Attachment method of cutting blade and cutting unit

Abstract

To propose new techniques for an attachment method of a cutting blade and a cutting unit.SOLUTION: An attachment method of a cutting blade, which attaches the cutting blade having a through-hole formed at a center thereof to a tip of a spindle shaft, comprises a blade mount fixing step of fixing a blade mount to the tip of the spindle shaft, and a fixing step of fixing the cutting blade to the blade mount after executing the blade mount fixing step. The blade mount has a boss part that is inserted into the through-hole of the cutting blade and a flange part including an annular contact surface that protrudes from a rear end of the boss part to the outside in a radial direction to contact the cutting blade. A plurality of spraying ports that spray air are formed in a circumferential direction on an outer peripheral surface of the boss part. In the fixing step, the boss part is inserted into the through-hole of the cutting blade while the spraying ports spray the air to make the cutting blade adsorb to the annular contact surface.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a method for attaching a cutting blade and a cutting unit. [Background technology]

[0002] 2. Description of the Related Art Conventionally, as disclosed in, for example, Patent Document 1, cutting devices are known that cut a workpiece such as a semiconductor wafer with a cutting blade that rotates at high speed.

[0003] The cutting blade is fixed to the spindle, which rotates at high speed, by a blade mount and a fixing device, and a fixing device consisting of a blade mount and a fixing nut is used to fix a hub-type cutting blade, while a fixing device including a blade mount (rear flange), a front flange, and a fixing nut is used to fix a washer-type cutting blade.

[0004] Patent Document 1 proposes a fixing method in which the cutting blade is sucked and held by a blade mount, and a fixing nut is fastened in order to prevent the cutting blade from rotating when the cutting blade is attached.

[0005] Patent Document 1 describes that, as a defect caused by the rotation of the cutting blade when the cutting blade is attached, friction between the contact surface and the cutting blade may cause a part of the cutting blade to adhere to the contact surface or the contact surface to be scratched. It also describes that if the flatness of the contact surface is reduced due to foreign matter or scratches, the inclination of the cutting blade relative to the spindle and the eccentricity of the cutting blade during rotation will increase, resulting in a decrease in machining accuracy. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2020-194874 A Summary of the Invention [Problem to be solved by the invention]

[0007] When adopting a configuration involving suction as in Patent Document 1, there is a risk that mist in the machining chamber of the cutting device will also be sucked in when the cutting blade is held by suction with the blade mount. The mist contains fine dust and the like, and if the mist enters the air flow path for suction, it may cause rust or damage various sensors, so an improvement was eagerly desired.

[0008] In view of the above problems, the present invention proposes a new technique for a cutting blade mounting method and a cutting unit. [Means for solving the problem]

[0009] The problem to be solved by the present invention has been described above, and the means for solving this problem will now be described.

[0010] According to one aspect of the present invention, a method for mounting a cutting blade having a through hole formed in the center to the tip of a spindle shaft includes a blade mount fixing step for fixing a blade mount to the tip of the spindle shaft, and a fixing step for fixing the cutting blade to the blade mount after performing the blade mount fixing step, wherein the blade mount has a boss portion inserted into the through hole of the cutting blade, and a flange portion that protrudes radially outward from the rear end of the boss portion and includes an annular abutment surface that abuts against the cutting blade, and a plurality of nozzles for spraying air are formed in the circumferential direction on the outer peripheral surface of the boss portion, and in the fixing step, the boss portion is inserted into the through hole of the cutting blade while spraying air from the nozzles, thereby adsorbing the cutting blade to the annular abutment surface.

[0011] In addition, according to one aspect of the present invention, the method further includes an attachment step of, after performing the fixing step, fixing the cutting blade fixed to the blade mount to the blade mount with a fixing device, thereby clamping the cutting blade between the blade mount and the fixing device and attaching the cutting blade to the tip of the spindle shaft.

[0012] According to one aspect of the present invention, the injection port is formed so that air injected from the injection port is directed toward the annular contact surface.

[0013] Moreover, according to one aspect of the present invention, there is provided a cutting unit comprising a spindle and a fixing device for fixing a cutting blade to a tip of the spindle, the cutting blade having a through hole in the center, the cutting unit further comprising a blade mount having a boss portion inserted into the through hole of the cutting blade and a flange portion protruding radially outward from the rear end of the boss portion and including an annular abutment surface that abuts against the cutting blade, and a fixing device for clamping the cutting blade together with the blade mount, and the boss portion has a plurality of nozzles formed in the circumferential direction for spraying air from the outer circumferential surface of the boss portion.

