Machining device

Abstract

To provide a machining device that is able to prevent breakage of a spindle during machining.SOLUTION: A machining device 1 includes: a grinding unit 20 having a spindle housing 24 that rotatably supports a spindle 22 around an axis by means of an air bearing 26; a compressed air control unit 50 having a switching valve capable of switching between first compressed air 511 supplied from a first compressed air source 51 and a second compressed air 521 supplied from a second compressed air source 52; and a sensor that detects a pressure of the first compressed air 511 supplied from the first compressed air source 51 to an air supply path 263 of the spindle housing 24. When a value detected by the sensor falls below a predetermined threshold, the compressed air control unit 50 switches the first compressed air 511 supplied to the air supply path 263 of the spindle housing 24, to the second compressed air 521 supplied from the second compressed air source 52, by means of the switching valve.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a processing apparatus for processing a workpiece with a processing tool disposed on a spindle that rotates on an air bearing using compressed air. [Background technology]

[0002] There are various types of processing machines that hold workpieces such as semiconductor wafers and package substrates on a holding table and perform cutting, grinding, etc. In these processing machines, processing is performed by rotating a processing tool such as a grinding wheel disposed at the tip of a spindle.

[0003] The spindle is rotatably supported by a casing that surrounds the spindle via an air bearing, which is formed by supplying air (compressed air) into the gap between the outer surface of the spindle and the inner surface of the casing (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-042465 Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, the air is supplied from an air supply source (compressed air source) that is a utility facility in the factory where the processing equipment is installed. However, if the factory's air supply source stops due to some kind of malfunction, the air pressure used to support the spindle drops suddenly, causing the spindle to bite and break.

[0006] Therefore, in a processing device that processes a workpiece using a processing tool arranged on a spindle that rotates on an air bearing using air (compressed air), there is a problem of providing a processing device that will not bite and damage the spindle even if the air supply source (compressed air source) as a factory utility facility stops.

[0007] An object of the present invention is to provide a processing device that can prevent damage to a spindle during processing. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, the processing apparatus of the present invention is a processing apparatus for processing a workpiece, and includes a holding table for holding the workpiece, a spindle on the tip of which a processing tool can be disposed, and a casing that surrounds the outer surface of the spindle and rotatably supports the spindle by an air bearing, and includes a processing unit that processes the workpiece held by the holding table with the processing tool, and a processing unit that communicates with a first compressed air source through a first communication passage and with a second compressed air source through a second communication passage, and a compressed air control unit that has a switching valve capable of switching between the first compressed air and the second compressed air being supplied, and controls the supply of the first compressed air or the second compressed air to the casing; and a sensor that detects at least the pressure of the first compressed air supplied to the casing from the first compressed air source, wherein when the first compressed air supplied from the first compressed air source is supplied to the casing, if the value detected by the sensor falls below a predetermined threshold, the compressed air control unit switches the first compressed air to be supplied to the casing to the second compressed air supplied from the second compressed air source using the switching valve.

[0009] The processing apparatus may further include a control valve for controlling the flow rate of the first compressed air from the first compressed air source from the casing side to the first compressed air source side.

[0010] In the processing apparatus, the control valve may be a Tesla valve. [Effects of the Invention]

[0011] The present invention has the effect of suppressing damage to the spindle during machining. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view showing an example of the configuration of a processing device according to the first embodiment. [Figure 2] FIG. 2 is a side view, partly in section, schematically showing the configuration of the grinding unit of the processing apparatus shown in FIG. [Figure 3] FIG. 3 is a diagram schematically illustrating a state in which compressed air flows in the forward direction of the control valve of the processing apparatus shown in FIG. [Figure 4] FIG. 4 is a diagram schematically illustrating a state in which compressed air flows in the reverse direction of the control valve of the processing apparatus shown in FIG. [Figure 5] FIG. 5 is a diagram showing a state in which the switching valve of the processing apparatus shown in FIG. 1 supplies second compressed air from a second compressed air source to a casing. DETAILED DESCRIPTION OF THE INVENTION

[0013] Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the configuration can be made within the scope of the gist of the present invention.

[0014] [Embodiment 1] A processing apparatus according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an example of the configuration of the processing apparatus according to the first embodiment. FIG. 2 is a side view, partially in cross section, schematically showing the configuration of the grinding unit of the processing apparatus shown in FIG. 1. FIG. 3 is a diagram schematically showing a state in which compressed air flows in the forward direction of the control valve of the processing apparatus shown in FIG. 1. FIG. 4 is a diagram schematically showing a state in which compressed air flows in the reverse direction of the control valve of the processing apparatus shown in FIG. 1. FIG. 5 is a diagram showing a state in which the switching valve of the processing apparatus shown in FIG. 1 supplies second compressed air from a second compressed air source to a casing.

