Composite cutting tool and method for producing resin sheet using the same

Abstract

Provided are a composite cutting tool that can cut even a thick workpiece without trouble, and a method for efficiently and easily manufacturing a resin sheet using such a composite cutting tool. The composite cutting tool of an embodiment of the present invention comprises: a main body that rotates around a rotation axis; a cutting edge that is provided at the outer periphery of the main body and has a cutting edge, a front cutting face, and a back cutting face; and a grinding portion that is provided as a protrusion having a file-like surface on a part of the back cutting face of the cutting edge. The method for manufacturing a resin sheet of an embodiment of the present invention comprises: overlapping a plurality of resin sheets to form a workpiece; and cutting the outer periphery of the workpiece using the composite cutting tool.

Description

Technical Field

[0001] The present invention relates to a composite cutting tool and a method for producing a resin sheet using the same. Background Art

[0002] Various resin sheets corresponding to the uses are widely used. After the resin sheet is cut into a specified shape, the outer peripheral end surface is sometimes provided for finishing. In such finishing, cutting with an end mill is sometimes performed. Cutting with an end mill is usually performed on a workpiece in which multiple resin sheets are overlapped. Here, if manufacturing efficiency is considered, it is preferred to cut a thick workpiece. However, when cutting a thick workpiece, if the end mill is tilted, there is sometimes a part where the end mill does not abut against the workpiece. Therefore, there is a problem that the holding state of the end mill to the working machine must be precisely adjusted and the thickness of the workpiece has to be made below a certain value, and the manufacturing efficiency is insufficient.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2009-196015 Summary of the invention

[0006] Problems to be solved by the invention

[0007] The present invention has been made to solve the above-mentioned conventional problems, and its main object is to provide a composite cutting tool capable of smoothly cutting even a thick workpiece, and a method for efficiently and simply producing a resin sheet using such a composite cutting tool.

[0008] Means used to solve problems

[0009] The composite cutting tool of the technical solution of the present invention comprises: a main body, which rotates around a rotation axis; a cutting edge, which is arranged on the outer periphery of the main body and has a cutting edge, a front cutting surface and a back cutting surface; and a grinding portion, which is a protrusion with a file-like surface and is arranged on a part of the back cutting surface of the cutting edge.

[0010] In one technical solution, the protrusion height H of the grinding part is 0.1 μm to 150 μm. Here, the protrusion height H is represented by H=R2-R1, where R1 is the distance from the rotation axis to the blade tip, and R2 is the distance from the rotation axis to the surface of the protrusion.

[0011] In one technical solution, the distance L from the blade tip to the wall surface of the grinding portion in the rotation direction and the R1 satisfy the following formula (1):

[0012] L≥0.1×R1…(1).

[0013] In one technical solution, the cutting residual height Ph of each 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 of each pitch is represented by the following formula (3):

[0014] P=F / (S×N)…(2)

[0015] Ph=arcsin(P / 2×R1)…(3)

[0016] In formula (2), F is the feed speed (mm / min) of the composite cutting tool, S is the rotation speed (rpm) of the composite cutting tool, and N is the number of cutting edges of the composite cutting tool.

[0017] In one technical solution, the grinding portion includes diamond particles.

[0018] In one technical solution, the composite cutting tool has a rake angle θ1 of -30° to 45° and a tool tip angle θ2 of 20° to 100°. Here, the rake angle is the angle formed by a straight line connecting the rotation axis and the tool tip and a straight line extending from the tool tip along the rake face in a cross section in a direction perpendicular to the rotation axis; the tool tip angle is the angle formed by a straight line extending from the tool tip along the rake face and a straight line extending from the tool tip along the flank face in a cross section in a direction perpendicular to the rotation axis.

[0019] According to another technical solution of the present invention, there is provided a method for manufacturing a resin sheet, which comprises: overlapping a plurality of resin sheets to form a workpiece; and cutting the outer peripheral surface of the workpiece with the composite cutting tool.

[0020] In one technical solution, the thickness of the workpiece is greater than 30 mm.

[0021] In one embodiment, the resin sheet includes an adhesive layer and / or a pressure-sensitive adhesive layer.

[0022] In one technical solution, the resin sheet includes an optical film.

[0023] In one technical solution, the optical film includes a polarizer.

[0024] Effects of the Invention

[0025] According to the embodiment of the present invention, a composite cutting tool that can cut even a thick workpiece without any trouble can be realized. By using such a composite cutting tool, a method for manufacturing a resin sheet efficiently and simply can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1AThis is a schematic plan view of a composite cutting tool according to one embodiment of the present invention as viewed from the rotation axis direction.