[0014] According to one aspect of the present invention, the injection port is formed so that air injected from the injection port is directed toward the annular contact surface. Effect of the Invention

[0015] The present invention provides the following advantages. That is, according to one aspect of the present invention, when the cutting blade is fixed to the blade mount, air is sprayed from the nozzle, and the cutting blade can be attracted and fixed to the annular contact surface of the flange portion by the Bernoulli effect. And, since the cutting blade is attracted by the spray of air, there are no problems such as mist suction, rust, and sensor failure that occur when the cutting blade is held by conventional air suction. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram showing an embodiment of a cutting device suitable for implementing the present invention. [Diagram 2] FIG. 13 is a diagram showing an example of the configuration of a hub blade type cutting blade. [Diagram 3] FIG. 13 is a diagram showing an example of the configuration of a washer blade type cutting blade. [Figure 4] FIG. 2 is a diagram showing a cross-sectional configuration of a blade mount, etc. [Diagram 5] FIG. 13 is a diagram showing the state in which the blade mount is fixed to the spindle shaft. [Figure 6] FIG. 13 is a diagram showing how the blade mount is fixed to the spindle shaft. [Figure 7] FIG. 4 is a diagram showing an airflow caused by air from an injection port. [Figure 8] FIG. 4 is a diagram showing the state in which a cutting blade is attached. [Figure 9] FIG. 13 is a diagram showing another embodiment of the configuration of the ventilation path. [Figure 10] FIG. 13 is a diagram showing another embodiment of the configuration of the ventilation path. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Fig. 1 is a diagram showing one embodiment of a cutting device suitable for carrying out the present invention. In Fig. 1, the X-axis direction (machining feed direction, first horizontal direction, front-rear direction) and the Y-axis direction (indexing feed direction, second horizontal direction, left-right direction) are perpendicular to each other. The Z-axis direction (vertical direction, up-down direction, height direction) is perpendicular to the X-axis direction and the Y-axis direction.

[0018] 1, the cutting device 2 includes a base 4, and an elevator 6 including a lift platform 6a is provided at a front corner of the base 4. The elevator 6 includes a lift mechanism (not shown) and raises and lowers the lift platform 6a along the Z-axis direction.

[0019] A case 8 that houses various tools (parts, consumables, etc.) used by the cutting device 2, and a cassette 10 that houses a plurality of workpieces 11 to be cut by the cutting device 2 are placed on the lifting platform 6a of the elevator 6. Fig. 1 shows an example in which the case 8 is placed on the lifting platform 6a, and the cassette 10 is placed on the case 8.

[0020] The cassette 10 has a pair of side surfaces facing each other. A plurality of guide rails 10a are fixed to each side surface of the cassette 10 and are arranged at a predetermined interval along the height direction of the cassette 10. A frame unit (workpiece unit) 17 including the workpiece 11 is supported by the pair of guide rails 10a arranged at the same height position on both sides.

[0021] For example, the workpiece 11 is a disk-shaped wafer made of a semiconductor material such as silicon. The workpiece 11 is partitioned into a plurality of regions by a plurality of planned division lines (streets) arranged in a lattice pattern, and devices such as ICs and LSIs are formed on the front (upper) surface side of each of these regions. By cutting and dividing the workpiece 11 along the planned division lines, a plurality of device chips each equipped with a device are manufactured.

[0022] There are no limitations on the material, shape, structure, size, etc. of the workpiece 11. For example, the workpiece 11 may be a wafer made of a semiconductor other than silicon (GaAs, InP, GaN, SiC, etc.), glass, ceramics, resin, metal, etc. Furthermore, there are no limitations on the type, number, shape, structure, size, arrangement, etc. of devices formed on the workpiece 11, and no devices may be formed on the workpiece 11. Furthermore, the workpiece 11 may be a package substrate such as a CSP (Chip Size Package) substrate or a QFN (Quad Flat Non-leaded package) substrate.

[0023] A circular tape (dicing tape) 13 having a diameter larger than that of the workpiece 11 is attached to the back surface (lower surface) of the workpiece 11. The tape 13 may be a sheet having a circular film-like substrate and an adhesive layer (glue layer) provided on the substrate. For example, the substrate may be made of a resin such as polyolefin, polyvinyl chloride, or polyethylene terephthalate, and the adhesive layer may be made of an epoxy-, acrylic-, or rubber-based adhesive. The adhesive layer may be made of an ultraviolet-curable resin that is cured by irradiation with ultraviolet light.

