JP2023155332A - Composite cutting tool and method for manufacturing resin sheet using the same - Google Patents

Abstract

To provide a composite cutting tool capable of cutting even a thick workpiece without a trouble, and a method capable of highly efficiently and easily manufacturing a resin sheet using the same.SOLUTION: This composite cutting tool comprises: a body that rotates about a rotation axis; a cutting blade that has a blade tip, a cutting face, and a relief surface and that is provided in the outer peripheral part of the body; and a polishing part provided as a projected part having a file-like surface in a part of the relieve surface of the cutting blade. A method for manufacturing a resin sheet comprises stacking a plurality of resin sheets to form a workpiece, and cutting the outer peripheral surface of the workpiece by the composite cutting tool.SELECTED DRAWING: Figure 1A

Description

The present invention relates to a composite cutting tool and a method for manufacturing a resin sheet using the same.

Various resin sheets are widely used depending on the purpose. After the resin sheet is cut into a predetermined shape, the outer peripheral end surface may be subjected to finishing processing. In such finishing machining, cutting with an end mill may be performed. Cutting with an end mill is usually performed on a workpiece made of a plurality of stacked resin sheets. Here, in consideration of manufacturing efficiency, it is preferable to cut a thick workpiece. However, when cutting a thick workpiece, if the endmill is tilted, there may be a portion of the workpiece where the endmill does not come into contact. Therefore, there are problems in that the state in which the end mill is held in the machine tool must be precisely adjusted, and the thickness of the workpiece must be kept below a certain value, resulting in insufficient manufacturing efficiency.

Japanese Patent Application Publication No. 2009-196015

The present invention has been made to solve the above-mentioned conventional problems, and its main purpose is to provide a composite cutting tool that can cut even thick workpieces without any problems, and a method using such a composite cutting tool. An object of the present invention is to provide a method for manufacturing a resin sheet easily and efficiently.

A composite cutting tool according to an embodiment of the present invention includes: a main body that rotates around a rotation axis; a cutting blade provided on the outer periphery of the main body and having a cutting edge, a rake surface, and a relief surface; a relief surface of the cutting blade; and a polishing portion provided as a protrusion having a file-like surface on a part of the surface.
In one embodiment, the protrusion height H of the polishing portion is 0.1 μm to 150 μm. Here, the protrusion height H is expressed as H=R2-R1, where R1 is the distance from the rotation axis to the cutting edge, and R2 is the distance from the rotation axis to the surface of the protrusion.
In one embodiment, the distance L from the cutting edge to the wall surface facing the rotational direction of the polishing section and R1 satisfy the following formula (1):
L≧0.1×R1 (1).
In one embodiment, the composite cutting tool has an uncut height Ph of 0.03 μm to 280 μm per pitch. Here, the pitch P is expressed by the following formula (2), and the uncut height Ph for each pitch is expressed by the following formula (3):
P=F/(S×N)...(2)
Ph=arcsin(P/2×R1)...(3)
In equation (2), F is the feed rate (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 blades of the composite cutting tool.
In one embodiment, the polishing portion includes diamond particles.
In one embodiment, the composite cutting tool has a rake angle θ1 of −30° to 45° and a cutting edge angle θ2 of 20° to 100°. Here, the rake angle is the angle between a straight line connecting the rotating shaft and the cutting edge and a straight line extending from the cutting edge along the rake face in a cross section perpendicular to the rotating shaft; An angle is an angle between a straight line extending from the cutting edge along the rake surface and a straight line extending from the cutting edge along the release surface in a cross section in a direction perpendicular to the rotation axis.
According to another aspect of the present invention, a method for manufacturing a resin sheet is provided. The manufacturing method includes stacking a plurality of resin sheets to form a workpiece, and cutting the outer peripheral surface of the workpiece with the above-mentioned composite cutting tool.
In one embodiment, the thickness of the workpiece is 30 mm or more.
In one embodiment, the resin sheet includes an adhesive layer and/or a pressure-sensitive adhesive layer.
In one embodiment, the resin sheet includes an optical film. In one embodiment, the optical film includes a polarizer.

According to the embodiments of the present invention, it is possible to realize a composite cutting tool that can cut even a thick workpiece without any problems. By using such a composite cutting tool, it is possible to realize a method of manufacturing a resin sheet easily and with high efficiency.

