°, and even more preferably 45° to 80°. If the rake angle θ1 and the nose angle θ2 of the cutting edge are within such ranges, the machined surface obtained by the cutting edge is smoothed, so there is an advantage that the subsequent machining by the grinding portion is further homogenized. In this specification, the "rake angle" is the angle formed by the straight line connecting the rotation axis 21 and the tool tip 23a and the straight line extending along the rake face 23b from the tool tip 23a in a cross-section in the direction orthogonal to the rotation axis; the "nose angle" is the angle formed by the straight line extending along the rake face 23b from the tool tip 23a and the straight line extending along the flank face 23c from the tool tip 23a in a cross-section in the direction orthogonal to the rotation axis. In addition, when the rake face is defined by an arc in a cross-section in the direction orthogonal to the rotation axis as shown in the figure, the line extending along the rake face is the tangent of the rake face extending from the tool tip. Furthermore, the flank face is the outer peripheral surface of the cutting edge and is defined by an arc in a cross-section in the direction orthogonal to the rotation axis, so the line extending along the flank face is substantially the tangent of the flank face extending from the tool tip. Further, a negative (-: minus) rake angle means that in a cross-section in the direction orthogonal to the rotation axis, the straight line extending along the rake face from the tool tip is on the rotation direction T side ( Figure 2 the left side) of the straight line connecting the rotation axis and the tool tip.

[0046] In an embodiment of the present invention, as described above, a grinding portion 24 is formed on a part of the flank face 23c. The grinding portion 24 is provided as a protruding portion having a file-like surface. The grinding portion 24 (substantially its surface) typically contains diamond particles. If it has such a structure, a file-like surface with appropriate surface roughness and surface hardness can be formed. The grinding portion 24 can typically function as a rotary grindstone. In the case where a plurality of cutting edges are provided, the grinding portion is typically provided on each cutting edge. That is, typically, the number of cutting edges is the same as the number of grinding portions. Further, the grinding portion is typically provided at a corresponding position of each cutting edge. In addition, in the case where a plurality of grinding portions are formed, the plurality of grinding portions, like the case of the cutting edges, typically have the same rotation trajectory around the rotation axis 21.

[0047] The protruding height H of the grinding portion 24 is preferably from 0.1 μm to 100 μm, more preferably from 1 μm to 50 μm, and even more preferably from 5 μm to 30 μm. If the protruding height H of the grinding portion is within such a range, there is an advantage that the resin sheet does not melt or break in the processed surface formed by the grinding portion, and a uniform processed surface can be obtained. Here, the protruding height H of the grinding portion is represented by H = R2 - R1. R1 is the distance from the rotation axis 21 to the cutting edge tip 23a, and R2 is the distance from the rotation axis 21 to the surface of the grinding portion (protruding portion) 24. R1 is the radius of the rotation orbit of the cutting edge 23, and R2 is also the radius of the rotation orbit of the grinding portion 24. Therefore, the protruding height H of the grinding portion is the difference between the rotation radius of the grinding portion and the rotation radius of the cutting edge. In the cross-section of the grinding portion in the direction orthogonal to the rotation axis in the illustrated example, the wall surfaces on both sides of the grinding portion may extend radially with respect to the rotation axis, or may extend outward in a manner substantially orthogonal to the outer periphery (flank face) of the cutting edge. Further, in the cross-section of the grinding portion in the direction orthogonal to the rotation axis in the illustrated example, the surface of the grinding portion is substantially flat and substantially coincides with the rotation orbit of the grinding portion.

[0048] The width W (mm) of the grinding portion 24 in the circumferential direction of the composite cutting tool 20 is preferably equal to or less than R1 (mm), more preferably equal to or less than 0.5 × R1 (mm), and even more preferably equal to or less than 0.3 × R1 (mm). The lower limit of the width W of the grinding portion can be, for example, 0.01 × R1 (mm). If the width W of the grinding portion is within such a range, there is an advantage that there is less clogging of the cutting chips in the grinding portion, and the processing quality can be maintained constant for a long time. In other words, by adjusting the width of the grinding portion according to the outer diameter of the composite cutting tool, the above-mentioned advantage can be obtained.