[0024] The outer periphery of the tape 13 is attached to an annular frame 15 made of metal or the like and having a circular opening in the center. The diameter of the opening of the frame 15 is larger than the diameter of the workpiece 11, and the workpiece 11 is placed inside the opening of the frame 15.

[0025] When the tape 13 is attached to the workpiece 11 and the frame 15, the workpiece 11 is supported by the frame 15 via the tape 13. In this way, a frame unit 17 is formed including the workpiece 11, the tape 13, and the frame 15. Then, one or more frame units 17 are housed in the cassette 10.

[0026] An opening 4a is provided on the upper surface of the base 4 in an area adjacent to the elevator 6 in the X-axis direction. A cleaning unit 12 that cleans the workpiece 11 is disposed inside the opening 4a. The cleaning unit 12 includes a spinner table 14 that holds the workpiece 11, and a nozzle (not shown) that is disposed above the spinner table 14 and supplies a cleaning liquid such as pure water.

[0027] A rotation drive source (not shown), such as a motor, that rotates the spinner table 14 around a rotation axis that is approximately parallel to the Z-axis direction is connected to the spinner table 14. With the workpiece 11 held by the spinner table 14, the workpiece 11 is cleaned by supplying a cleaning liquid to the workpiece 11 from a nozzle while rotating the spinner table 14. Note that a gas-liquid mixed fluid in which a liquid (such as pure water) is mixed with air can also be used as the cleaning liquid.

[0028] A pair of guide rails 16 that hold a frame unit 17 are provided along the X-axis direction above the cleaning unit 12. A movement mechanism (not shown) that moves the pair of guide rails 16 toward and away from each other along the Y-axis direction is connected to the pair of guide rails 16. By sandwiching the frame unit 17 between the pair of guide rails 16, the position of the frame unit 17 in the Y-axis direction is adjusted.

[0029] A rectangular opening 4b is provided on the upper surface of the base 4 at a position adjacent to the guide rail 16 in the Y-axis direction. The opening 4b is formed so that its longitudinal direction is along the X-axis direction. A flat table cover 18 is disposed inside the opening 4b. In addition, bellows-shaped dust-proof and drip-proof covers 20 that are expandable and contractible in the X-axis direction are provided on both sides of the table cover 18 in the X-axis direction.

[0030] A holding table (chuck table) 22 for holding the workpiece 11, etc. is provided on the table cover 18. The upper surface of the holding table 22 forms a flat holding surface for holding the workpiece 11, etc. Also, a plurality of clamps 24 for gripping and fixing the frame 15, etc. are provided around the holding table 22.

[0031] For example, the holding table 22 has a cylindrical frame made of a metal such as stainless steel. A circular recess is formed on the upper surface side of the center of the frame, and a disk-shaped porous member made of a porous material such as porous ceramics is fitted into this recess. The holding surface of the holding table 22 is connected to a suction source such as an ejector via the porous member, a flow path provided inside the holding table 22, a valve, etc.

[0032] For example, the frame unit 17 is placed on the holding table 22 so that the front side of the workpiece 11 is exposed upward and the back side (the tape 13 side) of the workpiece 11 faces the holding surface of the holding table 22. In addition, the frame 15 is clamped by a plurality of clamps 24. In this state, when negative pressure from a suction source is applied to the holding surface of the holding table 22, the workpiece 11 is sucked and held by the holding table 22 via the tape 13.

[0033] Further, a pair of sub-tables 26 are provided adjacent to the holding table 22 on the table cover 18. The pair of sub-tables 26 are disposed on the rear side of the holding table 22 and spaced apart from each other in the Y-axis direction.

[0034] The upper surface of the sub-table 26 constitutes a flat holding surface for holding a plate-shaped member used for setting up, inspecting, evaluating, etc. the cutting process. For example, the holding surface of the sub-table 26 is formed in a rectangular shape, and is connected to a suction source such as an ejector via a flow path, a valve, etc. provided inside the sub-table 26. A dressing board (not shown) is held on this sub-table 26, and dressing is performed by cutting the cutting blade into the dressing board.

[0035] A moving unit and a rotary drive source (not shown) are provided below the table cover 18. The moving unit is composed of a ball screw type moving mechanism or the like that reads a scale to detect the position in the X-axis direction, and moves the holding table 22 and the sub-table 26 along the X-axis direction together with the table cover 18. The rotary drive source is composed of a motor or the like, and rotates the holding table 22 around a rotation axis that is approximately parallel to the Z-axis direction.