[0015] (Workpiece) 1 according to the first embodiment is a grinding apparatus that grinds (corresponding to processing) a workpiece 200. The workpiece 200 to be processed by the processing apparatus 1 according to the first embodiment is, for example, a disk-shaped semiconductor wafer having a substrate made of silicon, sapphire, gallium, SiC, or the like, or a wafer such as an optical device wafer. The workpiece 200 has a surface 201 divided into a grid pattern by a plurality of mutually intersecting planned division lines, and devices are formed in each of the regions.

[0016] The device is, for example, an integrated circuit such as an IC (Integrated Circuit) or an LSI (Large Scale Integration), an image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), or a memory (semiconductor storage device). A tape 210 having the same diameter as the workpiece 200 is attached to a front surface 201 of the workpiece 200, and a back surface 202 behind the front surface 201 is ground.

[0017] (Processing equipment) 1 according to the first embodiment is a grinding apparatus that grinds a back surface 202 of a workpiece 200. As shown in FIG. 1, the processing apparatus 1 includes an apparatus base 2, a holding table 10, a grinding unit 20, a processing feed unit 30, a grinding feed unit 40, a compressed air control unit 50, a sensor 60, and a control unit 100.

[0018] The holding table 10 holds the workpiece 200 with a holding surface 11 holding the front surface 201 side on which the device is formed, leaving the back surface 202 of the workpiece 200 exposed. The holding table 10 is disk-shaped, and the holding surface 11 that holds the workpiece 200 is made of porous ceramic or the like.

[0019] The holding table 10 has a holding surface 11 connected to a suction source (not shown), and the holding surface 11 is sucked by the suction source, thereby suction-holding the workpiece 200 placed on the holding surface 11. The holding table 10 is also rotatable about an axis parallel to the Z-axis direction by a rotation drive source (not shown). The Z-axis direction is parallel to the vertical direction (also referred to as the up-down direction) and is perpendicular to the holding surface 11. The holding table 10 suction-holds the workpiece 200 on the holding surface 11, and is rotated about the axis by the rotation drive source, thereby supporting the workpiece 200 so that it can rotate about the axis.

[0020] The grinding unit 20 is a processing unit that grinds the workpiece 200 held by the holding table 10 with a grinding wheel 21, which is a processing tool. The grinding unit 20 is supported by an erected pillar 3 erected from one end of the device base 2 in the Y-axis direction parallel to the horizontal direction, via a grinding feed unit 40.

[0021] As shown in Figure 2, the grinding unit 20 has a spindle 22 extending along the Z-axis direction, a spindle motor 23 that rotates the spindle 22 around its axis, a spindle housing 24 (corresponding to a casing) that supports the spindle 22 so that it can rotate around its axis, and a grinding wheel 21.

[0022] The spindle 22 is formed in a cylindrical shape with its axis aligned along the Z-axis direction, which is the up-down direction. The spindle 22 has a disk-shaped mount 221 at its lower end, which is the tip, on which the grinding wheel 21 can be attached. In other words, the spindle 22 can have the grinding wheel 21 mounted at its lower end.

[0023] In the first embodiment, as shown in Fig. 2, the spindle 22 has a cylindrical small diameter portion 222 and a cylindrical large diameter portion 223 that are coaxially arranged. In the first embodiment, the spindle 22 has two small diameter portions 222 and two large diameter portions 223. In the first embodiment, one of the large diameter portions 223 is attached to the mount 221, and one of the small diameter portions 222 is arranged between the large diameter portions 223, so that the large diameter portions 223 and the small diameter portions 222 are arranged alternately in the axial direction. In the first embodiment, the outer diameter of the large diameter portion 223 is equal to the outer diameter of the mount 221.

[0024] The spindle motor 23 is attached to the upper end (corresponding to the base end) of the spindle 22. In the first embodiment, the spindle motor 23 includes a rotor 231 attached to the outer peripheral surface of the other small diameter portion 222, and a stator 232 attached to the inner peripheral surface of the spindle housing 24 via a cooling jacket 25. When power is applied to the coil of the stator 232, the rotor 231, i.e., the spindle 22, rotates around the axis.

[0025] The cooling jacket 25 includes a cooling water passage 251 for circulating cooling water to cool the stator 232 of the spindle motor 23 and the like.