FIG. 1 is a schematic plan view of a composite cutting tool according to one embodiment of the present invention, viewed from the rotation axis direction. 1B is a schematic perspective view of the composite cutting tool of FIG. 1A; FIG. 1 is a schematic plan view of main parts showing a detailed structure of a composite cutting tool according to one embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a main part for explaining the depth and pitch of irregularities on the surface of a polishing part in a composite cutting tool according to an embodiment of the present invention. FIGS. 4(a) to 4(e) are schematic plan views of main parts showing modified examples of the polishing part in the composite cutting tool according to the embodiment of the present invention. It is a schematic perspective view for explaining the outline of end face processing of the resin sheet in the manufacturing method according to the embodiment of the present invention. FIGS. 6A and 6B are schematic plan views for explaining an example of end face processing when the resin sheet includes a polarizer in the manufacturing method according to the embodiment of the present invention.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. Note that the drawings are shown schematically for ease of viewing, and the ratios of length, width, thickness, etc., angles, etc. in the drawings are different from the actual ones. Further, in order to facilitate understanding of detailed shapes and the meanings of symbols in the figures, the shapes may not correspond exactly between the drawings.

A. Compound Cutting Tool FIG. 1A is a schematic plan view of a compound cutting tool according to one embodiment of the present invention, viewed from the direction of the rotation axis; FIG. 1B is a schematic perspective view of the compound cutting tool of FIG. 1A. The illustrated composite cutting tool 20 includes a main body 22 that rotates around a rotating shaft 21; a cutting blade 23 that is provided on the outer circumference of the main body 22 and has a cutting edge 23a, a rake surface 23b, and a relief surface 23c; A polishing part 24 is provided as a protrusion having a file-like surface on a part of the relief surface of the blade 23.

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 rotating shaft 21 . In the illustrated composite cutting tool, one end (in the illustrated example, the upper end) where no cutting edge is formed is a shank portion 25 that remains cylindrical. Both ends of the composite cutting tool may serve as shank portions. The shank portion 25 of the compound cutting tool is held by the main shaft of a machine tool such as a machining center and rotated around the rotating shaft 21, so that the cutting blade in contact with the object cuts the object. If one end is a shank, the compound cutting tool is held cantilevered on the machine tool; if one end is a shank, the compound cutting tool is held double-sided on the machine tool. .

The cutting blade 23 is provided on the outer circumference of the main body 22 as described above. The cutting blade 23 has a cutting edge 23a, a rake surface 23b, and a relief surface 23c. The rake face 23b is a wall face facing the rotation direction T of the cutting blade 23. In the illustrated example, the rake face 23b defines an arc concave on the side opposite to the rotation direction T in a cross section in a direction perpendicular to the rotation axis, and is shaped so as to move toward the side opposite to the rotation direction T toward the outer circumference. It is extending. The relief surface 23c is the outer peripheral surface of the cutting blade 23, and intersects with the rake surface 23b to define the cutting edge 23a. The relief surface 23c is also substantially the outer peripheral surface of the composite cutting tool 20. The relief surface 23c is preferably roughened. Any suitable treatment may be employed as the surface roughening treatment. A typical example is blasting. By roughening the relief surface, when the object to be cut (typically, a resin sheet) includes an adhesive layer and/or an adhesive layer, it is possible to prevent the adhesive and/or adhesive from being applied to the cutting blade. Adhesion may be suppressed and, as a result, blocking may be suppressed. In this specification, "blocking" refers to a phenomenon in which resin sheets in a workpiece adhere to each other with adhesive on the end surfaces when the resin sheets include a pressure-sensitive adhesive layer and/or an adhesive layer. Scraps of the agent and the like contribute to adhesion between the resin sheets.

As the number of cutting blades (the number of blades of the composite cutting tool), any appropriate number of blades may be adopted depending on the purpose. The number of blades may be one, two, three, four as in the illustrated example, or five or more. Preferably, the number of blades is two or four. With such a configuration, the rigidity of the blade is ensured, pockets are ensured, and the shavings can be discharged satisfactorily. When the number of cutting blades is plural (two or more), the plurality of cutting blades may be formed at equal intervals in the circumferential direction as in the illustrated example, or may be formed at unequal intervals in the circumferential direction (not shown). It's okay. Further, when the number of cutting blades is plural (two or more), typically, the rotation trajectories of the plurality of cutting blades around the rotation axis 21 are made to coincide with each other.