[0036] The front side of the opening 4b (the area adjacent to the opening 4a) corresponds to a transport area where the workpiece 11 is loaded and unloaded. The rear side of the opening 4b corresponds to a processing area where the workpiece 11 is processed. By moving the holding table 22 and the sub-table 26 along the X-axis direction by the moving unit, the holding table 22 and the sub-table 26 can be positioned in the transport area or the processing area.

[0037] A cover that constitutes a processing chamber 28 that defines a space in which the workpiece 11 is cut is provided above the processing area. In Fig. 1, the outline of the processing chamber 28 is indicated by a two-dot chain line. The processing chamber 28 is formed, for example, from metal or the like into a rectangular parallelepiped shape, and is disposed so as to cover the processing area. In addition, an entrance (opening) 28a through which the blade replacement device 100 can pass is provided on the side surface of the processing chamber 28 on the transfer area side.

[0038] A pair of cutting units 30 for cutting the workpiece 11 are provided inside the processing chamber 28 so as to face each other in the Y-axis direction. The cutting units 30 cut the workpiece 11 by rotating an annular cutting blade to cut into the workpiece 11. A cutting blade 36 is attached to each cutting unit 30. Each cutting unit 30 is configured to read scales by a Y-axis movement mechanism and a Z-axis movement mechanism (not shown) to detect its position in the Y-axis and Z-axis directions and move in the Y-axis and Z-axis directions.

[0039] An imaging camera 70 is disposed on each side of the pair of cutting units 30 to capture an image of the surface of the workpiece 11 held by the holding table 22 and align it with the cutting unit 30. The imaging camera 70 is, for example, a visible light camera equipped with an imaging element that receives visible light and converts it into an electrical signal, or an infrared camera equipped with an imaging element that receives infrared light and converts it into an electrical signal.

[0040] A first conveying unit 72 for conveying the workpiece 11 is provided above the base 4. A moving mechanism (not shown) for moving the first conveying unit 72 along the X-axis direction and the Y-axis direction is connected to the first conveying unit 72. The first conveying unit 72 is also equipped with an air cylinder, and the air cylinder incorporates a rod that moves up and down along the Z-axis direction.

[0041] A holding unit 72a that holds the frame 15 of the frame unit 17 and the like is fixed to the lower end of the rod of the air cylinder. For example, the holding unit 72a includes a plurality of suction pads that suck and hold the upper surface side of the frame 15 of the frame unit 17. In addition, a gripping mechanism 72b that grips the end of the frame 15 of the frame unit 17 and the like is provided on the end of the holding unit 72a on the elevator 6 side.

[0042] A second conveying unit 74 that conveys the workpiece 11 is provided above the holding unit 72a of the first conveying unit 72. A moving mechanism (not shown) that moves the second conveying unit 74 along the Y-axis direction is connected to the second conveying unit 74. The second conveying unit 74 also includes an air cylinder, and the air cylinder incorporates a rod that moves up and down along the Z-axis direction.

[0043] A holding unit 74a that holds the frame 15 of the frame unit 17 and the like is fixed to the lower end of the rod of the air cylinder. The configuration of the holding unit 74a is similar to that of the holding unit 72a of the first transport unit 72.

[0044] Further, an automatic replacement unit 76 for replacing the cutting blade 36 attached to the cutting unit 30 is provided on the side of the holding table 22. The automatic replacement unit 76 is configured to have a blade replacement device 100 at the tip of a robot arm 76a, and can automatically replace the cutting blade. Note that the present invention can also be applied to a cutting device that is configured without the automatic replacement unit 76.

[0045] A plate-shaped cover 78 is provided on the edge of the base 4 on the side of the automatic exchange unit 76. One end of the cover 78 is connected to the base 4 via a hinge 80, and the cover 78 is supported so as to be rotatable about the hinge 80 and is configured to be automatically opened and closed by a motor (not shown).

[0046] When the cutting unit 30 processes the workpiece 11, the cover 78 is in an upright state (open state) along the Z-axis direction as shown by the two-dot chain line in Fig. 1. On the other hand, when the automatic replacement unit 76 replaces the cutting blade 36, etc., the cover 78 is in a lying state (closed state) along the X-axis and Y-axis directions so as to cover the holding table, thereby protecting the holding surface of the holding table when the cutting blade, etc. is replaced.