[0027] Figure 1B yes Figure 1A A schematic three-dimensional diagram of a composite cutting tool.

[0028] Figure 2 This is a schematic plan view of main parts showing the detailed structure of a composite cutting tool according to one embodiment of the present invention.

[0029] Figure 3 This is a schematic cross-sectional view of a main part for explaining the depth and pitch of the concavo-convexity on the surface of the grinding portion of the composite cutting tool according to one embodiment of the present invention.

[0030] Figure 4 (a)~ Figure 4 (e) are main part schematic plan views showing modified examples of the grinding portion of the composite cutting tool according to the embodiment of the present invention.

[0031] Figure 5 This is a schematic perspective view for explaining the outline of the end surface processing of the resin sheet in the production method according to the embodiment of the present invention.

[0032] Figure 6 (a) and Figure 6 (b) is a schematic plan view for explaining an example of end surface processing when the resin sheet includes a polarizer in the manufacturing method according to the embodiment of the present invention. DETAILED DESCRIPTION

[0033] Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited to these embodiments. In addition, the drawings are schematically shown for easy viewing, and the ratios and angles of the length, width, thickness, etc. 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 correspond correctly between the drawings.

[0034] A. Composite cutting tools

[0035] Figure 1A This is a schematic top view of a composite cutting tool according to one embodiment of the present invention as viewed from the direction of the rotation axis; Figure 1B yes Figure 1A A schematic three-dimensional view of a composite cutting tool. The composite cutting tool 20 shown in the figure comprises: a main body 22 that rotates around a rotation axis 21; a cutting edge 23 that is provided at the outer periphery of the main body 22 and has a cutting edge 23a, a front cutting surface 23b, and a back cutting surface 23c; and a grinding portion 24 that is a protrusion having a file-like surface and is provided on a part of the back cutting surface of the cutting edge 23.

[0036] The composite cutting tool 20 is integrally formed of a hard metal material such as cemented carbide and high-speed tool steel, and is in the shape of a roughly cylindrical shaft centered on the rotating shaft 21. In the composite cutting tool of the illustrated example, one end (the upper end in the illustrated example) where the cutting edge is not formed is set as a shank 25 that is still cylindrical. The two ends of the composite cutting tool can also be set as shanks. The shank 25 of the composite cutting tool is held on the spindle of a working machine such as a machining center, and the object is cut by abutting against the cutting edge of the object by rotating it around the rotating shaft 21. When one end is set as the shank, the composite cutting tool is held on the working machine in a cantilever state; when the end is set as the shank, the composite cutting tool is held on the working machine in a double-supported state.

[0037] The cutting edge 23 is arranged on the outer periphery of the main body 22 as described above. The cutting edge 23 has a cutting edge 23a, a front cutting edge 23b and a back cutting edge 23c. The front cutting edge 23b is the wall surface of the cutting edge 23 facing the rotation direction T. The front cutting edge 23b of the illustrated example is, in a cross section in a direction orthogonal to the rotation axis, arranged to define an arc recessed to the opposite side of the rotation direction T while extending toward the opposite side of the rotation direction T as it moves toward the outer peripheral side. The back cutting edge 23c is the outer peripheral surface of the cutting edge 23, and defines the cutting edge 23a by intersecting with the front cutting edge 23b. The back cutting edge 23c is substantially also the outer peripheral surface of the composite cutting tool 20. It is preferred to roughen the back cutting edge 23c. As a roughening treatment, any appropriate treatment can be adopted. As a representative example, shot peening can be cited. By roughening the back face, the adhesion of the adhesive and / or adhesive to the cutting edge is suppressed when the cutting object (represented by a resin sheet) includes an adhesive layer and / or an adhesive layer, and as a result, blocking can be suppressed. "Blocking" as described in this specification refers to the phenomenon that when the resin sheet includes an adhesive layer and / or an adhesive layer, the resin sheets at the workpiece are bonded to each other by the adhesive on the end surface, and the cutting chips of the adhesive attached to the end surface intensify the adhesion between the resin sheets.