[0026] The spindle housing 24 is cylindrically formed and includes a cylindrical portion 241 that surrounds the outer peripheral surfaces of the small diameter portion 222 and the other large diameter portion 223 of the spindle 22, a disk-shaped disk portion 242 that closes the upper end of the cylindrical portion 241, and a spindle cover 243. The cylindrical portion 241 has an inner diameter larger than the outer diameter of the large diameter portion 223 of the spindle 22. The disk portion 242 has an outer diameter equal to the outer diameter of the cylindrical portion 241. The spindle housing 24 accommodates the small diameter portion 222 and the other large diameter portion 223 of the spindle 22 within the cylindrical portion 241 and supports the spindle 22 rotatably about its axis via an air bearing 26.

[0027] Air bearing 26 includes an annular intrusion portion 261 that intrudes between large diameter portions 223 of spindle 22, air outlets 262 that open to the upper surface, lower surface and inner circumferential surface of intrusion portion 261, and an air supply path 263 that is provided inside spindle housing 24 and communicates with air outlet 262. Intrusion portion 261 is provided integrally with cylindrical portion 241 on the inner circumferential surface of cylindrical portion 241, and has an inner diameter larger than the outer diameter of small diameter portions 222 and a thickness thinner than the distance between large diameter portions 223.

[0028] A plurality of air outlets 262 are provided at equal intervals in the radial and circumferential directions on the upper surface of the intrusion portion 261. A plurality of air outlets 262 are provided at equal intervals in the radial and circumferential directions on the lower surface of the intrusion portion 261. A plurality of air outlets 262 are provided at equal intervals in the circumferential direction on the inner peripheral surface of the intrusion portion 261.

[0029] The air supply path 263 is a passage provided inside the spindle housing 24, and is supplied with first compressed air 511 from the first compressed air source 51 or second compressed air 521 from the second compressed air source 52 via the compressed air control unit 50. The air bearing 26 ejects the compressed air 511, 521 supplied from the compressed air sources 51, 52 through the air supply path 263 and from the air ejection port 262, thereby supporting the spindle 22 rotatably about its axis.

[0030] The spindle cover 243 is formed in a cylindrical shape with inner and outer diameters equal to those of the spindle housing 24. The spindle cover 243 is attached to the lower end of the spindle housing 24 and accommodates one of the large diameter portions 223 of the spindle 22. In the first embodiment, the spindle cover 243 is disposed coaxially with the spindle housing 24.

[0031] The grinding wheel 21 is attached to the underside of the mount 221. The grinding wheel 21 includes a wheel base 211 formed in an annular shape and attached to the underside of the mount 221, and a plurality of grinding stones 212 arranged in an annular shape on the underside of the wheel base 211. The grinding stones 212 are arranged at equal intervals in the circumferential direction of the wheel base 211, and a plurality of grinding stones 212 are fixed to the underside of the wheel base 211.

[0032] The grinding wheel 212 is configured as a so-called segment grinding wheel formed into a single mass by mixing abrasive grains such as diamond or CBN (Cubic Boron Nitride) with a bonding material (also called a bond material) made of metal, ceramic, resin, etc. The grinding wheel 212 grinds the back surface 202 of the workpiece 200.

[0033] The processing feed unit 30 is installed on the device base 2, and moves the holding table 10 relative to the grinding unit 20 in the Y-axis direction, which is the processing feed direction parallel to the holding surface 11. By moving the holding table 10 in the Y-axis direction, the processing feed unit 30 moves the holding table 10 between a carry-in / out position where the workpiece 200 is carried in and out of the holding table 10 away from the grinding unit 20, and a processing position located below the grinding unit 20 where the workpiece 200 is ground by the grinding unit 20.

[0034] The grinding feed unit 40 is attached to an upright column 3 that stands upright from the device base 2, and is a moving unit that moves the grinding unit 20 in the Z-axis direction, which is the vertical direction perpendicular to the holding surface 11. The grinding feed unit 40 lowers the cylindrical holding member 28 attached to the spindle housing 24 of the grinding unit 20 to bring the grinding wheel 212 closer to the workpiece 200 held on the holding table 10 at the processing position, and raises the holding member 28 to move the grinding wheel 212 away from the workpiece 200 held on the holding table 10 at the processing position.

[0035] The machining feed unit 30 and the grinding feed unit 40 are equipped with a well-known ball screw that is rotatable around its axis, a well-known pulse motor that rotates the ball screw around its axis, and a well-known guide rail that supports the holding table 10 or the grinding unit 20 so that it can move freely in the X-axis or Z-axis direction.

[0036] The compressed air control unit 50 supplies first compressed air 511 from the first compressed air source 51 or second compressed air 521 from the second compressed air source 52 to an air supply path 263 provided in the spindle housing 24. The first compressed air source 51 is a facility in a factory where the processing apparatus 1 is installed, and supplies compressed air of 0.5 MPa (gauge pressure) to the air supply path 263 of the spindle housing 24. The second compressed air source 52 is a spare air tank filled with the second compressed air 521 and installed in the processing apparatus 1, etc., and supplies compressed air of 0.5 MPa (gauge pressure) to the air supply path 263 of the spindle housing 24.