[0047] The automatic replacement unit 76 is configured to automatically replace the cutting blade 36 by removing a used cutting blade 36 from the cutting unit 30 and attaching an unused or partially used (such as a second-hand) cutting blade 36 to the cutting unit 30.

[0048] The cutting blade is temporarily stored in a stock unit (not shown) housed in the case 8. When the cutting blade is replaced or the like, the stock unit (not shown) is appropriately pulled out of the case 8 by the first transport unit 72 and transported onto the closed cover 78. After the replacement or the like of the cutting blade is completed, the stock unit is housed in the case 8 by the first transport unit 72.

[0049] The operation of each movable part of the cutting device 2 shown in FIG. 1, the automatic replacement unit 76, etc. is controlled by a control device 82, so that cutting processing and replacement of the cutting blade are performed automatically.

[0050] Fig. 2 is a diagram showing the configuration of a cutting unit 30 equipped with a hub-type cutting blade. In Fig. 2, the direction in which the spindle shaft 31 protrudes from the spindle housing 39 is the front side, and the opposite side is the rear side.

[0051] As shown in Fig. 2, the tip of the spindle shaft 31 protrudes from the spindle housing 39. The spindle shaft 31 is rotated at high speed by a motor (not shown). A blade mount 32 is fixed to the tip of the spindle shaft 31 by a fixing bolt 34, and a cutting blade 36 is fixed to the blade mount 32 by a fixing nut 33. The cutting blade 36 in the example of Fig. 2 is configured as a hub-type hub blade in which a cutting edge 36b is formed on a hub base 36a. In this case, the fixing nut 33 functions as a fixing device for fixing the cutting blade 36 to the blade mount 32.

[0052] The blade mount 32 has a flange portion 32a formed on the rear side, and a cylindrical boss portion 32b that has an outer diameter smaller than that of the flange portion 32a and is formed further forward than the flange portion 32a.

[0053] A circular annular abutment surface 32c is formed on the front side of the flange portion 32a, and the rear surface of the hub base 36a of the cutting blade 36 abuts against this annular abutment surface 32c, so that the cutting blade 36 (hub base 36a) is held by being sandwiched between the fixing nut 33 and the annular abutment surface 32c.

[0054] On the rear side of boss portion 32b, injection ports 37, which will be described in detail later, are arranged at equal intervals in the circumferential direction. A threaded portion 32d is formed on the front side of boss portion 32b, and a threaded portion 33b formed in a through hole 33a of fixing nut 33 is screwed into this threaded portion 32d.

[0055] A through hole 32e penetrating in the front-rear direction is formed in the boss portion 32b, and the blade mount 32 is attached to the spindle shaft 31 by inserting the spindle shaft 31 into this through hole 32e. The blade mount 32 is fixed to the spindle shaft 31 by screwing a fixing bolt 34 through the through hole 32e into a screw hole portion 31a formed at the tip of the spindle shaft 31. A washer 34w is used together with the fixing bolt 34.

[0056] A through hole 36c is formed in the hub base 36a of the cutting blade 36, and the boss portion 32b of the blade mount 32 is inserted into this through hole 36c, thereby attaching the cutting blade 36 to the blade mount 32. The threaded portion 32d of the boss portion 32b protrudes forward through the through hole 36c of the cutting blade 36, and the threaded portion 32d is screwed into the threaded portion 33b of the fixing nut 33. In this way, the cutting blade 36 is fixed to the blade mount 32 by the fixing nut 33. When replacing the cutting blade, the fixing nut 33 is loosened and removed by the automatic replacement unit 76 (FIG. 1), and another cutting blade 36 is temporarily fixed to the blade mount 32, and then fastened to the blade mount 32 by the automatic replacement unit 76 again.

[0057] Fig. 3 is a diagram showing an example of a cutting unit having a washer-type cutting blade. In Fig. 3, the direction in which the spindle shaft 131 protrudes from the spindle housing 139 is the front side, and the opposite side is the rear side. The blade mount 132 has the same configuration as the blade mount 32 shown in Fig. 2, and detailed description thereof will be omitted.

[0058] As shown in Fig. 3, the tip of the spindle shaft 131 protrudes from the spindle housing 139. The spindle shaft 131 is rotated at high speed by a motor (not shown). A blade mount 132 is fixed to the tip of the spindle shaft 131 by a fixing bolt 134, and a cutting blade 136 is fixed to the blade mount 132 by a front flange 135 and a fixing nut 138. The cutting blade 36 in the example of Fig. 3 is configured as a washer-type washer blade without a hub base. In this case, the front flange 135 and the fixing nut 138 function as fixing devices for fixing the cutting blade 136 to the blade mount 132.