[0038] As the number of cutting edges (the number of blades of the composite cutting tool), any appropriate number of blades can be adopted according to the purpose. The number of blades can be 1 blade, 2 blades, 3 blades, 4 blades as shown in the example, or 5 blades or more. Preferably, the number of blades is 2 blades or 4 blades. If it is such a structure, the rigidity of the blade can be ensured and the groove can be ensured so that the cutting chips can be discharged well. In the case where the number of blades is multiple (more than 2 blades), the multiple cutting blades can be formed at equal intervals in the circumferential direction as shown in the example, but they can also be formed at unequal intervals in the circumferential direction although not shown. Furthermore, in the case where the number of blades is multiple (more than 2 blades), it is representative that the rotation trajectories of the multiple cutting blades around the rotation axis 21 are consistent with each other.

[0039] Depending on the purpose, the helix angle θ of the cutting edge can be either 0° or a specific helix angle. That is, depending on the purpose, the cutting edge can be either a straight edge or a spiral edge. The helix angle θ of the cutting edge can be, for example, 0° to 65°, or 10° to 55°, or 20° to 50°, or 30° to 45°. In addition, the "helix angle of 0°" recorded in this specification means that the blade 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 of twist is caused by processing errors, etc.

[0040] Figure 2 FIG. 2 is a schematic top view of the main parts showing the detailed structure of the composite cutting tool 20. Figure 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 tip 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 tip angle θ2 of the cutting edge are in such a range, the machined surface obtained by the cutting edge is smoothed, so there is an advantage that the subsequent processing by the grinding part is further uniformed. In this specification, the "rake angle" is the angle formed by the straight line connecting the rotation axis 21 and the tip 23a and the straight line extending from the tip 23a along the front cutting surface 23b in the cross section in the direction perpendicular to the rotation axis; the "tip angle" is the angle formed by the straight line extending from the tip 23a along the front cutting surface 23b and the straight line extending from the tip 23a along the back cutting surface 23c in the cross section in the direction perpendicular to the rotation axis. In addition, when the front cutting face defines an arc in a cross section in a direction perpendicular to the rotation axis as shown in the example in the figure, the line extending along the front cutting face is a tangent line of the front cutting face extending from the cutting edge. In addition, the back cutting face is the outer peripheral surface of the cutting edge, and defines an arc in a cross section in a direction perpendicular to the rotation axis, so the line extending along the back cutting face is actually a tangent line of the back cutting face extending from the cutting edge. Furthermore, a negative (-: minus) front angle means that, in a cross section in a direction perpendicular to the rotation axis, the straight line extending from the cutting edge along the front cutting face is on the rotation direction T side (T) of the straight line connecting the rotation axis and the cutting edge. Figure 2 on the left side).

[0041] In an embodiment of the present invention, as described above, a grinding portion 24 is formed on a portion of the back blade 23c. The grinding portion 24 is provided as a protrusion having a file-like surface. The grinding portion 24 (substantially its surface) is representatively composed of diamond particles. If such a structure is used, a file-like surface having an appropriate surface roughness and surface hardness can be formed. The grinding portion 24 is representatively capable of functioning as a rotating grindstone. In the case where a plurality of cutting edges are provided, the grinding portion is representatively provided on each cutting edge. That is, representatively, the number of cutting edges is consistent with the number of grinding portions. Furthermore, the grinding portion is representatively provided at the corresponding position of each cutting edge. In addition, in the case where a plurality of grinding portions are formed, the plurality of grinding portions are the same as the case of the cutting edges, and representatively, the rotational trajectories around the rotation axis 21 are consistent with each other.

[0042] The protrusion height H of the grinding part 24 is preferably 0.1μm to 100μm, more preferably 1μm to 50μm, and even more preferably 5μm to 30μm. If the protrusion height H of the grinding part is in such a range, there is an advantage that the resin sheet will not melt or break in the processed surface formed by the grinding part, and a uniform processed surface can be obtained. Here, the protrusion height H of the grinding part is represented by H=R2-R1. R1 is the distance from the rotation axis 21 to the blade tip 23a, and R2 is the distance from the rotation axis 21 to the surface of the grinding part (protrusion) 24. R1 is the radius of the rotation track of the cutting edge 23, and R2 is also the radius of the rotation track of the grinding part 24. Therefore, the protrusion height H of the grinding part is the difference between the rotation radius of the grinding part and the rotation radius of the cutting edge. In the cross section of the grinding part in the direction perpendicular to the rotation axis, the wall surfaces on both sides of the grinding part can extend radially relative to the rotation axis, or can extend outward in a manner substantially perpendicular to the outer periphery (flank) of the cutting edge. Furthermore, in the cross section of the polishing section in the direction perpendicular to the rotation axis, the surface of the polishing section in the illustrated example is substantially flat and substantially coincides with the rotational trajectory of the polishing section.