The cutting blade may have a helix angle Θ of 0° or a specific helix angle depending on the purpose. That is, the cutting blade may be a straight blade or a twisted blade depending on the purpose. The helix angle Θ of the cutting blade may be, for example, 0° to 65°, or may be, for example, 10° to 55°, or may be, for example, 20° to 50°, or may be, for example, 30°. It may be ~45°. Note that in this specification, “the helix angle is 0°” means that the cutting edge 23a extends in a direction substantially parallel to the rotating shaft 21. Note that "0°" means substantially 0°, and also includes cases where the angle is slightly twisted due to processing errors or the like.

FIG. 2 is a schematic plan view of the main parts showing the detailed structure of the composite cutting tool 20. As shown in FIG. As shown in FIG. 2, the rake angle θ1 of the cutting blade is preferably -30° to 45°, more preferably -10° to 30°, and still more preferably 0° to 20°; The angle θ2 is preferably 20° to 100°, more preferably 30° to 90°, and still more preferably 45° to 80°. If the rake angle θ1 and the cutting edge angle θ2 of the cutting blade are within such ranges, the surface processed by the cutting blade is smoothed, so there is an advantage that subsequent processing by the polishing section is made more uniform. In this specification, "rake angle" refers to the angle between a straight line connecting the rotating shaft 21 and the cutting edge 23a and a straight line extending from the cutting edge 23a along the rake face 23b in a cross section perpendicular to the rotating axis. "Blade angle" is the angle formed by a straight line extending from the cutting edge 23a along the rake surface 23b and a straight line extending from the cutting edge 23a along the relief surface 23c in the cross section in the direction perpendicular to the rotation axis. be. Note that when the rake face defines an arc in the cross section in the direction perpendicular to the rotation axis as in the illustrated example, the line extending along the rake face is a tangent to the rake face extending from the cutting edge. In addition, the relief surface is the outer circumferential surface of the cutting blade and defines an arc in the cross section perpendicular to the rotation axis, so the line extending along the relief surface is essentially the tangent to the relief surface extending from the cutting edge. be. Furthermore, a negative (-: minus) rake angle means that in a cross section perpendicular to the rotation axis, a straight line extending from the cutting edge along the rake face is closer to the rotational direction T than the straight line connecting the rotation axis and the cutting edge (see Fig. (left side of 2).

In the embodiment of the present invention, as described above, the polishing portion 24 is formed in a part of the relief surface 23c. The polishing section 24 is provided as a protrusion having a file-like surface. Polishing portion 24 (substantially the surface thereof) typically includes diamond particles. With such a configuration, a file-like surface having appropriate surface roughness and surface hardness can be formed. The polishing section 24 can typically function as a rotating grindstone. When a plurality of cutting blades are provided, the polishing portion is typically provided on each cutting blade. That is, typically, the number of cutting blades and the number of polishing parts match. Further, the polishing portions are typically provided at corresponding positions on each cutting blade. Note that when a plurality of abrasive parts are formed, the rotation trajectories of the plurality of abrasive parts about the rotation axis 21 are typically made to coincide with each other, similarly to the case of a cutting blade.

The protrusion height H of the polishing portion 24 is preferably 0.1 μm to 100 μm, more preferably 1 μm to 50 μm, and still more preferably 5 μm to 30 μm. If the protrusion height H of the polishing part is within such a range, there is an advantage that a uniform processed surface can be obtained without melting or damaging the resin sheet on the surface processed by the polishing part. Here, the protrusion height H of the polishing part is expressed as H=R2-R1. R1 is the distance from the rotating shaft 21 to the cutting edge 23a, and R2 is the distance from the rotating shaft 21 to the surface of the polishing portion (projection) 24. R1 is also the radius of the rotational orbit of the cutting blade 23, and R2 is also the radius of the rotational orbit of the polishing section 24. Therefore, the protrusion height H of the abrasive part is the difference between the radius of rotation of the abrasive part and the radius of rotation of the cutting blade. In the illustrated polishing section, in a cross section perpendicular to the rotation axis, the wall surfaces on both sides of the polishing section may extend radially with respect to the rotation axis, and are substantially connected to the outer periphery (relief surface) of the cutting blade. They may extend outward to cross at right angles. Further, in the illustrated polishing section, the surface of the polishing section is substantially flat in a cross section in a direction perpendicular to the rotation axis, and substantially coincides with the rotation orbit of the polishing section.

The width W (mm) of the polishing portion 24 along the outer circumferential direction of the composite cutting tool 20 is preferably R1 (mm) or less, more preferably 0.5×R1 (mm) or less, and even more preferably 0. .3×R1 (mm) or less. The lower limit of the width W of the polishing portion may be, for example, 0.01×R1 (mm). If the width W of the polishing part is within such a range, there is an advantage that the polishing part is less likely to be clogged with cutting debris, and machining quality can be maintained constant over a long period of time. In other words, the above advantages can be obtained by adjusting the width of the polishing part according to the outer diameter of the composite cutting tool.