[0059] A through hole 136c is formed in the cutting blade 136, and the boss portion 132b of the blade mount 132 is inserted into this through hole 136c, thereby attaching the cutting blade 136 to the blade mount 132.

[0060] A circular annular abutment surface 135a is formed on the rear side of the front flange 135, and the rear surface of the cutting blade 136 abuts against this annular abutment surface 135a, so that the cutting blade 136 is held by being sandwiched between the front flange 135 and the abutment surface 132c of the blade mount 132.

[0061] The threaded portion 132d of the boss portion 132b of the blade mount 132 protrudes forward through a through hole 136c of the cutting blade 136, and further protrudes forward through a through hole 135c of the front flange 135. A fixing nut 138 is screwed onto the protruding threaded portion 132d. This fixes the cutting blade 136 and the front flange 135 to the blade mount 132 with the fixing nut 138. The boss portion 132b of the blade mount 132 is provided with an injection port 137 for injecting air.

[0062] Next, the configuration of the injection port provided on the blade mount will be described using an example of a cutting unit equipped with a hub-type cutting blade. 4, the blade mount 32 has a boss portion 32b that is inserted into a through hole 36c of the cutting blade 36, and a flange portion 32a that protrudes radially outward from the rear end of the boss portion 32b and includes an annular abutment surface 32c that abuts against the cutting blade 36. The cutting blade 36 is clamped between the blade mount 32 and a fixing nut 33 (fixing device).

[0063] A plurality of nozzles 37 for spraying air from an outer peripheral surface 32f of the boss portion 32b are formed in the circumferential direction of the boss portion 32b. The nozzles 37 are configured so that the air sprayed from the nozzles 37 is directed toward the annular abutment surface 32c formed on the flange portion 32a of the blade mount 32.

[0064] The injection port 37 communicates with a through hole 32e formed coaxially with the axis of the boss portion 32b via an air passage 32k.

[0065] The tapered portion 31v at the tip of the spindle shaft 31 is fitted into the rear tapered portion 32v of the through hole 32e, which is formed coaxially with the axis of the boss portion 32b, and a space portion 32p is formed between the through hole 32e and the front end face 31b of the spindle shaft 31.

[0066] A screw hole 31a is formed in the front end face 31b of the spindle shaft 31 coaxially with the axis of the spindle shaft 31, and a screw portion 34a of a fixing bolt 34 is screwed into this screw hole 31a. A head 34b of the fixing bolt 34 is pressed against a step 32g formed in a through hole 32e of the boss portion 32b via a washer 34w, and the blade mount 32 is fixed to the spindle shaft 31 as shown in FIG.

[0067] 4, in the fixing bolt 34, a shaft 34c is formed between the threaded portion 34a and the head 34b, and an air vent hole 34g is formed in the outer circumferential surface of the shaft 34c, which communicates with an air vent passage 34f provided in the threaded portion 34a. The air vent passage 34f communicates with an air vent hole 34h in the tip surface of the threaded portion 34a of the fixing bolt 34.

[0068] As shown in FIG. 5, when the blade mount 32 is fixed to the spindle shaft 31, a space 34k is formed between the shaft portion 34c of the fixing bolt 34 and the through hole 32e of the boss portion 32b.

[0069] 4, an air passage 31f communicating with the screw hole portion 31a is formed in the spindle shaft 31. The air passage 31f is connected to an air passage 39f formed in the spindle housing 39 and further to an air source 42 via a valve 41 disposed outside the spindle housing 39.

[0070] As shown in FIG. 5, when the blade mount 32 is fixed to the spindle shaft 31, a space 34m is formed between the fixing bolt 34 and the screw hole 31a.

[0071] 5, the nozzle 37 on the outer circumferential surface 32f of the boss portion 32b is connected to an air source 42 via air passage 32k, space 34k, air passage 34f, space 34m, air passage 31f, air passage 39f, and valve 41. By controlling the valve 41 with a control device (not shown), high-pressure air can be supplied from the air source 42 to the nozzle 37, causing air to be ejected from the nozzle 37.

[0072] Next, a method for attaching the cutting blade will be described. In the example shown in FIG. 6, a cutting blade 36 having a through hole 36c formed in the center is attached to the tip of a spindle shaft 31.