[0043] The width W (mm) of the grinding portion 24 along the peripheral direction of the composite cutting tool 20 is preferably less than R1 (mm), more preferably less than 0.5×R1 (mm), and even more preferably 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 a small amount of clogging of the grinding portion by cutting chips, and the processing quality can be maintained at a certain level for a long time. In other words, the above advantages can be obtained by adjusting the width of the grinding portion according to the outer diameter of the composite cutting tool.

[0044] The position where the grinding portion 24 is provided on the back surface 23c of the cutting edge 23 can be appropriately set according to the purpose. In one embodiment, the distance L (mm) from the blade 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 blade tip 23a satisfy the following formula (1):

[0045] L≥0.1×R1…(1).

[0046] The distance L is preferably 0.1×R1 to 1.0×R1, and more preferably 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 the accumulation of cutting chips on the surface of the grinding part is small, and the processing quality can be maintained at a certain level for a long time. In other words, by setting the position of the grinding part in such a relationship according to the outer diameter of the composite cutting tool, the above advantages can be obtained.

[0047] The surface roughness of the grinding part 24 surface is preferably more than #60 as the number of the file, more preferably more than #100, and more preferably more than #200. The surface roughness is preferably below #2000 as the number of the file, more preferably below #1200, and more preferably below #800. If the surface roughness of the grinding part is in such a range, the resin sheet will not melt or break in the processing surface obtained by the grinding part, and the clogging of the grinding part by the cutting chips is small, and the processing quality can be maintained for a long time. In addition, the number of the file means that the smaller the number is, the coarser the abrasive gap is. The number can be adjusted by the amount, size, etc. of the diamond particles.

[0048] Figure 3 : This is a schematic cross-sectional view of the main parts used to illustrate the concavo-convex shape of the file-like surface of the grinding part 24. The depth D of the concavo-convex of the file-like surface of the grinding part 24 is, for example, 1μm to 120μm. The lower limit of the depth D is preferably 5μm or more, and more preferably 10μm or more. The upper limit of the depth D is preferably 50μm or less, and more preferably 35μm or less. The pitch p of the concavo-convex on the file-like surface of the grinding part 24 is, for example, 1μm to 250μm. The lower limit of the pitch p of the concavo-convex is preferably 5μm or more, and more preferably 10μm or more. The upper limit of the pitch p of the concavo-convex is preferably 100μm or less, and more preferably 60μm or less. If the concavo-convex shape of the surface of the grinding part is such a structure, there is an advantage that the resin sheet in the processed surface obtained by the grinding part will not melt or break, and there is less clogging of the cutting chips in the grinding part, and the processing quality can be maintained at a certain level for a long time.

[0049] The outer diameter of the composite cutting tool can be appropriately set according to the purpose. In more detail, 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, it can be processed without trouble using a working machine capable of general end milling. In addition, the outer diameter of the composite cutting tool is the value obtained by multiplying the R2 by 2 (i.e., the diameter of the rotating track of the grinding part).

[0050] In one embodiment, the cutting residual height Ph of each spacing 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 in 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 of being able to obtain a uniform machined surface. Here, the spacing P is represented by the following formula (2), and the cutting residual height Ph of each spacing is represented by the following formula (3):

[0051] P=F / (S×N)…(2)

[0052] Ph=arcsin(P / 2×R1)…(3)

[0053] In formula (2), F is the feed speed (mm / min) of the composite cutting tool, S is the rotation speed (rpm) of the composite cutting tool, and N is the number of cutting edges of the composite cutting tool.

