CN114786851A - End mill for cutting optical thin film and method for manufacturing optical thin film using the same - Google Patents

End mill for cutting optical thin film and method for manufacturing optical thin film using the same Download PDF

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CN114786851A
CN114786851A CN202080084399.XA CN202080084399A CN114786851A CN 114786851 A CN114786851 A CN 114786851A CN 202080084399 A CN202080084399 A CN 202080084399A CN 114786851 A CN114786851 A CN 114786851A
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China
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cutting
end mill
edge
thin film
optical
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土永诚
永谷勇人
中市诚
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Nitto Denko Corp
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Nitto Denko Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23C—MILLING
    • B23C3/00—Milling particular work; Special milling operations; Machines therefor
    • B23C3/12—Trimming or finishing edges, e.g. deburring welded corners
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23C—MILLING
    • B23C5/00—Milling-cutters
    • B23C5/02—Milling-cutters characterised by the shape of the cutter
    • B23C5/10—Shank-type cutters, i.e. with an integral shaft
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23C—MILLING
    • B23C5/00—Milling-cutters
    • B23C5/02—Milling-cutters characterised by the shape of the cutter
    • B23C5/10—Shank-type cutters, i.e. with an integral shaft
    • B23C5/1009—Ball nose end mills
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Milling Processes (AREA)
  • Polarising Elements (AREA)

Abstract

The invention provides an end mill capable of inhibiting burrs in cutting processing of an optical film. The end mill for cutting an optical thin film of the present invention includes a body that rotates about a rotation axis, and n cutting edges that protrude from the body and constitute the outermost diameter, and satisfies any one of the following (1) to (3): (1) n is 1; (2) n is 2 or more, and the maximum value of the difference between the edge lengths of all the cutting edges is 0.12% or less with respect to the reference edge length; or (3) n is 2 or more, and the minimum value of the difference between the edge length of the longest cutting edge and the edge lengths of the other cutting edges is 0.60% or more with respect to the reference edge length.

Description

End mill for cutting optical thin film and method for manufacturing optical thin film using the same
Technical Field
The present invention relates to an end mill for cutting an optical film and a method for manufacturing an optical film using the end mill.
Background
A technique of cutting an end face of an optical film (for example, a polarizing plate) is known. Typically, such cutting is performed by forming a workpiece by stacking a plurality of optical films and cutting the outer peripheral surface of the workpiece. In such cutting, a cutting tool having a plurality of cutting edges may be used. However, in cutting work using such a cutting tool, prevention or suppression of burrs (cutting defects or cutting residues) has been a continuing problem.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 2016-182658
Disclosure of Invention
Problems to be solved by the invention
The present invention has been made to solve the above conventional problems, and a main object thereof is to provide an end mill capable of suppressing burrs during cutting of an optical film.
Means for solving the problems
An end mill for cutting an optical thin film according to an embodiment of the present invention includes a body that rotates about a rotation axis and n cutting edges that protrude from the body and constitute the outermost diameter, and satisfies any one of the following (1) to (3): (1) n is 1; (2) n is 2 or more, and the maximum value of the difference between the edge lengths of all the cutting edges is 0.12% or less with respect to the reference edge length; or (3) n is 2 or more, and the minimum value of the difference between the edge length of the longest cutting edge and the edge lengths of the other cutting edges is 0.60% or more with respect to the reference edge length.
In one embodiment, the reference edge length is 0.5mm to 10 mm.
In one embodiment, the helix angle of the cutting edge is 0 °.
In one embodiment, the cutting edge is attached to the body.
In one embodiment, the end mill for optical film cutting has an outer diameter of less than 10mm and a length in the direction of the rotation axis of 15mm or more.
According to another aspect of the present invention, a method for manufacturing an optical film can be provided. The manufacturing method includes a step of forming a workpiece by overlapping a plurality of optical films, and a step of cutting an outer peripheral surface of the workpiece by using the end mill for optical film cutting.
In one embodiment, the cutting includes rough cutting and finish cutting.