[0049] The position where the grinding portion 24 is provided on the flank face 23c of the cutting edge 23 can be appropriately set according to the purpose. In one embodiment, the distance L (mm) from the cutting edge tip 23a to the wall surface of the grinding portion 24 facing the rotation direction and the distance R1 (mm) from the rotation axis 21 to the cutting edge tip 23a satisfy the following formula (1):

[0050] L ≥ 0.1 × R1…(1).

[0051] The distance L is preferably from 0.1 × R1 to 1.0 × R1, more preferably from 0.15 × R1 to 0.8 × R1. If the distance L and the distance R1 are in such a relationship, there is an advantage that there is less accumulation of cutting chips on the surface of the grinding portion, and the processing quality can be maintained constant for a long time. In other words, by defining the position of the grinding portion in such a relationship according to the outer diameter of the composite cutting tool, the above-mentioned advantage can be obtained.

[0052] The surface roughness of the surface of the grinding part 24, as the number of file teeth, is preferably #60 or more, more preferably #100 or more, and even more preferably #200 or more. As the number of file teeth, the surface roughness is preferably #2000 or less, more preferably #1200 or less, and even more preferably #800 or less. If the surface roughness of the grinding part is within such a range, there are advantages that the resin sheet will not melt or break in the machined surface obtained by the grinding part, and the clogging of cutting chips into the grinding part is less, and the machining quality can be maintained constant for a long time. In addition, for the number of file teeth, the smaller the number, the coarser the abrasive grain gap. The number can be adjusted by the amount, size, etc. of diamond particles.

[0053] Figure 3 It is a main part schematic cross-sectional view for explaining the uneven shape of the file-like surface of the grinding part 24. The depth D of the unevenness of the file-like surface of the grinding part 24 is, for example, 1 μm to 120 μm. The lower limit of the depth D is preferably 5 μm or more, more preferably 10 μm or more. The upper limit of the depth D is preferably 50 μm or less, more preferably 35 μm or less. The pitch p of the unevenness of the file-like surface of the grinding part 24 is, for example, 1 μm to 250 μm. The lower limit of the pitch p of the unevenness is preferably 5 μm or more, more preferably 10 μm or more. The upper limit of the pitch p of the unevenness is preferably 100 μm or less, more preferably 60 μm or less. If the uneven shape of the grinding part surface has such a structure, there are advantages that the resin sheet will not melt or break in the machined surface obtained by the grinding part, and the clogging of cutting chips into the grinding part is less, and the machining quality can be maintained constant for a long time.

[0054] The outer diameter of the composite cutting tool can be appropriately set according to the purpose. More specifically, the outer diameter of the composite cutting tool is preferably 0.5 mm to 30 mm, more preferably 0.8 mm to 25 mm, and even more preferably 1 mm to 20 mm. If the outer diameter of the composite cutting tool is within such a range, machining can be carried out without trouble using a machine tool capable of general end mill machining. In addition, the outer diameter of the composite cutting tool is a value obtained by multiplying the R2 by 2 times (that is, the diameter of the rotation orbit of the grinding part).

[0055] In one embodiment, the cutting residual height Ph per pitch of the composite cutting tool is preferably 0.03 μm to 280 μm, more preferably 0.1 μm to 100 μm, and even more preferably 0.2 μm to 10 μm. If the cutting residual height Ph is within such a range, the resin sheet will not melt or break in the machined surface obtained by the grinding part, and there is an advantage that a uniform machined surface can be obtained. Here, the pitch P is represented by the following formula (2), and the cutting residual height Ph per pitch is represented by the following formula (3):

[0056] P = F / (S×N)…(2)

[0057] Ph = arcsin(P / 2×R1)…(3)

[0058] In Equation (2), F is the feed rate (mm / minute) of the composite cutting tool, S is the rotational speed (rpm) of the composite cutting tool, and N is the number of cutting edges of the composite cutting tool.