[0073] <Blade mount fixing step> As shown in Fig. 6, this is a step of fixing the blade mount 32 to the tip of the spindle shaft 31. Specifically, the tapered portion 31v formed at the tip of the spindle shaft 31 is fitted into the tapered portion 32v formed at the rear of the through hole 32e of the blade mount 32. Next, the fixing bolt 34 is threadedly inserted into the screw hole portion 31a of the spindle shaft 31, thereby fixing the blade mount 32 to the spindle shaft 31, as shown in Fig. 5.

[0074] <Fixation step> 7, after the blade mount fixing step is performed, this is a step of fixing the cutting blade 36 to the blade mount 32. At this time, the valve 41 is controlled to start the supply of air from the air source 42, and the boss portion 32b of the blade mount 32 is inserted into the through hole 36c of the cutting blade 36 while spraying air from the nozzle 37 formed in the boss portion 32b.

[0075] The air from the nozzle 37 is preferably sprayed toward the annular contact surface 32c, generating an airflow K between the cutting blade 36 and the annular contact surface 32c. Note that the direction of the air from the nozzle 37 is not particularly limited as long as the Bernoulli effect can be achieved by forming the airflow K that passes between the cutting blade 36 and the annular contact surface 32c and flows outward.

[0076] The timing at which air supply from the nozzle 37 begins can be, for example, before the tip of the boss portion 32b of the blade mount 32 is inserted into the through hole 36c of the cutting blade 36 (timing 1), before the hub base 36a reaches the nozzle 37 after insertion (timing 2), or after the rear surface of the hub base 36a abuts against the annular abutment surface 32c after insertion (timing 3).

[0077] The Bernoulli effect caused by the generation of the airflow K causes the rear surface 36d of the hub base 36a of the cutting blade 36 to be attracted to the annular contact surface 32c. The Bernoulli effect is generally known as "a phenomenon in which, when a fluid such as air or water flows with force, the pressure around the fluid decreases, attracting surrounding substances." The state of being attracted by the Bernoulli effect can also be expressed as a state in which the cutting blade 36 is provisionally fixed (temporarily fixed) to the blade mount 32.

[0078] <Installation steps> As shown in Figure 8, after performing the fixing step, the cutting blade 36 fixed to the blade mount 32 is fixed to the blade mount 32 with a fixing nut 33 which serves as a fixing device, thereby clamping the cutting blade 36 between the blade mount 32 and the fixing nut 33 and attaching the cutting blade 36 to the tip of the spindle shaft 31.

[0079] In this mounting step, the cutting blade 36 is attracted to the annular abutment surface 32c by the Bernoulli effect, so that when the fixing nut 33 is rotated and fastened, the cutting blade 36 is prevented from rotating together with the fixing nut 33. In other words, the cutting blade 36 is prevented from rotating together with the fixing nut 33, and it is possible to prevent the annular abutment surface 32c from being damaged by friction caused by the rotation, the annular abutment surface 32c from being damaged by rotating with a foreign object sandwiched on the surface of the annular abutment surface 32c, and the hub base 36a of the cutting blade 36 from being welded to the annular abutment surface 32c.

[0080] Furthermore, by preventing a decrease in flatness of the annular abutment surface 32c due to damage or foreign matter, the inclination of the cutting blade 36 relative to the spindle shaft 31 and the eccentricity of the cutting blade 36 during rotation can be kept low, preventing a decrease in processing accuracy.

[0081] As is clear from the above description, the present invention provides the following characteristic effects. That is, as shown in Fig. 8, the cutting blade 36 is attracted to the annular abutment surface 32c by the Bernoulli effect caused by the air flow K, so that the cutting blade 36 can be fixed so that the cutting edge of the cutting blade 36 forms a plane perpendicular to the rotation axis without being tilted relative to the annular abutment surface 32c. This allows the cutting edge of the cutting blade 36 to cut perpendicularly into the workpiece, ensuring high machining accuracy. Also, fluttering of the cutting edge due to the cutting blade 36 being tilted can be prevented.

[0082] The configuration of the present application is particularly suitable for an apparatus configuration in which the cutting blade 36 is automatically replaced by the blade replacement device 100 as shown in FIG. 1. That is, since the replacement of the cutting blade 36 is not checked by the operator, there is an increased possibility that the cutting blade 36 may be fixed at an angle or may fall off. In this respect, according to the configuration of the present application, the cutting blade 36 can be fixed by adsorption to the blade mount, so that the fixing failure can be effectively suppressed, and the problem of the cutting process being performed without detecting the fixing failure and damaging the workpiece can be avoided. Note that, in a configuration without using the blade replacement device 100 or without the blade replacement device 100, air may be sprayed from the nozzle when the operator manually replaces the cutting blade 36.