In one embodiment, the depth of cut in the rough cutting is 0.2mm or less, the depth of cut in the finish cutting is 0.1mm or less, and the total depth of cut in the cutting is 0.3mm or less.
In one embodiment, the feed speed of the end mill for cutting an optical thin film during the cutting is 2000 mm/min or less, and the rotation speed is 8000rpm to 20000 rpm.
In one embodiment, the number of times of contact of the cutting edge of the end mill for cutting an optical thin film with respect to 100mm of the workpiece is 1800 times to 5000 times.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the embodiment of the present invention, an end mill capable of suppressing burrs in cutting an optical film can be realized by setting the number of cutting edges of the end mill to one, setting the maximum value of the difference between the edge lengths of all the cutting edges to a predetermined ratio or less with respect to the reference edge length for an end mill having a plurality of cutting edges, or setting the minimum value of the difference between the edge length of one cutting edge and the edge length of another cutting edge to a predetermined ratio or more with respect to the reference edge length for an end mill having a plurality of cutting edges.
Drawings
Fig. 1 (a) is a schematic plan view as viewed from the axial direction for explaining the structure of an end mill according to an embodiment of the present invention, and fig. 1 (b) is a schematic perspective view of the end mill of fig. 1 (a).
Fig. 2 is a schematic plan view as viewed from the axial direction for explaining the structure of an end mill according to another embodiment of the present invention.
Fig. 3 is a schematic plan view as viewed from the axial direction for explaining the structure of an end mill according to still another embodiment of the present invention.
Fig. 4 is a schematic plan view as viewed from the axial direction for explaining the structure of an end mill according to still another embodiment of the present invention.
Fig. 5 is a schematic plan view as viewed from the axial direction for explaining the structure of an end mill according to still another embodiment of the present invention.
Fig. 6 is a schematic plan view from the axial direction for explaining the structure of an end mill according to still another embodiment of the present invention.
Fig. 7 is a schematic plan view showing an example of the shape of an optical film subjected to nonlinear processing that can be obtained by a method for producing an optical film using an end mill according to an embodiment of the present invention.
Fig. 8 is a schematic perspective view for explaining a cutting process of an optical thin film using an end mill according to an embodiment of the present invention.
Fig. 9 (a) to 9 (e) are schematic plan views illustrating a series of steps of nonlinear cutting as an example of the cutting of the optical thin film by using the end mill according to the embodiment of the present invention.
Detailed Description
Specific embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. In addition, the drawings are schematically illustrated for easy observation, and the proportions, angles, and the like of the length, width, thickness, and the like in the drawings are different from those in reality.
A. End mill for cutting optical thin film
Fig. 1 (a) is a schematic plan view when viewed from the axial direction for explaining the structure of an end mill for optical thin film cutting (hereinafter, may be simply referred to as an end mill) according to an embodiment of the present invention, and fig. 1 (b) is a schematic perspective view of the end mill of fig. 1 (a). The end mill 100 illustrated in the drawing includes a body 20 that rotates about a rotation axis 22 extending in a vertical direction (a stacking direction of workpieces 200, which are objects to be cut on which optical films are stacked and which will be described later in detail), and a cutting edge 10 that protrudes from the body 20 and forms the outermost diameter. As the end mill, a straight end mill is representative. The helix angle of the cutting edge 10 may be 0 °, and the helix angle of the cutting edge 10 may also have a predetermined angle. In the example of the figure, the helix angle of the cutting edge 10 is 0 °. With such a configuration, the optical film can be cut satisfactorily. More specifically, in the case of cutting (for example, profile working or nonlinear working) using a cutting edge having a helix angle, the cutting surface may be tapered when viewed from the lateral direction, but by using a cutting edge having a helix angle of 0 °, the cutting surface can be prevented from being tapered. Particularly, when the optical thin film is subjected to fine nonlinear processing (profile processing) using a small-diameter end mill, a remarkable effect can be obtained. In the present specification, the term "helix angle of 0 °" means that the cutting edge 10a extends in a direction substantially parallel to the rotation axis 22, in other words, the cutting edge is not twisted with respect to the rotation axis. "0 °" means actually 0 °, and includes a case where the material is twisted by a slight angle due to a machining error or the like. In the present specification, "cutting" may be referred to as "cutting".