[0059] The shape of the grinding portion 24 (defining the outer contour shape of the surface of the grinding portion) as viewed from the direction of the rotation axis can be any suitable shape according to the purpose and the like. Figure 4 (a) to Figure 4 (e) are schematic top views of the main parts showing representative modified examples of the grinding portion, respectively. Figure 4 In the cross-section of the grinding portion of (a) in the direction orthogonal to the rotation axis, there is a substantially flat surface along the outer circumference from the wall surface facing the side opposite to the rotation direction to a specified portion in the rotation direction, and the protruding height gradually decreases as it goes from this specified portion to the wall surface facing the rotation direction. Figure 4 In the cross-section of the grinding portion of (b) in the direction orthogonal to the rotation axis, the protruding height gradually decreases as it goes from the wall surface facing the side opposite to the rotation direction to the wall surface facing the rotation direction. Figure 4 In the cross-section of the grinding portion of (c) in the direction orthogonal to the rotation axis, the protruding height gradually decreases at a first inclination angle from the wall surface facing the side opposite to the rotation direction to a specified portion in the rotation direction, and the protruding height gradually decreases at a second inclination angle larger than the first inclination angle as it goes from this specified portion to the wall surface facing the rotation direction. Figure 4 In the cross-section of the grinding portion of (d) in the direction orthogonal to the rotation axis, the wall surface facing the rotation direction extends in such a way that it faces the side opposite to the rotation direction as it faces the outside (protruding side). Figure 4 In the cross-section of the grinding portion of (e) in the direction orthogonal to the rotation axis, the intersection of the line defining the surface of the grinding portion and the line defining the wall surface facing the rotation direction has a chamfered shape. These modified examples can also be appropriately combined. For example, in Figure 4 (a) to Figure 4 In the modified examples of (d), the intersection of the line defining the surface of the grinding portion and the line defining the wall surface facing the rotation direction can also have a chamfered shape; in addition, for example, in Figure 4 (a) to Figure 4 In the modified examples of (c), the wall surface facing the rotation direction can also extend in such a way that it faces the side opposite to the rotation direction as it faces the outside (protruding side). These modified examples can be appropriately selected according to the protruding height H of the grinding portion, the position (distance L) where the grinding portion is provided, the cutting residual height Ph, etc. For example, Figure 4 The modified example of (b) may be useful when the protruding height H of the grinding portion is large; Figure 4(c)'s modified example may be useful when the distance L is large; Figure 4 (d)'s modified example may be useful when the cutting residual height Ph is small; Figure 4 (e)'s modified example may be useful when the cutting residual height Ph is large. In addition, Figure 4 (a)'s modified example may be useful when the protrusion height H, the distance L, and the cutting residual height Ph are all of medium size.

[0060] B. Resin sheet

[0061] As the resin sheet, any suitable resin sheet that can be provided for end face processing can be cited. The resin sheet can be either a film composed of a single layer or a laminate. As specific examples of the resin sheet, an optical film, a heat insulating sheet, a resin window, a surface protective film, a fiber reinforced plastic (FRP) sheet, a packaging film, and a food film can be cited. In one embodiment, the resin sheet includes an optical film. Since the optical film requires precise end face processing compared to other resin sheets or films, the effects of the embodiments of the present invention become significant. As specific examples of the optical film, a polarizing plate, a retardation film, a polarizing panel (typically a laminate of a polarizing plate and a protective film), a conductive film for a touch panel, a surface treatment film, and a laminate obtained by appropriately laminating them according to the purpose (for example, a circular polarizing plate for antireflection, a polarizing plate with a conductive layer for a touch panel) can be cited. In one embodiment, the resin sheet includes an adhesive layer and / or an adhesive layer. Therefore, the resin sheet can be, for example, an optical film including an adhesive layer and / or an adhesive layer. In the optical film including an adhesive layer and / or an adhesive layer, the effects of the embodiments of the present invention are more significant.

[0062] C. Manufacturing method of resin sheet

[0063] Hereinafter, a manufacturing method in the case of using a polarizing plate with an adhesive layer as an example of the resin sheet will be described. For those skilled in the art, it is obvious that the top view shape of the polarizing plate with an adhesive layer is not limited to the top view shape shown in the figure. In addition, for those skilled in the art, it is also obvious that the embodiments of the present invention can be applied to any suitable resin sheet other than the polarizing plate with an adhesive layer. That is, the embodiments of the present invention can be used for manufacturing any suitable resin sheet having any suitable shape.