[0054] The shape of the grinding portion 24 viewed from the rotation axis direction (the outer contour shape defining the surface of the grinding portion) can adopt any appropriate shape depending on the purpose and the like. Figure 4 (a)~ Figure 4 (e) are main part schematic plan views showing representative modified examples of the polishing section. Figure 4 The grinding portion of (a) has a substantially flat surface along the periphery from the wall surface facing the opposite side of the rotation direction to a specified portion in the rotation direction in a cross section in a direction perpendicular to the rotation axis, and the protrusion height gradually decreases from the specified portion to the wall surface facing the rotation direction. Figure 4 In the polishing portion of (b), in the cross section in the direction perpendicular to the rotation axis, the protrusion height gradually decreases from the wall surface facing the opposite side to the rotation direction to the wall surface facing the rotation direction. Figure 4 In the cross section of the grinding portion (c) in a direction perpendicular to the rotation axis, the protrusion height gradually decreases at a first inclination angle from the wall facing the opposite side of the rotation direction to a specified portion in the rotation direction, and the protrusion height gradually decreases at a second inclination angle larger than the first inclination angle from the specified portion to the wall facing the rotation direction. Figure 4In the cross section in the direction perpendicular to the rotation axis, the polishing portion of (d) has a wall surface facing the rotation direction extending toward the side opposite to the rotation direction as it goes toward the outside (protruding side). Figure 4 In the cross section of the grinding section (e) in the direction perpendicular to the rotation axis, the intersection of the line defining the surface of the grinding section and the line defining the wall surface in the rotation direction is chamfered. These modifications may also be appropriately combined. For example, Figure 4 (a)~ Figure 4 In the modified example (d), the intersection of the line defining the surface of the grinding portion and the line defining the wall surface in the rotation direction may also be chamfered; in addition, for example, Figure 4 (a)~ Figure 4 In the modification of (c), the wall surface facing the rotation direction may also extend toward the opposite side of the rotation direction as it faces the outside (protruding side). These modifications may be appropriately selected according to the protruding height H of the grinding portion, the position (distance L) where the grinding portion is set, the cutting residual height Ph, etc. For example, Figure 4 The modification of (b) may be useful when the protrusion height H of the grinding portion is large; Figure 4 The variation of (c) may be useful when the distance L is large; Figure 4 The modification of (d) may be useful when the cutting residual height Ph is small; Figure 4 The modification example (e) may be useful when the cutting residual height Ph is large. Figure 4 The modification example (a) may be useful when the protrusion height H, the distance L, and the residual cutting height Ph are all of medium magnitude.

[0055] B. Resin Sheet

[0056] As a resin sheet, any appropriate resin sheet that can be provided for end surface processing can be cited. The resin sheet can be either a film consisting of a single layer or a laminate. As a specific example of a resin sheet, an optical film, a heat insulation sheet, a resin window, a surface protection 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. Optical films require precise end surface processing compared to other resin sheets or films, so the effect of the embodiment of the present invention becomes significant. As a specific example of an optical film, a polarizer, a phase difference film, a polarizing plate (represented by a laminate of a polarizer and a protective film), a conductive film for a touch panel, a surface treatment film, and a laminate in which they are appropriately laminated according to the purpose (for example, a circular polarizer for preventing reflection, a polarizing plate with a conductive layer for a touch panel). 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 an optical film including a pressure-sensitive adhesive layer and / or an adhesive layer, the effect of the embodiment of the present invention is more significant.

[0057] C. Method for producing resin sheet

[0058] Hereinafter, a manufacturing method for a case where a polarizing plate with an adhesive layer is used as an example of a resin sheet is described. For a person 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 of the illustrated example. In addition, for a person skilled in the art, it is obvious that the embodiments of the present invention can also be applied to any appropriate resin sheet other than the polarizing plate with an adhesive layer. That is, the embodiments of the present invention can be used for the manufacture of any appropriate resin sheet having any appropriate shape.

[0059] C-1. Formation of workpiece

[0060] Figure 5 This is a schematic three-dimensional diagram for explaining the outline of the end surface processing of a resin sheet (here, a polarizing plate with an adhesive layer) in the manufacturing method of an embodiment of the present invention. In this figure, a workpiece W is shown. Figure 5As shown, a workpiece W is formed by overlapping multiple polarizing plates with adhesive layers. As a representative example, the polarizing plate with an adhesive layer is cut from a roll into any appropriate size and shape when the workpiece is formed. Specifically, the polarizing plate with an adhesive layer can be cut into a rectangular shape, a shape similar to a rectangular shape, or a shape corresponding to the purpose (for example, a circle). In the example shown in the figure, the polarizing plate with an adhesive layer is cut into a rectangular shape, and the workpiece W has peripheral surfaces (cutting surfaces) 1a, 1b facing each other and peripheral surfaces (cutting surfaces) 1c, 1d orthogonal to them. Cutting is performed by any appropriate unit. As a specific example of the cutting unit, punching and laser irradiation performed by a punching tool (for example, a Thomson tool) can be cited. In one embodiment, a release liner can also be temporarily attached to the surface of the adhesive layer of the polarizing plate with an adhesive layer, and / or a surface protective film can also be temporarily attached to the surface of the polarizing plate with an adhesive layer on the opposite side of the adhesive layer.