The cutting edge 10 may be formed integrally with the body 20 (i.e., the end mill may be formed by cutting out a single piece), or may be separately attached to the body 20. When the cutting blade 10 is independently attached to the body 20, it may be embedded in the body as shown in fig. 1 (a) or may be attached to the body as shown in fig. 2. The cutting edge 10 typically includes a tip 10a, a rake face 10b, and a flank face 10 c. The rake face 10b and the body 20 can define a groove 30. The shape of the flank surface 10c in plan view may be linear as in the illustrated example, may be curved (may have two flank surfaces), or may be smoothly curved. The flank surface 10c is preferably roughened. As the roughening treatment, any appropriate treatment can be adopted. As a representative example, the ejection process can be cited. By performing the roughening treatment on the flank face, in the case where the optical film includes an adhesive layer (e.g., an adhesive layer), adhesion of the adhesive or the adhesive to the cutting edge can be suppressed, and as a result, blocking can be suppressed. In the present specification, "blocking" refers to a phenomenon in which optical films are bonded to each other at the work by an adhesive or a bonding agent at the end surfaces when the optical films include a bonding layer, and the adhesive or the cutting dust of the adhesive attached to the end surfaces promotes the bonding of the optical films to each other.
In one embodiment, the cutting edge 10 comprises sintered diamond. With this configuration, fine cutting using a small-diameter end mill as described below can be performed satisfactorily.
The number of edges of the end mill may be 1, two, or 3 or more. The upper limit of the number of blades may be, for example, 6. The number of blades is preferably 1 to 3. In the embodiment of the present invention, a cutting edge having a specific configuration (to be described later in detail) can be employed in accordance with the number of edges. This is based on the following findings obtained after the inventors of the present invention have made an extensive study on the cause of the occurrence of burrs in cutting machining using an end mill having a plurality of cutting edges. For the sake of simplicity of description, a case where the cutting edges are two will be described. When the trajectories of the two cutting edges (the a edge and the B edge) during the cutting process are examined in detail, the trajectories of the a edge and the B edge are substantially the same when the edge lengths (the lengths of the protruding portions protruding from the body) of the a edge and the B edge are completely the same or when the difference between the two edge lengths is very small, and therefore the a edge and the B edge uniformly contact the workpiece, and the entire workpiece can be cut satisfactorily. However, when the edge lengths of the a blade and the B blade are different by a predetermined amount (for example, when the a blade is longer than the B blade by a predetermined amount), the trajectories of the a blade and the B blade intersect at a predetermined portion of the workpiece. As a result, the short B-edge contacts the workpiece only at a predetermined portion, and the cutting state of the workpiece is different from that of other portions at the predetermined portion. This causes cutting defects and cutting residues, resulting in burrs. On the other hand, if the difference in blade length between the a blade and the B blade exceeds a predetermined amount and becomes large (for example, if the a blade is significantly longer than the B blade), the trajectories of the a blade and the B blade are substantially concentric and do not intersect with each other. As a result, the short B blade does not contact the workpiece during the cutting process, and therefore the entire workpiece can be cut satisfactorily only by the a blade. This structure is practically equivalent to the case where the number of blades is 1.
Based on the above findings, when the number of blades is 1, burrs can be suppressed satisfactorily without using another special configuration.