[0064] C-1. Formation of workpiece

[0065] Figure 5 is a schematic perspective view for explaining the outline of the end face processing of the resin sheet (here, a polarizing plate with an adhesive layer) in the manufacturing method of the embodiment of the present invention. The workpiece W is shown in this figure. As Figure 5As shown, a workpiece W is formed by overlapping multiple polarizing plates with an adhesive layer. Typically, when forming the workpiece, the polarizing plate with an adhesive layer is cut from a roll stock into any appropriate size and shape. Specifically, it can be cut into a rectangular shape, a shape similar to a rectangle, or an appropriate shape corresponding to the purpose (such as a circle). In the illustrated example, the polarizing plate with an adhesive layer is cut into a rectangular shape, and the workpiece W has opposing outer peripheral surfaces (cutting surfaces) 1a, 1b and outer peripheral surfaces (cutting surfaces) 1c, 1d orthogonal to them. The cutting is performed by any appropriate unit. Specific examples of the cutting unit include punching with a punching tool (such as a Thomson tool) and laser irradiation. In one embodiment, a release liner may be temporarily adhered to the surface of the adhesive layer of the polarizing plate with an adhesive layer, and / or a surface protective film may be temporarily adhered to the surface of the polarizing plate with an adhesive layer on the side opposite to the adhesive layer.

[0066] The total thickness of the workpiece is, for example, 3 mm or more, preferably 5 mm or more, more preferably 10 mm or more, even more preferably 30 mm or more, and particularly preferably 60 mm or more. According to an embodiment of the present invention, by using the composite cutting tool described in item A above, even such a thick workpiece can be cut (typically end face machining) without problems. As a result, a resin sheet (here, a polarizing plate with an adhesive layer) can be manufactured efficiently and simply. On the other hand, the total thickness of the workpiece is preferably 150 mm or less, more preferably 100 mm or less. The upper limit of the total thickness of the workpiece is mainly due to structural limitations of the machine tool. In addition, according to an embodiment of the present invention, the effect is significant when the workpiece is thick, but of course, it can be implemented without problems even when the workpiece has a normal thickness (e.g., 10 mm or less).

[0067] Preferably, the workpiece W is clamped from above and below by a clamp mechanism (not shown). The clamp mechanism (such as a jig) can be made of either a soft material or a hard material. When made of a soft material, its hardness (JIS A) is preferably 60° to 80°. If the hardness is too high, indentation residues may be left by the clamp mechanism. If the hardness is too low, positional deviation may occur due to deformation of the jig, and sometimes the cutting accuracy may be insufficient.

[0068] C - 2. End face machining by a composite cutting tool

[0069] Next, the specified position of the outer peripheral surface of the workpiece W is cut (end face processing) by the composite cutting tool 20. As a representative example, the composite cutting tool 20 is held by a working machine (not shown) so that it rotates at high speed around the rotating axis of the composite cutting tool, and is fed in a direction intersecting the rotating axis while the cutting edge is brought into contact with and cut into the outer peripheral surface of the workpiece W. That is, as a representative example, the cutting edge of the composite cutting tool is brought into contact with and cut into the outer peripheral surface of the workpiece W for cutting. Furthermore, according to an embodiment of the present invention, following the cutting in by the cutting edge, grinding (cutting) is performed by a grinding portion whose radius of the rotating track is larger than that of the cutting edge. By additionally performing cutting by such a grinding portion, even a thick workpiece can be end-face processed without trouble (in more detail, there is no cutting residue caused by the cutting edge not coming into contact with the workpiece, and the entire thickness direction of the workpiece is uniform). Furthermore, cracks of a polarizing plate (represented by a polarizer) with an adhesive layer, dirt and agglomeration of the cutting edge can be suppressed. In particular, the development of cracks over time can be well suppressed. In addition, when a release liner and / or a surface protective film is temporarily attached to a polarizing plate with an adhesive layer, their warping can be suppressed. Here, the dirty edge of the cutting edge refers to the phenomenon that the adhesive of the adhesive layer adheres to the cutting edge and the cutting performance (processing performance) exceeds the allowable range and decreases. Agglomeration is as described above.

[0070] The conditions for end surface processing performed by the composite cutting tool can be appropriately set according to the type of resin sheet, the desired shape, etc. For example, the rotation speed (rotation speed) of the composite cutting tool is preferably 100rpm to 50000rpm, more preferably 1000rpm to 30000rpm, and more preferably 2000rpm to 20000rpm. In addition, for example, the feed speed of the composite cutting tool is preferably 100mm / min to 5000mm / min, more preferably 200mm / min to 4000mm / min, and more preferably 300mm / min to 3000mm / min. If the rotation speed and feed speed of the composite cutting tool are in such a range, even a thick workpiece can be end surface processed without trouble. The number of cutting times of the end surface of the workpiece (resin sheet) performed by the composite cutting tool can be 1 cutting, 2 cuttings, 3 cuttings or more.