The position where the polishing portion 24 is provided on the release surface 23c of the cutting blade 23 can be appropriately set depending on the purpose. In one embodiment, the distance L (mm) from the cutting edge 23a to the wall surface facing the rotational direction of the polishing section 24 and the distance R1 (mm) from the rotating shaft 21 to the cutting edge 23a are expressed by the following formula (1). Satisfied:
L≧0.1×R1 (1).
The distance L is preferably 0.1×R1 to 1.0×R1, more preferably 0.15×R1 to 0.8×R1. If the distance L and the distance R1 have such a relationship, there is an advantage that there is little accumulation of debris on the surface of the polishing part and that the processing quality can be kept constant over a long period of time. In other words, the above advantages can be obtained by defining the position where the polishing portion is provided in accordance with the outer diameter of the composite cutting tool.

The surface roughness of the polishing portion 24 is preferably #60 or more, more preferably #100 or more, and still more preferably #200 or more in terms of the number of the file blade. The surface roughness may be preferably #2000 or less, more preferably #1200 or less, and still more preferably #800 or less in terms of the number of the file blade. If the surface roughness of the polishing section is within this range, the resin sheet will not melt or break on the surface processed by the polishing section, and the polishing section will be less likely to be clogged with cutting scum, ensuring high processing quality over a long period of time. It has the advantage that it can be kept constant. Note that the smaller the number of the file blade, the coarser it is. The count can be adjusted by adjusting the amount, size, etc. of diamond particles.

FIG. 3 is a schematic sectional view of a main part for explaining the uneven shape of the file-like surface of the polishing part 24. As shown in FIG. The depth D of the unevenness on the file-like surface of the polishing portion 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 on the file-like surface of the polishing portion 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 surface of the polishing section has such a structure, the resin sheet will not melt or break on the surface processed by the polishing section, and the polishing section will be less likely to be clogged with cutting debris, and the processing quality will be maintained for a long time. It has the advantage that it can be kept constant.

The outer diameter of the composite cutting tool can be appropriately set depending on 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, even more preferably 1 mm to 20 mm. If the outer diameter of the composite cutting tool is within this range, it can be machined without any problems using a machine tool capable of general end milling. Note that the outer diameter of the composite cutting tool is twice the above R2 (that is, the diameter of the rotational orbit of the polishing part).

In one embodiment, the uncut height Ph for each pitch of the composite cutting tool is preferably 0.03 μm to 280 μm, more preferably 0.1 μm to 100 μm, and still more preferably 0.2 μm to 280 μm. It is 10 μm. If the uncut height Ph is within such a range, there is an advantage that a uniform processed surface can be obtained without melting or damaging the resin sheet on the processed surface by the polishing section. Here, the pitch P is expressed by the following formula (2), and the uncut height Ph for each pitch is expressed by the following formula (3):
P=F/(S×N)...(2)
Ph=arcsin(P/2×R1)...(3)
In equation (2), F is the feed rate (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 blades of the composite cutting tool.

The shape of the polishing section 24 (the contour shape defining the surface of the polishing section) viewed from the direction of the rotation axis may be any suitable shape depending on the purpose and the like. FIGS. 4(a) to 4(e) are schematic plan views of main parts showing typical modifications of the polishing section. The polishing portion in FIG. 4(a) has a substantially flat surface along the outer periphery from the wall surface facing the opposite side to the rotation direction to a predetermined portion in the rotation direction in a cross section in a direction perpendicular to the rotation axis, The protrusion height gradually decreases from the predetermined portion to the wall surface facing the rotation direction. In the polishing section of FIG. 4(b), 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 in a cross section taken in a direction perpendicular to the rotation axis. In the polishing part of FIG. 4(c), in the cross section in the direction perpendicular to the rotation axis, the protrusion height gradually decreases at the first inclination angle from the wall surface facing the opposite side to the rotation direction to a predetermined portion in the rotation direction, The protrusion height gradually decreases from the predetermined portion to the wall surface facing the rotation direction at a second inclination angle that is larger than the first inclination angle. In the polishing section of FIG. 4(d), in a cross section taken in a direction perpendicular to the rotation axis, the wall surface facing the rotation direction extends toward the outside (projecting side) toward the opposite side to the rotation direction. The polishing part in FIG. 4(e) has a shape in which the intersection of the line defining the polishing part surface and the line defining the wall surface facing the rotation direction is chamfered in the cross section in the direction perpendicular to the rotation axis. . These modifications may be combined as appropriate. For example, in the modified examples of FIGS. 4(a) to 4(d), the intersection of the line defining the surface of the polishing part and the line defining the wall surface facing the rotation direction may be chamfered. Also, for example, in the modified examples shown in FIGS. 4(a) to 4(c), the wall surface facing the rotation direction may extend toward the outside (projecting side) in the opposite direction to the rotation direction. These modifications can be appropriately selected depending on the protruding height H of the polishing part, the position (distance L) where the polishing part is provided, the uncut height Ph, and the like. For example, the modification of FIG. 4(b) may be useful when the protrusion height H of the polishing part is large; the modification of FIG. 4(c) may be useful when the distance L is large; The modification of FIG. 4(d) may be useful when the uncut height Ph is small; the modification of FIG. 4(e) may be useful when the uncut height Ph is large. Moreover, the modification of FIG. 4(a) may be useful when the protrusion height H, the distance L, and the uncut height Ph are all intermediate in size.