When the number of cutting edges is two or more, the maximum value of the difference between the edge lengths of all the cutting edges is 0.12% or less with respect to the reference edge length in one embodiment, and thus the burr can be satisfactorily suppressed. In the present specification, the "reference length" refers to the longest edge length among the edge lengths of the plurality of cutting edges. For example, in the case where the number of blades is two, L is set to be L as shown in FIG. 1 (a)1And L2The difference with respect to the reference edge length (L)1Or L2The longer one) is set to 0.12% or less, the burr can be suppressed well. In addition, for example, when the number of blades is 3, the maximum value of the difference (i.e., L) among all the blade lengths is set as shown in fig. 41And L2、L1And L3And L1And L3The largest value of the difference) with respect to the reference edge length (L)1、L2Or L3The longest value in (d) is 0.12% or less, and burrs can be suppressed satisfactorily. The maximum value of the difference in edge length is preferably 0.10% or less, more preferably 0.08% or less, and ideally zero, with respect to the reference edge length. In the present embodiment, the difference in edge length between the plurality of cutting edges is reduced as much as possible. For example, when the reference blade length is 2.5mm, the maximum value of the blade length difference is 3 μm or less. Therefore, the blade length needs to be precisely measured, and such precise measurement enables the present embodiment. The precise measurement of the blade length can be realized, for example, by a three-dimensional shape measuring instrument combining a time-of-flight method and an interference method. Such three-dimensional shape measuring instruments are sold, for example, by XTIA corporation.
In another embodiment, when the number of edges is two or more, the minimum value of the difference between the edge length of the longest cutting edge and the edge length of the other cutting edge is 0.60% or more with respect to the reference edge length, whereby the occurrence of burrs can be favorably suppressedPuncturing. For example, in the case where the number of blades is two, L is set as shown in FIG. 51And L2The difference with respect to the reference edge length (L)1) The content of the burr is 0.60% or more, and the burr can be suppressed well. In addition, for example, when the number of cutting edges is 3, the minimum value of the difference between the edge length of the longest cutting edge and the edge lengths of the other cutting edges (i.e., L) is set as shown in fig. 61And L2And L1And L3The smaller one of the differences) with respect to the reference edge length (L)1) The burr can be suppressed well by setting the content to 0.60% or more. The minimum value of the difference in blade length is preferably 1.0% or more, more preferably 2.0% or more, and still more preferably 3.0% or more. The minimum value is, for example, 95% or less, or, for example, 90% or less. When the minimum value is within such a range, the end mill has less eccentricity than a case where the number of cutting edges is 1, and therefore the rotation of the end mill is more favorable, and as a result, an end mill having more excellent durability can be realized. When the minimum value is 100%, the equivalent configuration is obtained as when the number of blades is 1.
The reference edge length may be an edge length of a cutting edge most relevant to cutting. The reference blade length is preferably 0.5mm to 10mm, more preferably 0.7mm to 7mm, still more preferably 0.8mm to 5mm, and particularly preferably 1mm to 3 mm. When the reference edge length is within such a range, satisfactory cutting can be achieved.
The outer diameter of the end mill is preferably less than 10mm, more preferably 3mm to 9mm, and still more preferably 4mm to 7 mm. According to the embodiment of the present invention, for example, in the fine cutting process (in particular, the nonlinear process or the special-shaped process) using such a small-diameter end mill, burrs can be favorably suppressed. In the present specification, the term "outer diameter of the end mill" means twice the distance from the rotation axis 22 to the cutting edge 10 a.
The length of the end mill (actually, the cutting edge) in the direction of the rotation axis is preferably 15mm or more, and more preferably 20mm or more. The length of the cutting edge in the direction of the rotation axis is, for example, 120mm or less, preferably 100mm or less, and more preferably 50mm or less. If the length is such a length, in the case of cutting the optical thin film, the cutting can be performed on a workpiece on which a desired number of optical thin films are stacked, and therefore, the efficiency of the cutting can be improved. In this case, the cutting edge 10 is preferably of an integral structure having no joint along the longitudinal direction (the rotation axis direction) of the body 20. By making the cutting edge of an integral structure without a seam, the cutting ability, strength, and durability can be further improved.
B. Method for manufacturing optical film
A method for producing an optical film according to an embodiment of the present invention includes a step of cutting an end face of an optical film by using the optical film cutting end mill described in the above item a. More specifically, the manufacturing method includes a step of forming a work by stacking a plurality of optical films, and a step of cutting an end face of an optical film constituting the work by cutting an outer peripheral surface of the work. In one embodiment, the cutting process includes a non-linear process (a profile process).