[0061] The total thickness of the workpiece is, for example, more than 3 mm, preferably more than 5 mm, more preferably more than 10 mm, more preferably more than 30 mm, and particularly preferably more than 60 mm. According to an embodiment of the present invention, by using a composite cutting tool as described in item A, even such a thick workpiece can be cut without trouble (represented by end surface processing). As a result, a resin sheet (here is 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 less than 150 mm, more preferably less than 100 mm. The upper limit of the total thickness of the workpiece is mainly due to the structural constraints of the working machine. In addition, according to an embodiment of the present invention, the effect becomes significant when the workpiece is thick, but of course it can be implemented without trouble even if the workpiece is of normal thickness (for example, less than 10 mm).

[0062] It is preferable to clamp the workpiece W from above and below with a clamping mechanism (not shown). The clamping mechanism (e.g., a fixture) may 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, an indentation caused by the clamping mechanism may remain. If the hardness is too low, positional deviation may occur due to deformation of the fixture, and the cutting accuracy may be insufficient.

[0063] C-2. End surface machining by composite cutting tool

[0064] 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.

[0065] 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.

[0066] The composite cutting tool can be held on the machine tool in a cantilever state or in a double-support state. By holding it in a cantilever state, the composite cutting tool can be easily moved in the plane and in the up-and-down directions. As a result, in the case where non-linear cutting (processing) is required, such cutting becomes easy. In addition, in the case of a cantilever, the composite cutting tool is easy to manufacture. On the other hand, by holding it in a double-support state, the shaking of the cutting surface (the unevenness of the cutting surface when viewed 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 therefore, the stability and reliability of the end face processing performed by the composite cutting tool can be improved.

[0067] The end surface processing of the resin sheet by the composite cutting tool can be performed on the entire peripheral surface of the resin sheet or on a portion of the peripheral surface. In the case where the resin sheet includes a polarizer (for example, in the case where the resin sheet is a polarizing plate with an adhesive layer as shown in the example), the end surface processing performed by the composite cutting tool is preferably performed only in the absorption axis direction of the polarizer. Figure 6 (a) and Figure 6 (b) is a schematic top view for explaining an example of a specific step of end surface processing of a resin sheet including a polarizer (here, a polarizing plate with an adhesive layer). In this embodiment, a representative polarizing plate with an adhesive layer is as follows: Figure 6 As shown in (a), the polarizer is cut into a rectangular shape so that the absorption axis A of the polarizer is in the short side direction.

[0068] Then, if Figure 6As shown in (a), the end surface of the short side is processed by an end mill. The end mill can adopt any appropriate structure according to the purpose and the type of resin sheet containing the polarizer. For example, the end mill can have the same structure as the composite cutting tool except that the grinding part is not provided, or it can have a completely different structure as a whole (for example, outer diameter, number of blades, helix angle, rake angle, and tool tip angle). The conditions for end surface processing performed by the end mill can be appropriately set according to the purpose, etc. 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 rotation speed (rotation speed) of the end mill can be, for example, 100 rpm to 50000 rpm, and can also be, for example, 1000 rpm to 35000 rpm, and can also be, for example, 2000 rpm to 20000 rpm. In addition, the feed speed of the end mill can be, for example, 100 mm / min to 5000 mm / min, and can also be, for example, 300 mm / min to 3000 mm / min. The number of times the end face of the short side of the workpiece (a resin sheet including a polarizer, in this case a polarizer with an adhesive layer) is cut by the end mill may be one cut, two cuts, three cuts or more. The example in the figure schematically shows two cuts for roughing and finishing. Roughing and finishing can be performed under the same conditions or under different conditions.

[0069] Then, if Figure 6 As shown in (b), the end surface of the long side is processed by a composite cutting tool. The structure of the composite cutting tool is as described in the above-mentioned item A, and the conditions for the end surface processing performed by the composite cutting tool are as described above. By performing such end surface processing, even a thick workpiece can be processed without trouble. Furthermore, cracks, dirtying and agglomeration of the cutting edge of the polarizing plate (represented by the polarizer) with an adhesive layer can be suppressed. In addition, in the case where a release liner and / or a surface protective film is temporarily attached to the polarizing plate with an adhesive layer, their warping can be suppressed. In the case of end surface processing of the entire periphery of the polarizing plate with an adhesive layer by an end mill, there are many cases where cutting residues occur because the cutting edge does not abut the workpiece. In the case of end surface processing of the entire periphery of the polarizing plate with an adhesive layer by a composite cutting tool, the processed end surface in the direction parallel to the absorption axis is afraid of the impact caused by thermal shock, and sometimes cracks are generated. However, when the resin sheet does not include a polarizing plate, even if the entire periphery of the resin sheet is end-face processed by a composite cutting tool, such a problem does not substantially occur.