B. Resin Sheet Examples of the resin sheet include any suitable resin sheet that can be subjected to end surface processing. The resin sheet may be a film composed of a single layer, or may be a laminate. Specific examples of resin sheets include optical films, heat insulating sheets, resin windows, surface protection films, fiber reinforced plastic (FRP) sheets, packaging films, and food films. In one embodiment, the resin sheet includes an optical film. Since optical films require more precise edge processing than other resin sheets or films, the effects of the embodiments of the present invention are significant. Specific examples of optical films include polarizers, retardation films, polarizing plates (typically laminates of polarizers and protective films), conductive films for touch panels, surface treatment films, and films for these purposes. A laminate suitably laminated according to the purpose (for example, a circularly polarizing plate for antireflection, a polarizing plate with a conductive layer for a touch panel) can be mentioned. In one embodiment, the resin sheet includes an adhesive layer and/or a pressure-sensitive adhesive layer. Therefore, the resin sheet can be, for example, an optical film including an adhesive layer and/or a pressure-sensitive adhesive layer. In an optical film containing an adhesive layer and/or a pressure-sensitive adhesive layer, the effects of the embodiments of the present invention are even more remarkable.

C. Manufacturing method of resin sheet Hereinafter, a manufacturing method when a polarizing plate with an adhesive layer is adopted as an example of a resin sheet will be described. It is obvious to those skilled in the art that the planar shape of the adhesive layer-attached polarizing plate is not limited to the planar shape of the illustrated example. Furthermore, it is obvious to those skilled in the art that the embodiments of the present invention can be applied to any appropriate resin sheet other than a polarizing plate with an adhesive layer. That is, embodiments of the present invention can be applied to manufacturing any suitable resin sheet having any suitable shape.

C-1. Formation of Workpiece FIG. 5 is a schematic perspective view for explaining the outline of end face processing of a resin sheet (here, a polarizing plate with an adhesive layer) in a manufacturing method according to an embodiment of the present invention. A workpiece W is shown in this figure. As shown in FIG. 5, a workpiece W is formed by stacking a plurality of polarizing plates with adhesive layers. When forming a workpiece, a polarizing plate with an adhesive layer is typically cut from a raw roll into any suitable size and shape. Specifically, the polarizing plate with an adhesive layer may be cut into a rectangular shape, a shape similar to a rectangular shape, or an appropriate shape (for example, circular) depending on the purpose. may have been done. In the illustrated example, the polarizing plate with an adhesive layer is cut into a rectangular shape, and the workpiece W has outer circumferential surfaces (cut surfaces) 1a and 1b facing each other and outer circumferential surfaces (cut surfaces) 1c and 1d perpendicular thereto. have. Cutting is performed by any suitable means. Specific examples of the cutting means include punching with a punching blade (eg, Thomson blade) and laser irradiation. In one embodiment, a release liner may be temporarily attached to the surface of the adhesive layer of the polarizing plate with an adhesive layer, and/or a release liner may be temporarily attached to the surface of the polarizing plate with an adhesive layer opposite to the adhesive layer. A surface protection film may be temporarily attached to the surface.