Specific examples of the optical film include a polarizer, a retardation film, a polarizing plate (typically, a laminate of a polarizer and a protective film), a conductive film for a touch panel, a surface treatment film, and a laminate (for example, a circular polarizing plate for antireflection and a conductive layer-attached polarizing plate for a touch panel) obtained by appropriately laminating these materials according to the purpose. In one embodiment, the optical film includes an adhesive layer (e.g., an adhesive layer). According to the embodiment of the present invention, even in the optical film including the adhesive layer, burrs can be suppressed, and cutting can be performed satisfactorily.
Hereinafter, a method for producing a polarizing plate with an adhesive layer will be described as an example of an optical film. Specifically, the respective steps in the method for manufacturing a polarizing plate with an adhesive layer having a planar shape as shown in fig. 7 will be described. It is obvious to those skilled in the art that the optical film is not limited to the polarizing plate with an adhesive layer and the planar shape of the polarizing plate with an adhesive layer is not limited to the planar shape shown in fig. 7. That is, the production method of the present invention can be applied to any optical film having any shape.
B-1. formation of work
Fig. 8 is a schematic perspective view for explaining the cutting process of the optical film, and this figure shows a work 200. As shown in fig. 8, a work 200 in which a plurality of optical films (polarizing plates with adhesive layers) are stacked is formed. The adhesive layer-attached polarizing plate can be manufactured by a method conventionally known in the art, and therefore, a detailed description of the manufacturing method is omitted. The polarizing plate with an adhesive layer is typically cut into any suitable shape when a work is formed. Specifically, the polarizing plate with an adhesive layer may be cut into a rectangular shape, a shape similar to the rectangular shape, or a shape (e.g., circular shape) suitable for the purpose. In the illustrated example, the polarizing plate with an adhesive layer is cut into a rectangular shape, and the work 200 has outer peripheral surfaces (cut surfaces) 200a and 200b facing each other and outer peripheral surfaces (cut surfaces) 200c and 200d orthogonal to these. The workpiece 200 is preferably held from above and below by a holding mechanism (not shown). The total thickness of the workpiece is preferably 10mm to 50mm, more preferably 15mm to 25mm, and still more preferably about 20 mm. With such a thickness, damage due to pressing by the clamping mechanism or impact during cutting can be prevented. The polarizing plates with the adhesive layer are stacked so that the work pieces have such a total thickness. The number of polarizing plates with adhesive layers constituting the work may be, for example, 20 to 100. The clamping mechanism (e.g., a clamp) may be made of a soft material or a hard material. When the material is made of a soft material, the hardness (JIS a) is preferably 60 ° to 80 °. If the hardness is too high, an indentation by the clamping mechanism may remain. If the hardness is too low, positional deviation may occur due to deformation of the jig, and the cutting accuracy may become insufficient.
B-2. end milling cutter machining
Next, a predetermined position on the outer peripheral surface of the workpiece 200 is cut by the end mill 100. The end mill 100 is typically held by a machine tool (not shown), rotated at high speed about a rotation axis of the end mill, and used by being fed in a direction intersecting the rotation axis while being cut into the outer peripheral surface of the workpiece 200 by bringing a cutting edge into contact with the outer peripheral surface. That is, cutting is typically performed by bringing a cutting edge of an end mill into contact with the outer peripheral surface of the workpiece 200 and cutting the workpiece. In the case of manufacturing the adhesive layer-attached polarizing plate having the shape in plan view as shown in fig. 7, chamfered portions 200E, 200F, 200G, and 200H are formed at 4 corners of the outer periphery of the work 200, and a recess 200I is formed at a central portion of the outer peripheral surface connecting the chamfered portions 200E and 200H.
The cutting process of the work 200 will be described in detail. First, as shown in fig. 9 (a), the portion where the chamfered portion 200E of fig. 7 is formed is chamfered, and then, as shown in fig. 9 (b) to 9 (d), the portions where the chamfered portions 200F, 200G, and 200H are formed are chamfered in this order. Finally, as shown in fig. 9 (e), the recess 200I is formed by cutting. In the illustrated example, the chamfered portions 200E, 200F, 200G, and 200H and the recessed portion 200I are formed in this order, but they may be formed in any suitable order.