[0083] Furthermore, in the configuration of the present application, air is sprayed from the nozzle to generate the Bernoulli effect, so problems such as mist suction, rust, and sensor failure that occur in conventional devices that suck in and hold air do not occur.

[0084] In the above description, the cutting blade is a hub blade type as shown in FIG. However, the same applies to the washer type shown in FIG. 3, and the Bernoulli effect can be generated by injecting air from the injection port 137 in FIG.

[0085] FIG. 9 shows another embodiment of the configuration of the path to the nozzle 37. In FIG. In this embodiment, an air passage 31w communicating with a front end face 31b of the spindle shaft 31 is formed in the spindle shaft 31. As a result, the nozzle 37 on the outer peripheral surface 32f of the boss portion 32b is connected to the air source 42 via the air passage 32k, the space 34k, the space 32p, the air passage 31v, the air passage 39f, and the valve 41.

[0086] FIG. 10 shows another embodiment of the configuration of the path to the nozzle 37. In FIG. In this embodiment, no air passage is provided in the spindle shaft 31, but an air passage 39m and an annular groove 39n are provided in the spindle housing 39. Also, an air passage 32q in the front-rear direction is provided inside the blade mount 32, with its rear end opening facing the annular groove 39n and its front end communicating with the nozzle 37f. As a result, the nozzle 37f on the outer circumferential surface 32f of the boss portion 32b is connected to the air source 42 via the air passage 32q, the annular groove 39n, the air passage 39m, and the valve 41. [Explanation of symbols]

[0087] 2 Cutting equipment 30 Cutting unit 31 Spindle shaft 31a Screw hole 31b Front end surface 31f Ventilation passage 31w ventilation channel 32 Blade Mount 32a Flange part 32b Boss part 32c Annular contact surface 32d Threaded part 32e through hole 32f outer circumferential surface 32g stepped section 32k Ventilation 32p space part 32q Ventilation passage 33 Fixing nut 33a through hole 33b Threaded part 34 Fixing bolt 34a Threaded part 34b Head 34c shaft 34f Ventilation passage 34g Ventilation hole 34h Ventilation hole 34k space part 34m space 34w washer 36 Cutting Blade 36a Hub Base 36b cutting blade 36c through hole 36d rear 37 Nozzle 39 Spindle housing 39f Ventilation passage 41 Valve 42 Air source 76 Automated Exchange Unit 100 Blade Changer K Airflow

Claims

1. A method for mounting a cutting blade having a through hole formed in the center to a tip of a spindle shaft, comprising the steps of: a blade mount fixing step of fixing a blade mount to a tip of the spindle shaft; and a step of fixing the cutting blade to the blade mount after the step of fixing the blade mount is performed. the blade mount has a boss portion inserted into the through hole of the cutting blade, and a flange portion protruding radially outward from a rear end of the boss portion and including an annular abutment surface that abuts against the cutting blade, and a plurality of air outlets for injecting air are formed in the circumferential direction on the outer circumferential surface of the boss portion, In the fixing step, the boss portion is inserted into the through hole of the cutting blade while air is being sprayed from the spray port, thereby adsorbing the cutting blade to the annular contact surface. How to attach the cutting blade.

2. The method for mounting a cutting blade as described in claim 1, further comprising a mounting step of, after performing the fixing step, fixing the cutting blade fixed to the blade mount to the blade mount with a fixing device, thereby clamping the cutting blade between the blade mount and the fixing device and mounting the cutting blade to the tip of the spindle shaft.

3. 3. The method for attaching a cutting blade according to claim 1, wherein the nozzle is formed so that air jetted from the nozzle is directed toward the annular contact surface.

4. A cutting unit including a spindle and a fixture for fixing a cutting blade to a tip of the spindle, The cutting blade has a central through hole; The cutting unit includes a blade mount having a boss portion inserted into the through hole of the cutting blade and a flange portion protruding radially outward from a rear end of the boss portion and including an annular abutment surface that abuts against the cutting blade; a fixing device that clamps the cutting blade together with the blade mount, The boss portion has a plurality of nozzles formed in the circumferential direction for spraying air from the outer circumferential surface of the boss portion, the cutting unit.

5. 5. The cutting unit according to claim 4, wherein the nozzle is formed so that air jetted from the nozzle is directed toward the annular contact surface.

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