[0070] [Example]

[0071] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. Evaluation items in the examples are as follows.

[0072] (1) Crack

[0073] The polarizing plates with adhesive layers obtained in Examples, Comparative Examples, and Reference Examples were bonded to a glass plate (thickness 1.1 mm) via the adhesive layer to prepare experimental samples.

[0074] (1-1) Cracks caused by thermal shock test

[0075] The test sample was subjected to a thermal shock test of 300 cycles of holding at -40°C for 30 minutes and then at 85°C for 30 minutes, and the state of crack generation after the test was observed by an optical microscope (magnification 5 times). Specifically, the number of cracks and their length (μm) were investigated and evaluated according to the following criteria.

[0076] A: The number is less than 10 and the maximum length is less than 500μm

[0077] B: The number is less than 10, but the maximum length exceeds 500μm

[0078] C: The number exceeds 10 and the maximum length exceeds 500 μm

[0079] (1-2) Cracks caused by heating test

[0080] The test samples were subjected to a heating test at 105° C. for 1000 hours and evaluated in the same manner as (1-1).

[0081] (2) Warping

[0082] The warping amount of the surface protective film and release liner of the polarizing plate with an adhesive layer obtained in Examples, Comparative Examples and Reference Examples was measured with a magnifying glass or a microscope. The maximum warping amount of one workpiece was defined as the warping amount, and the evaluation was performed according to the following criteria.

[0083] A: The amount of warping is less than 300μm

[0084] B: The amount of warping is more than 300μm and less than 500μm

[0085] C: The amount of warping exceeds 500μm

[0086] (3) Dirty blade

[0087] The contamination state of the cutting edge of the composite cutting tool after the end surface processing of the example and the cutting edge of the end mill after the end surface processing of the comparative example and the reference example due to the adhesive was observed and evaluated according to the following criteria.

[0088] A: No contamination has been confirmed.

[0089] B: Contamination was confirmed, but no problems occurred during processing

[0090] C: Significant contamination was confirmed, and problems occurred during processing

[0091] (4) Agglomeration

[0092] The states of the workpieces after the end surface processing in the examples, comparative examples, and reference examples were observed and evaluated based on the following criteria.

[0093] A: It is easy to separate the polarizing plates with adhesive layer from the workpiece.

[0094] B: Although the polarizing plates with adhesive layers can be separated from the workpiece, the separation operation is difficult.

[0095] C: The workpiece is completely in a block, and the polarizing plates with adhesive layers cannot be separated one by one.

[0096] <Example 1>

[0097] By the usual method, a polarizing plate with an adhesive layer having a structure of surface protection film (60μm) / cycloolefin protective film (47μm) / polarizer (5μm) / cycloolefin protective film (24μm) / adhesive layer (20μm) / peel-off liner in order from the visual side was prepared. In addition, as a surface protective film, a surface protective film having a structure of PET substrate (50μm) / adhesive layer (10μm) was used. The polarizing plate with an adhesive layer was punched into a size of 5.7 (140mm vertically and about 65mm horizontally). Here, the punching is performed in a manner that the absorption axis direction of the polarizer is horizontal (short side direction). Multiple pieces of the punched polarizing plate with an adhesive layer are overlapped to form a workpiece. The total thickness of the workpiece is 45mm. While the obtained workpiece is clamped by a clamp (fixture), the end face of the short side (absorption axis direction of the polarizer) is processed by an end mill. Specifically, an end mill with an outer diameter of 9 mm, double edges and a helix angle of 45° was used to provide each short side for two end face processing including rough machining and fine machining. The cutting amount of rough machining is 0.2 mm, and the cutting amount of fine machining is 0.1 mm. In either rough machining or fine machining, the feed speed of the end mill is 1000 mm / min and the rotation speed is 35000 rpm. Next, the end face processing of the long side (in the direction orthogonal to the absorption axis direction of the polarizer) was performed by a composite cutting tool according to an embodiment of the present invention. A composite cutting tool having a grinding portion with a protrusion height of 20 μm provided on the back face of the cutting edge of the end mill was used. The protruding surface of the grinding portion is a file (or a rotating grindstone) containing diamond particles. The distance L from the tip of the cutting edge to the wall of the grinding portion facing the rotation direction is 0.9 mm, and has a relationship of L=0.167×R1 with the distance R1 from the rotation axis to the tip of the cutting edge. The end face processing of the long side was performed twice under the same conditions. Specifically, the feed speed of the composite cutting tool is 1000 mm / min, the rotation speed is 8000 rpm, and the cutting amount per time is 0.1 mm. In this way, a polarizing plate with an adhesive layer is obtained. In end surface processing, there is no need to precisely adjust the holding state of the end mill and the composite cutting tool to the working machine, and uniform cutting is achieved throughout the thickness direction of the workpiece. The above-mentioned (1) to (4) evaluations were performed on the obtained polarizing plate with an adhesive layer. The results are shown in Table 1.