The cutting conditions can be appropriately set according to the structure of the polarizing plate with an adhesive layer, a desired shape, and the like. In one embodiment, the cutting includes rough cutting and finish cutting. The depth of cut by rough cutting is preferably 0.2mm or less. In rough cutting, the number of times the end mill cuts the cutting portion may be 1 time, 2 times, 3 times, or 3 times or more. For example, when 2 times of rough cutting is employed, the cutting depth per 1 time is preferably 0.1mm or less; when the rough cutting is performed 3 times, the cutting depth per 1 time is preferably 0.07mm or less. The cutting depth of the finish cutting is preferably 0.1mm or less. In the finish cutting, the number of cuts may be typically 1 cut. The total cutting depth of cutting is preferably 0.3mm or less. With the above-described configuration, burrs can be satisfactorily suppressed during cutting of the optical film.
The feed rate of the end mill during cutting is preferably 2000 mm/min or less, more preferably 500 mm/min to 1800 mm/min, and still more preferably 800 mm/min to 1500 mm/min. The rotation speed (rotation speed) of the end mill is preferably 8000rpm to 20000rpm, more preferably 10000rpm to 18000 rpm.
The number of times of contact of the cutting edge of the end mill with respect to 100mm cutting of the workpiece is preferably 1800 times to 5000 times, and more preferably 2000 times to 4000 times. If the number of times of contact is too small, the cutting resistance increases, and as a result, the life of the cutting edge may become short. If the number of contacts is too large, the effect of suppressing burrs may be insufficient. The number of times of contact can be adjusted by appropriately setting the number of cutting edges of the end mill, the feed rate and the rotation speed, and the minimum value of the difference in the edge length. In particular, according to the embodiment of the present invention, the number of times of contact can be reduced to such an extent that burrs can be suppressed by setting the minimum value of the difference in blade length to a predetermined value or more.
As described above, a polarizing plate with an adhesive layer can be obtained by cutting. In the illustrated example, an adhesive layer-attached polarizing plate including a non-linearly processed portion can be obtained.
[ examples ]
The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The evaluation items in the examples are as follows.
(1) Burrs of the tree
The cross sections of the work pieces (the adhesive layer-attached polarizing plates were stacked) obtained in examples and comparative examples were photographed by a camera. The shot data was subjected to image analysis, the area of the portion corresponding to the burr was calculated, and evaluation was performed according to the following criteria. Specifically, (i) the captured image is digitized in gray scale (black 0 to white 255), (ii) an object having a luminance of 100 or more and spanning 4 or more pixels adjacent to each other and an object having a luminance of 150 or more and spanning 2 to 3 or more pixels adjacent to each other are regarded as burrs, and (iii) the burrs are quantified by the sum of the areas (the number of pixels) of the portions regarded as burrs. In addition, the total area of the shot data was 3360mm2(area 525000).
Good: the burr area is 0.19mm2(corresponding to an area of 30) or less
The allowable: burr area over 0.19mm2And is 0.45mm2The following (corresponding to an area of 30 to 70)
Not allowed: burr area over 0.45mm2(corresponding to the excess area 70)
< production example 1> production of polarizing plate with adhesive layer
As the polarizing plate, a film (thickness 12 μm) obtained by uniaxially stretching a long polyvinyl alcohol (PVA) -based resin film in the longitudinal direction (MD direction) while containing iodine was used. An optical functional film (COP film with an antistatic layer) is adhered to one side of the polaroid. The antistatic-layer-attached COP film was a Cycloolefin (COP) film (25 μm) on which an antistatic layer (5 μm) was formed, and was laminated so that the COP film was on the polarizer side. A surface protection film was attached to the antistatic layer side of the laminate of the polarizer/COP film/antistatic layer obtained. On the other hand, a retardation film of a cycloolefin resin (product name "ZB-12" manufactured by japan rui-wen corporation, in-plane retardation Re (550) ═ 50nm, thickness 40 μm) was laminated on the polarizer side of the laminate. Further, an adhesive layer (thickness: 20 μm) was formed on the outer side of the retardation film, and a separator was bonded to the adhesive layer. Thus, a polarizing plate with an adhesive layer having a structure of a surface protective film, an antistatic layer, a COP film, a polarizer, a retardation film, an adhesive layer, and a separator was produced.