[0071] The composite cutting tool can be held in a cantilever state or a double-support state on the machine tool. By holding it in a cantilever state, the movement of the composite cutting tool in the plane and in the vertical direction becomes easy. As a result, in the case where non-linear cutting (machining) is required, such cutting becomes easy. In addition, in the case of a cantilever, the manufacture of the composite cutting tool is easy. On the other hand, by holding it in a double-support state, the vibration of the cutting surface (the unevenness when observing the cutting surface from the side) can be suppressed. Furthermore, by holding it in a double-support state, the stress acting on the cutting edge of the composite cutting tool during cutting can be reduced. As a result, the durability of the composite cutting tool can be improved, and thus, the stability and reliability of the end face machining performed by the composite cutting tool can be improved.

[0072] The end face machining of the resin sheet by the composite cutting tool can be performed on the entire outer peripheral surface of the resin sheet or on a part of the outer peripheral surface. In the case where the resin sheet includes a polarizing plate (for example, in the case where the resin sheet is a polarizing plate with an adhesive layer as shown in the figure), the end face machining by the composite cutting tool is preferably performed only in the absorption axis direction of the polarizing plate. Figure 6 (a) and Figure 6 (b) are schematic top views showing an example of the specific steps for explaining the end face machining of a resin sheet (here, a polarizing plate with an adhesive layer) including a polarizing plate. In the present embodiment, as a representative example, the polarizing plate with an adhesive layer is cut into a rectangular shape as shown in Figure 6 (a) such that the absorption axis A of the polarizing plate is in the short side direction.

[0073] Next, as shown in Figure 6(As shown in (a), end face machining of the short side is performed using an end mill. The end mill can adopt any appropriate structure according to the purpose and the type of the resin sheet including the polarizing plate. For example, the end mill can have the same structure as the composite cutting tool except that it does not have a grinding part, or it can have a completely different structure as a whole (for example, outer diameter, number of cutting edges, helix angle, rake angle, tip angle). The conditions for end face machining performed by the end mill can be appropriately set according to the purpose and the like. The outer diameter of the end mill can be, for example, 0.5 mm to 30 mm, and can also be, for example, 1 mm to 20 mm. The rotational speed (rpm) of the end mill can be, for example, 100 rpm to 50,000 rpm, and can also be, for example, 1000 rpm to 35,000 rpm, and can also be, for example, 2000 rpm to 20,000 rpm. In addition, the feed rate of the end mill can be, for example, 100 mm / minute to 5000 mm / minute, and can also be, for example, 300 mm / minute to 3000 mm / minute. The number of cutting passes for the end face of the short side of the workpiece (resin sheet including the polarizing plate, here a polarizing plate with an adhesive layer) performed by the end mill can be 1 cutting pass, 2 cutting passes, 3 cutting passes or more. The figure example schematically shows two cutting passes of rough machining and finish machining. The rough machining and the finish machining can be performed under the same conditions or under different conditions.)

[0074] Next, as Figure 6 (shown in (b), end face machining of the long side is performed using a composite cutting tool. The structure of the composite cutting tool is as described in item A above, and the conditions for end face machining performed by the composite cutting tool are as described above. By performing such end face machining, even for thick workpieces, end face machining can be performed without problems. Furthermore, cracks, edge fouling, and caking of the cutting edges of the polarizing plate (typically a polarizing sheet) with an adhesive layer can be suppressed. In addition, when a release liner and / or a surface protective film are temporarily adhered to the polarizing plate with an adhesive layer, their warping can be suppressed. In the case where the entire outer periphery of the polarizing plate with an adhesive layer is subjected to end face machining using an end mill, there are many cases where cutting residues occur because the cutting edge does not contact the workpiece. In the case where the entire outer periphery of the polarizing plate with an adhesive layer is subjected to end face machining using a composite cutting tool, the machined end face in the direction parallel to the absorption axis is afraid of the impact caused by thermal shock and sometimes cracks occur. However, in the case where the resin sheet does not contain a polarizing sheet, even when the entire outer periphery of the resin sheet is subjected to end face machining using a composite cutting tool, such problems do not substantially occur.)