The total thickness of the workpiece is, for example, 3 mm or more, preferably 5 mm or more, more preferably 10 mm or more, still more preferably 30 mm or more, and particularly preferably 60 mm or more. According to an embodiment of the present invention, by using a composite cutting tool as described in Section A above, even such a thick workpiece can be cut (typically, end face processing) without any problems. can. As a result, a resin sheet (here, a polarizing plate with an adhesive layer) can be manufactured easily and with high efficiency. 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 may be mainly due to constraints on the configuration of the machine tool. Although the embodiment of the present invention is more effective when the workpiece is thick, it goes without saying that the present invention can be carried out without any problems even if the workpiece has a normal thickness (for example, 10 mm or less).

The workpiece W is preferably clamped from above and below by clamping means (not shown). The clamping means (e.g. jig) may be constructed of soft or hard material. When it is made of a soft material, its hardness (JIS A) is preferably 60° to 80°. If the hardness is too high, pressure marks caused by the clamping means may remain. If the hardness is too low, positional deviation may occur due to deformation of the jig, resulting in insufficient cutting accuracy.

C-2. End face machining using a composite cutting tool Next, a predetermined position on the outer peripheral surface of the workpiece W is cut (end face machining) using the composite cutting tool 20. The compound cutting tool 20 is typically held in a machine tool (not shown), is rotated at high speed around the rotation axis of the compound cutting tool, and is fed out in a direction intersecting the rotation axis, so that the cutting blade is inserted into the workpiece W. It is used by making a cut in the outer circumferential surface of the That is, cutting is typically performed by bringing a cutting blade of a compound cutting tool into contact with the outer circumferential surface of the workpiece W to cut into it. Furthermore, according to the embodiment of the present invention, following the cutting by the cutting blade, polishing (cutting) is performed by the polishing part whose rotation orbit has a larger radius than the cutting blade. By additionally performing cutting with such a grinding part, there is no problem even with thick workpieces (more specifically, there is no uncut material due to the cutting blade not contacting the workpiece, and the thickness of the workpiece is reduced. End face processing can be performed uniformly over the entire direction. Furthermore, cracks in the adhesive layer-attached polarizing plate (typically, the polarizer), staining of the cutting blade, and blocking can be suppressed. In particular, the progression of cracks over time can be effectively suppressed. In addition, when a release liner and/or a surface protection film are temporarily attached to the adhesive layer-attached polarizing plate, lifting of these can be suppressed. Here, the term "blade fouling of the cutting blade" refers to a phenomenon in which the adhesive of the adhesive layer adheres to the cutting blade and the cutting performance (processing performance) deteriorates beyond the allowable range. Blocking is as described above.

Conditions for end face processing using the composite cutting tool can be appropriately set depending on the type of resin sheet, desired shape, etc. For example, the rotational speed (rotational speed) of the composite cutting tool is preferably 100 rpm to 50,000 rpm, more preferably 1,000 rpm to 30,000 rpm, and still more preferably 2,000 rpm to 20,000 rpm. Further, for example, the feed rate of the composite cutting tool is preferably 100 mm/min to 5,000 mm/min, more preferably 200 mm/min to 4,000 mm/min, and still more preferably 300 mm/min to 3,000 mm. /minute. If the rotational speed and feed rate of the compound cutting tool are within such ranges, end face machining can be performed without problems even on thick workpieces. The number of times the end face of the workpiece (resin sheet) is cut by the composite cutting tool may be one cut, two cuts, three cuts, or more.

The composite cutting tool may be held on a machine tool in a cantilevered state, or may be held in a double-sided state. By holding it in a cantilevered state, the compound cutting tool can be easily moved in the plane and in the vertical direction. As a result, when non-linear cutting (processing) is required, such cutting becomes easy. Moreover, it is easier to manufacture a composite cutting tool with a cantilever. On the other hand, by holding the cutting surface in a state where it is held at both ends, it is possible to suppress rattling of the cut surface (unevenness when the cutting surface is viewed from the lateral direction). Furthermore, by holding the tool in a dual-supported state, stress applied to the cutting blade of the compound 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 end face machining using the composite cutting tool can be improved.

The end face processing of the resin sheet using the composite cutting tool may be performed on the entire outer peripheral surface of the resin sheet, or may be performed on a part of the outer peripheral surface. When the resin sheet includes a polarizer (for example, when the resin sheet is a polarizing plate with an adhesive layer as shown in the illustration), the end face processing using a composite cutting tool is preferably carried out only in the absorption axis direction of the polarizer. It will be held on. FIGS. 6(a) and 6(b) are schematic plan views for explaining an example of a specific procedure for end face processing of a resin sheet containing a polarizer (here, a polarizing plate with an adhesive layer). . In this embodiment, the adhesive layer-attached polarizing plate is typically cut into a rectangular shape with the absorption axis A of the polarizer oriented in the short side direction, as shown in FIG. 6(a). .