< example 1>
The polarizing plate with an adhesive layer obtained in production example 1 was punched out to have a size of 5.7 inches (about 140mm in the vertical direction and 65mm in the horizontal direction), and a plurality of the punched polarizing plates were stacked to prepare a work (about 20mm in total thickness). Polystyrene (PS) sheets were placed as spacers on both sides of the obtained work, and in a state of being held by a holder (jig), by cutting processing using an end mill, chamfered portions were formed at 4 corners of the outer periphery of the work, and further, a concave portion was formed at the central portion of 1 outer periphery among the 4 outer peripheries, and a polarizing plate with an adhesive layer subjected to nonlinear processing as shown in fig. 7 was obtained. Here, the end mill had two blades, a helix angle of 0 DEG and an outer diameter of 5 mm. The feed speed of the end mill was 1200 mm/min, and the rotation speed was 15000 rpm. Further, in the present embodiment, the edge length (reference edge length) L of the longer cutting edge of the two cutting edges is set to L1Set to 2.5mm, the reference blade length L1Edge length L from another cutting edge2The difference was set to 1.7 μm (relative to the reference edge length)Degree 0.07%). The burr of the polarizing plate with an adhesive layer (work) thus obtained was calculated in accordance with the procedure of (1) above. The results are shown in table 1.
< comparative example 1>
Except that L1And L2A non-linearly processed polarizing plate with an adhesive layer was obtained in the same manner as in example 1, except that the difference was 3.7 μm (0.15% with respect to the reference edge length). The burr of the polarizing plate with an adhesive layer (work) thus obtained was calculated in accordance with the procedure of (1) above. The results are shown in table 1.
< comparative example 2>
Except that L1And L2A nonlinear-processed polarizing plate with an adhesive layer was obtained in the same manner as in example 1, except that the difference was 10.7 μm (0.43% with respect to the reference blade length). The burrs of the polarizing plate with an adhesive layer (workpiece) thus obtained were calculated in accordance with the procedure of (1) above. The results are shown in table 1.
< comparative example 3>
Except that L1And L2A nonlinear-processed polarizing plate with an adhesive layer was obtained in the same manner as in example 1, except that the difference was 11.7 μm (0.47% with respect to the reference blade length). The burr of the polarizing plate with an adhesive layer (work) thus obtained was calculated in accordance with the procedure of (1) above. The results are shown in table 1.
< example 2>
Except that L1And L2A non-linearly processed polarizing plate with an adhesive layer was obtained in the same manner as in example 1, except that the difference was 127.7 μm (5.11% with respect to the reference blade length). The burr of the polarizing plate with an adhesive layer (work) thus obtained was calculated in accordance with the procedure of (1) above. The results are shown in table 1.
< example 3>
A non-linearly processed polarizing plate with an adhesive layer was obtained in the same manner as in example 1, except that the number of edges of the end mill was 3. In the present example, the edge length (reference edge length) L of the longest cutting edge among the 3 cutting edges was set to1Set to 2.5mm, and the blade lengths of the two cutting blades are set to L2(same length), mixing L1And L2The difference was set to 1.7 μm (0.07% with respect to the reference edge length). That is, the configuration corresponds to fig. 6. The burrs of the polarizing plate with an adhesive layer (workpiece) thus obtained were calculated in accordance with the procedure of (1) above. The results are shown in table 1.
< comparative example 4>
Except that L1And L2A nonlinear-processed polarizing plate with an adhesive layer was obtained in the same manner as in example 3, except that the difference was 10.7 μm (0.43% with respect to the reference blade length). The burrs of the polarizing plate with an adhesive layer (workpiece) thus obtained were calculated in accordance with the procedure of (1) above. The results are shown in table 1.