[0098] <Example 2>

[0099] 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 surface processing, it was not necessary to precisely adjust the holding state of the end mill and the composite cutting tool to the working machine, and uniform cutting was achieved throughout the thickness direction of the workpiece. The obtained polarizing plate with an adhesive layer was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0100] <Comparative Example 1>

[0101] For all the edges (the entire periphery) of the workpiece formed in the same manner as in Example 1, end surface processing was performed only using an end mill. Specifically, the entire periphery of the workpiece was subjected to two end surface processing steps including rough processing and fine processing in one stroke. The conditions for rough processing and fine processing were the same as in Example 1. Next, only the long sides were end surface processed using a rotary grindstone (#400). The rotation speed of the rotary grindstone was 1000 rpm, and the feed speed was 500 mm / min. In this way, a polarizing plate with an adhesive layer was obtained. During the end surface processing of the end mill, poor cutting occurred in a portion of the workpiece (the upper end or the lower end in the thickness direction). The poor cutting was significant in the long sides. The obtained polarizing plate with an adhesive layer was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0102] <Reference Example 1>

[0103] 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 failure was observed in the end surface processing. The obtained polarizing plate with an adhesive layer was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0104] [Table 1]

[0105]

[0106] <Evaluation>

[0107] As can be seen from Table 1, the composite cutting tool according to the embodiment of the present invention can cut a thick workpiece without any trouble.

[0108] Industrial Applicability

[0109] The composite cutting tool according to the embodiment of the present invention can be suitably used for the production of a resin sheet (particularly, end surface processing during the production). The resin sheet may be, for example, an optical film.

[0110] Description of symbols

[0111] W workpiece

[0112] 20Compound cutting tools

[0113] 21 Rotation axis

[0114] 22 Main Body

[0115] 23 cutting edges

[0116] 23a blade tip

[0117] 23b rake face

[0118] 23c back face

[0119] 24 Grinding Department

Claims

1. A composite cutting tool for cutting an optical film comprising an adhesive layer and / or a bonding agent layer, 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; as well as a grinding portion provided as a protrusion having a file-like surface on a portion of the flank surface of the cutting edge; The composite cutting tool is integrally formed of a hard metal material; The helix angle of the cutting edge is 10° to 55°; The grinding part has a wall surface facing the rotation direction and a wall surface facing the opposite side to the rotation direction in a cross section in a direction perpendicular to the rotation axis; The protrusion height H of the grinding portion is 0.1 μm to 150 μm; The distance L from the blade tip to the wall surface of the grinding portion in the rotation direction and the following distance R1 satisfy the following formula (1): L ≥ 0.1 × R1…(1) Here, the protrusion height H is represented by H=R2-R1, R1 is the radius of the rotation track of the cutting edge, and R2 is the radius of the rotation track of the grinding part.

2. The composite cutting tool according to claim 1, wherein: The wall surface facing the rotation direction and the wall surface facing the side opposite to the rotation direction extend radially outward relative to the rotation axis, or extend outward substantially orthogonally to the flank surface of the cutting edge.

3. The composite cutting tool according to claim 1, wherein: The polishing portion includes diamond particles.

4. The composite cutting tool according to claim 1, wherein: The rake angle θ1 is -30° to 45°, and the tool tip angle θ2 is 20° to 100°; Here, the front angle is the angle formed by a straight line connecting the rotation axis and the cutting edge and a straight line extending from the cutting edge along the front cutting surface in a cross section in a direction perpendicular to the rotation axis; the cutting edge angle is the angle formed by a straight line extending from the cutting edge along the front cutting surface and a straight line extending from the cutting edge along the back cutting surface in a cross section in a direction perpendicular to the rotation axis.

5. A method for manufacturing a resin sheet, comprising: Overlapping multiple resin sheets to form a workpiece; as well as cutting the outer peripheral surface of the workpiece by the composite cutting tool according to any one of claims 1 to 4; The resin sheet includes an optical film, and the optical film includes a pressure-sensitive adhesive layer and / or an adhesive layer.

6. The manufacturing method according to claim 5, wherein: The thickness of the workpiece is 30 mm or more.

Images