Next, as shown in FIG. 6(a), the end face of the short side is processed using an end mill. The end mill may have any suitable configuration depending on the purpose and the type of resin sheet containing the polarizer. For example, an end mill may have a configuration similar to that of a compound cutting tool except that it does not include a grinding part, and may have a completely different configuration as a whole (e.g., outer diameter, number of teeth, helix angle, rake angle, cutting edge angle). ). Conditions for end face processing using an end mill can be appropriately set depending on the purpose and the like. The outer diameter of the end mill may be, for example, 0.5 mm to 30 mm, or may be, for example, 1 mm to 20 mm. The rotation speed (rotation speed) of the end mill may be, for example, 100 rpm to 50,000 rpm, or may be, for example, 1,000 rpm to 35,000 rpm, or may be, for example, 2,000 rpm to 20,000 rpm. good. Further, the feed speed of the end mill may be, for example, 100 mm/min to 5,000 mm/min, or may be, for example, 300 mm/min to 3,000 mm/min. The number of times the short side end face of the workpiece (resin sheet containing a polarizer, here a polarizing plate with an adhesive layer) is cut by the end mill may be one cut, two cuts, three cuts, or more. The illustrated example schematically shows two cuts of rough machining and finishing machining. Rough machining and finishing machining may be performed under the same conditions or under different conditions.

Next, as shown in FIG. 6(b), the end face of the long side is machined using a compound cutting tool. The configuration of the composite cutting tool is as described in Section A above, and the conditions for end face machining with the composite cutting tool are as described above. By performing such end face processing, even if the workpiece is thick, the end face can be processed without any problems. Furthermore, cracks in the adhesive layer-attached polarizing plate (typically, the polarizer), staining of the cutting blade, and blocking can be suppressed. In addition, when a release liner and/or a surface protection film are temporarily attached to the adhesive layer-attached polarizing plate, lifting of these can be suppressed. When end milling the entire outer periphery of a polarizing plate with an adhesive layer using an end mill, uncut edges are often generated due to the cutting blade not coming into contact with the workpiece. When processing the entire outer periphery of a polarizing plate with an adhesive layer using a composite cutting tool, the processed end surface in the direction parallel to the absorption axis becomes vulnerable to impact due to heat shock, and cracks may occur. However, if the resin sheet does not contain a polarizer, such a problem will not substantially occur even if the entire outer periphery of the resin sheet is edge-processed using a composite cutting tool.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples. Evaluation items in Examples are as follows.

(1) Cracks The adhesive layer-attached polarizing plates obtained in Examples, Comparative Examples, and Reference Examples were attached to a glass plate (thickness: 1.1 mm) via the adhesive layer to prepare test samples.
(1-1) Cracks caused by heat shock test The above test sample was subjected to a heat shock test in which 30 minutes of holding at -40°C and then 30 minutes at 85°C were repeated, and the state of crack occurrence after the test was observed optically. Observation was made using a microscope (5x magnification). Specifically, the number and length (μm) of cracks were investigated and evaluated based on the following criteria.
A: The number is 10 or less, and the maximum length is 500 μm or less. B: The number is 10 or less, but the maximum length exceeds 500 μm. C: The number is more than 10, and the maximum length is 500 μm or less. (1-2) Cracks due to heating test exceeding 500 μm The above test sample was subjected to a heating test at 105° C. for 1000 hours and evaluated in the same manner as in (1-1).

(2) Floating The amount of floating of the surface protection film and release liner in the adhesive layer-attached polarizing plates obtained in Examples, Comparative Examples, and Reference Examples was measured using a magnifying glass or a microscope. The maximum value of the amount of floating in one workpiece was defined as the amount of floating, and evaluation was made based on the following criteria.
A: Floating amount is 300 μm or less B: Floating amount exceeds 300 μm and 500 μm or less C: Floating amount exceeds 500 μm

(3) Blade contamination The cutting blade of the composite cutting tool after end face processing in the example and the cutting blade of the end mill after end face processing in the comparative and reference examples were observed for contamination due to adhesive, and evaluated using the following criteria. did.
A: Substantially no contamination was observed. B: Contamination was observed, but no problems occurred in processing. C: Significant contamination was observed, and problems also occurred in processing.