< example 4>
Except that L1And L2A nonlinear-processed polarizing plate with an adhesive layer was obtained in the same manner as in example 3, except that the difference was 127.7 μm (5.11% with respect to the reference blade length). The burr of the polarizing plate with an adhesive layer (work) thus obtained was calculated in accordance with the procedure of (1) above. The results are shown in table 1.
< example 5>
A non-linearly processed polarizing plate with an adhesive layer was obtained in the same manner as in example 1, except that the number of edges of the end mill was 1. The burr of the polarizing plate with an adhesive layer (work) thus obtained was calculated in accordance with the procedure of (1) above. The results are shown in table 1.
TABLE 1
Figure BDA0003678731660000121
As is apparent from table 1, according to the embodiments of the present invention, in an end mill having a plurality of cutting edges, burrs can be favorably suppressed in the cutting process of an optical film by setting the maximum value of the difference between the edge lengths of all the cutting edges to a predetermined ratio or less with respect to the reference edge length, or setting the minimum value of the difference between the edge length of one cutting edge and the edge length of another cutting edge to a predetermined ratio or more with respect to the reference edge length.
Industrial applicability of the invention
The end mill of the present invention can be applied to cutting of optical films. The optical film cut by the end mill of the present invention can be applied to, for example, a special-shaped image display unit represented by an automobile instrument panel or a smart watch.
Description of the reference numerals
10. A cutting edge; 10a, a blade tip; 10b, a rake face; 10c, a flank face; 20. a main body; 22. a rotating shaft; 30. a groove; 100. an end mill; 200. and (5) a workpiece.

Claims (10)

1. An end mill for cutting an optical thin film, comprising a body rotating about a rotation axis and n cutting edges projecting from the body and constituting the outermost diameter, and satisfying any one of the following (1) to (3):
(1) n is 1;
(2) n is 2 or more, and the maximum value of the difference between the edge lengths of all the cutting edges is 0.12% or less with respect to the reference edge length; or alternatively
(3) n is 2 or more, and the minimum value of the difference between the edge length of the longest cutting edge and the edge lengths of the other cutting edges is 0.60% or more with respect to the reference edge length.
2. The end mill for cutting an optical thin film according to claim 1,
the length of the reference blade is 0.5 mm-10 mm.
3. The end mill for cutting optical films according to claim 1 or 2,
the helix angle of the cutting edge is 0 °.
4. The end mill for cutting an optical thin film according to any one of claims 1 to 3,
the cutting edge is attached to the body.
5. The end mill for cutting an optical thin film according to any one of claims 1 to 4,
the end mill for cutting an optical thin film has an outer diameter of less than 10mm and a length in the direction of the rotation axis of 15mm or more.
6. A method for producing an optical film, wherein,
the method comprises a step of forming a workpiece by overlapping a plurality of optical films, and a step of cutting the outer peripheral surface of the workpiece by using the end mill for optical film cutting according to any one of claims 1 to 5.
7. The method of manufacturing an optical film according to claim 6,
the cutting includes rough cutting and finish cutting.
8. The method of manufacturing an optical film according to claim 7,
the cutting depth of the rough cutting is less than 0.2mm, the cutting depth of the fine cutting is less than 0.1mm, and the total cutting depth of the cutting is less than 0.3 mm.
9. The method for producing an optical film according to any one of claims 6 to 8, wherein,
the feed speed of the end mill for cutting the optical thin film during the cutting is 2000 mm/min or less, and the rotation speed is 8000rpm to 20000 rpm.
10. The method for producing an optical film according to any one of claims 6 to 9, wherein,
the number of times of contact of the cutting edge of the end mill for optical film cutting with respect to 100mm of the workpiece is 1800 to 5000 times.
CN202080084399.XA 2019-12-25 2020-07-21 End mill for cutting optical thin film and method for manufacturing optical thin film using the same Pending CN114786851A (en)

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