[0075] [Examples]

[0076] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. The evaluation items in the examples are as follows.

[0077] (1) Crack

[0078] The polarizing plates with an adhesive layer obtained in the examples, comparative examples, and reference examples were pasted onto a glass plate (thickness 1.1 mm) via the adhesive layer as experimental specimens.

[0079] (1-1) Cracks caused by thermal shock test

[0080] The experimental specimens were subjected to a thermal shock test in which they were kept at -40°C for 30 minutes and then at 85°C for 30 minutes, and this cycle was repeated 300 times. The generation state of cracks after the experiment was observed with an optical microscope (magnification 5 times). Specifically, the number and length (μm) of the generated cracks were investigated and evaluated according to the following criteria.

[0081] A: The number is 10 or less, and the maximum length is 500 μm or less

[0082] B: The number is 10 or less, but the maximum length exceeds 500 μm

[0083] C: The number exceeds 10, and the maximum length exceeds 500 μm

[0084] (1-2) Cracks caused by heating test

[0085] The experimental specimens were subjected to a heating test at 105°C for 1000 hours and evaluated in the same manner as (1-1).

[0086] (2) Warping

[0087] The warping amounts of the surface protective film and the release liner of the polarizing plates with an adhesive layer obtained in the examples, comparative examples, and reference examples were measured with a magnifying glass or a microscope. The maximum warping amount of one workpiece was defined as the warping amount and evaluated according to the following criteria.

[0088] A: The warping amount is 300 μm or less

[0089] B: The warping amount exceeds 300 μm and is 500 μm or less

[0090] C: The warping amount exceeds 500 μm

[0091] (3) Edge contamination

[0092] The contamination state caused by the adhesive was observed on the cutting edges of the composite cutting tools after end face machining in the examples and on the cutting edges of the end mills after end face machining in the comparative examples and reference examples, and evaluated according to the following criteria.

[0093] A: Substantially no contamination was confirmed

[0094] B: Contamination was confirmed, but no problems occurred during processing.

[0095] C: Significant contamination was confirmed, and problems also occurred during processing.

[0096] (4) Caking

[0097] The states of the workpieces after end face machining of the examples, comparative examples, and reference examples were observed and evaluated according to the following criteria.

[0098] A: It is easy to separate from the workpiece into individual polarizing plates with an adhesive layer.

[0099] B: Although it is possible to separate from the workpiece into individual polarizing plates with an adhesive layer, the separation operation is difficult.

[0100] C: The workpiece completely becomes a block, and it is impossible to separate individual polarizing plates with an adhesive layer.

[0101] <Example 1>

[0102] By a conventional method, a polarizing plate with an adhesive layer having a structure of a surface protective film (60 μm) / cycloolefin protective film (47 μm) / polarizer (5 μm) / cycloolefin protective film (24 μm) / adhesive layer (20 μm) / release liner in this order from the visual side was produced. In addition, as the surface protective film, a surface protective film having a structure of a PET substrate (50 μm) / adhesive layer (10 μm) was used. The polarizing plate with an adhesive layer was die-cut into a size of 5.7 (about 140 mm in length and 65 mm in width). Here, die-cutting was performed such that the absorption axis direction of the polarizer was in the horizontal (short side direction). Multiple die-cut polarizing plates with an adhesive layer were overlapped to form a workpiece. The total thickness of the workpiece was 45 mm. While holding the obtained workpiece by a clamp (fixture), end face machining of the short side (the absorption axis direction of the polarizer) was performed with a vertical milling cutter. Specifically, a vertical milling cutter with an outer diameter of 9 mm, two cutting edges, and a helix angle of 45° was used, and each short side was subjected to two-pass end face machining including rough machining and finish machining. The cutting amount for rough machining was 0.2 mm, and the cutting amount for finish machining was 0.1 mm. In either rough machining or finish machining, the feed rate of the vertical milling cutter was 1000 mm / minute, and the rotational speed was 35000 rpm. Next, end face machining of the long side (the direction orthogonal to the absorption axis direction of the polarizer) was performed with the composite cutting tool according to the embodiment of the present invention. A composite cutting tool having a grinding portion with a protrusion height of 20 μm provided on the flank face of the cutting edge of the vertical milling cutter was used. The protruding surface of the grinding portion was a file shape (or rotary grindstone shape) including diamond particles. The distance L from the tip of the cutting edge to the wall surface of the grinding portion in the rotational direction was 0.9 mm, and it had a relationship of L = 0.167 × R1 with the distance R1 from the rotation axis to the tip. End face machining of the long side was performed twice under the same conditions. Specifically, the feed rate of the composite cutting tool was 1000 mm / minute, the rotational speed was 8000 rpm, and the cutting amount per pass was 0.1 mm. Thus, a polarizing plate with an adhesive layer was obtained. In end face machining, it was not necessary to precisely adjust the holding states of the vertical milling cutter and the composite cutting tool to the machine tool, and uniform cutting was achieved throughout the entire thickness direction of the workpiece. For the obtained polarizing plate with an adhesive layer, the evaluations (1) to (4) were performed. The results are shown in Table 1.