(4) Blocking The states of the workpieces after end face processing in Examples, Comparative Examples, and Reference Examples were observed and evaluated based on the following criteria.
A: It was easy to separate the workpiece into individual polarizing plates with an adhesive layer. B: It was possible to separate the workpiece into individual polarizing plates with an adhesive layer, but the separation operation was difficult. C: The workpiece was completely block-shaped and it was impossible to separate it into individual polarizing plates with adhesive layers.

<Example 1>
By a conventional method, the composition of the surface protection film (60 μm) / cycloolefin protective film (47 μm) / polarizer (5 μm) / cycloolefin protective film (24 μm) / adhesive layer (20 μm) / release liner in order from the viewing side. A polarizing plate with an adhesive layer was produced. In addition, as the surface protection film, a surface protection film having a structure of PET base material (50 μm)/adhesive layer (10 μm) was used. This adhesive layer-attached polarizing plate was punched out to a size of 5.7 inches (approximately 140 mm in length and 65 mm in width). Here, punching was performed so that the absorption axis direction of the polarizer was in the horizontal direction (short side direction). A workpiece was made by stacking several punched polarizing plates with adhesive layers. The total thickness of the workpiece was 45 mm. While the obtained workpiece was held between clamps (jigs), the end face of the short side (in the absorption axis direction of the polarizer) was processed using an end mill. Specifically, using an end mill with an outer diameter of 9 mm, two blades, and a helix angle of 45°, each short side was subjected to two end face machining operations: rough machining and finish machining. The amount of scraping in the rough machining was 0.2 mm, and the amount of scraping in the finishing machining was 0.1 mm. In both rough machining and finishing machining, the feed rate of the end mill was 1,000 mm/min, and the rotation speed was 35,000 rpm. Next, the end face of the long side (in the direction orthogonal to the absorption axis direction of the polarizer) was processed using the composite cutting tool of the embodiment of the present invention. The composite cutting tool used was the end mill described above, in which a polishing part with a protruding height of 20 μm was provided on the relief surface of the cutting blade. The protruding surface of the polishing part was in the shape of a file (or a rotating grindstone) containing diamond particles. The distance L from the cutting edge of the cutting blade to the wall surface facing the rotating direction of the polishing section was 0.9 mm, and the relationship with the distance R1 from the rotation axis to the cutting edge was L=0.167×R1. The long side end face processing was performed twice under the same conditions. Specifically, the feed rate of the composite cutting tool was 1,000 mm/min, the rotation speed was 8,000 rpm, and the amount of one cutting was 0.1 mm. In this way, a polarizing plate with an adhesive layer was obtained. In end face machining, there was no need to precisely adjust the state in which the end mill and composite cutting tool were held in the machine tool, and uniform cutting was achieved over the entire thickness of the workpiece. The obtained polarizing plate with an adhesive layer was evaluated as described in (1) to (4) above. The results are shown in Table 1.

<Example 2>
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 60 mm. In end face machining, there was no need to precisely adjust the state in which the end mill and composite cutting tool were held in the machine tool, and uniform cutting was achieved over the entire thickness 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.

<Comparative example 1>
All sides (the entire outer periphery) of the workpiece formed in the same manner as in Example 1 were end-faced using only an end mill. Specifically, the entire outer periphery of the workpiece was subjected to two end face machining operations: rough machining and finishing machining in one stroke. The conditions for rough machining and finish machining were the same as in Example 1. Next, only the long sides were end-faced using a rotating grindstone (#400). The rotation speed of the rotary grindstone was 1,000 rpm, and the feed speed was 500 mm/min. In this way, a polarizing plate with an adhesive layer was obtained. When processing the end face of an end mill, a cutting defect occurred in a part of the workpiece (upper end or lower end in the thickness direction). Cutting defects were noticeable on 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.

<Reference example 1>
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 15 mm. No cutting defects were observed during end face machining. 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.

<Evaluation>
As is clear from Table 1, it can be seen that the composite cutting tool of the example of the present invention can cut even thick workpieces without any problems.

The composite cutting tool according to the embodiment of the present invention can be suitably used for manufacturing a resin sheet (particularly, end face processing in manufacturing). The resin sheet can be, for example, an optical film.

W Work 20 Compound cutting tool 21 Rotating shaft 22 Main body 23 Cutting blade 23a Cutting edge 23b Rake face 23c Relief face 24 Polishing part

Claims (1)

A main body that rotates around a rotation axis;
a cutting blade provided on the outer periphery of the main body and having a cutting edge, a rake surface, and a relief surface;
a polishing part provided as a protrusion having a file-like surface on a part of the relief surface of the cutting blade;
Composite cutting tool with.

Images