[0103] <Example 2>

[0104] A polarizing plate with an adhesive layer was obtained in the same manner as in Example 1 except that the thickness of the workpiece was set to 60 mm. In end face machining, it was not necessary to precisely adjust the holding states of the vertical milling cutter and the composite cutting tool to the machine tool, and uniform cutting was achieved throughout the entire thickness direction of the workpiece. For the obtained polarizing plate with an adhesive layer, the same evaluations as in Example 1 were performed. The results are shown in Table 1.

[0105] <Comparative Example 1>

[0106] For all edges (the entire outer periphery) of the workpiece formed in the same manner as in Example 1, only face milling was performed using a end mill. Specifically, the entire outer periphery of the workpiece was provided for two-pass face milling including roughing and finishing in one stroke. The conditions for roughing and finishing were the same as those in Example 1. Next, only the long edges were face-milled using a rotary grinding stone (#400). The rotational speed of the rotary grinding stone was 1000 rpm, and the feed rate was 500 mm / minute. Thus, a polarizing plate with an adhesive layer was obtained. In the face milling using the end mill, cutting defects occurred in a part of the workpiece (the upper or lower end portion in the thickness direction). The cutting defects were significant in the long edges. For the obtained polarizing plate with an adhesive layer, the same evaluation as in Example 1 was performed. The results are shown in Table 1.

[0107] <Reference Example 1>

[0108] A polarizing plate with an adhesive layer was obtained in the same manner as in Comparative Example 1, except that the thickness of the workpiece was set to 15 mm. No cutting defects were confirmed in the face milling. For the obtained polarizing plate with an adhesive layer, the same evaluation as in Example 1 was performed. The results are shown in Table 1.

[0109] [Table 1]

[0110]

[0111] <Evaluation>

[0112] As can be seen from Table 1, the composite cutting tool of the embodiment of the present invention can cut even thick workpieces without failure.

[0113] Industrial Applicability

[0114] The composite cutting tool according to the embodiment of the present invention can be suitably used for the manufacture of resin sheets (particularly, face milling during manufacture). The resin sheet can be, for example, an optical film.

[0115] Reference Signs Explanation

[0116] W Workpiece

[0117] 20 Composite cutting tool

[0118] 21 Rotating shaft

[0119] 22 Main body

[0120] 23 Cutting edge

[0121] 23a Tool tip

[0122] 23b Rake face

[0123] Rear flank after 23c

[0124] Grinding section 24

Claims

1. A composite cutting tool comprising: The main body rotates around the rotation axis; a cutting edge, disposed at the outer periphery of the body, having a cutting edge, a rake face, and a flank face; and A grinding portion having a file-like surface is provided as a protrusion formed integrally with the body at a part of the flank surface of the cutting edge.

2. The composite cutting tool according to claim 1, in, The grinding unit is configured to rotate while the file-shaped surface traces a circular orbit.

3. The composite cutting tool according to claim 2, in, The concavo-convex depth D of the file-like surface is 1 μm to 120 μm, and the pitch p of the concavo-convex is 1 μm to 250 μm.

4. The composite cutting tool according to claim 2, in, The surface roughness of the file-like surface is, as the number of the file edge, not less than #60 and not more than #2000.

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