[0037] The compressed air control unit 50 has a switching valve 53. The switching valve 53 is connected to the first compressed air source 51 via a first communication passage 512 and to the second compressed air source 52 via a second communication passage 522. The switching valve 53 is capable of switching between first compressed air 511 supplied from the first compressed air source 51 to the air supply passage 263 of the spindle housing 24 and second compressed air 521 supplied from the second compressed air source 52 to the air supply passage 263 of the spindle housing 24. In other words, the switching valve 53 switches between a state in which the first compressed air is supplied to the air supply passage 263 of the spindle housing 24 and a state in which the second compressed air is supplied to the air supply passage 263 of the spindle housing 24.

[0038] The sensor 60 detects the pressure of at least the first compressed air 511 supplied from the first compressed air source 51 to the air supply path 263 of the spindle housing 24. In the first embodiment, the sensor 60 is disposed between the compressed air control unit 50 and the air supply path 263, detects the pressure of the compressed air 511, 521 supplied from the compressed air control unit 50 to the air supply path 263, and outputs the detection result to the control unit 100.

[0039] The processing apparatus 1 also includes a control valve 70 that controls the flow rate of first compressed air 511 from the first compressed air source 51, which flows from the air supply path 263 of the spindle housing 24 to the first compressed air source 51. The control valve 70 is disposed in the first communication path 512, and is a Tesla valve-type check valve that includes a serpentine main flow path 71 and a loop portion 73 that connects adjacent bent portions 72 of the main flow path 71, as shown in FIGS. 3 and 4. In the first embodiment, as shown in FIG. 3, when the first compressed air 511 flows from the first compressed air source 51 toward the compressed air control unit 50, the control valve 70 allows the first compressed air 511 to flow in the forward direction (indicated by an arrow 701 in FIG. 3). In embodiment 1, as shown in FIG. 4, when first compressed air 511 flows from the compressed air control unit 50 toward the first compressed air source 51, the control valve 70 causes the first compressed air 511 to flow in the opposite direction (indicated by arrow 702 in FIG. 4).

[0040] In the control valve 70, the pressure loss when the first compressed air 511 flows in the forward direction 701 is smaller than the pressure loss when the first compressed air 511 flows in the reverse direction 702. In the control valve 70, the flow rate of the first compressed air 511 in the forward direction 701 is greater than the flow rate of the first compressed air 511 in the reverse direction 702. In the first embodiment, the control valve 70 sets the flow rate of the first compressed air 511 in the forward direction at 0.5 MPa (gauge pressure) to 428 L / min, and sets the flow rate of the first compressed air 511 in the reverse direction at 0.5 MPa (gauge pressure) to 186 L / min.

[0041] The apparatus also includes a thickness measuring device 80 for measuring the thickness of the workpiece 200 that is held by suction on the holding table 10 and is to be ground. The thickness measuring device 80 outputs the measurement result to the control unit 100.

[0042] The control unit 100 controls each of the above-mentioned components constituting the machining apparatus 1. That is, the control unit 100 causes the machining apparatus 1 to execute a machining operation on the workpiece 200. The control unit 100 is a computer that has an arithmetic processing device having a microprocessor such as a CPU (central processing unit), a storage device having a memory such as a ROM (read only memory) or RAM (random access memory), and an input / output interface device, and is capable of executing a computer program.

[0043] The arithmetic processing unit of the control unit 100 executes a computer program stored in the ROM on the RAM to generate control signals for controlling the machining device 1. The arithmetic processing unit of the control unit 100 outputs the generated control signals to each component of the machining device 1 via the input / output interface device. The control unit 100 is also connected to a display means (not shown) configured by a liquid crystal display device or the like for displaying the status and images of the machining operation, and to an input means used by the operator to register machining conditions. The input means is configured by at least one of a touch panel provided on the display means, a keyboard, or the like.

[0044] (Machining operation) Next, a description will be given of the processing operation of the processing device 1 according to embodiment 1. In the processing device 1 having the above-described configuration, an operator or the like places the front surface 201 side of the workpiece 200 before grinding on the holding surface 11 of the holding table 10 at the carry-in / out position via tape 210, and the control unit 100 receives the processing conditions input by the operator or the like. The processing device 1 starts the processing operation when the control unit 100 receives the instruction to start the processing operation input by the operator.

[0045] When the machining operation is started, the control unit 100 of the machining apparatus 1 controls the switching valve 53 to supply first compressed air 511 from the first compressed air source 51 to the air supply path 263 of the spindle housing 24, and drives the spindle motor 23 to start rotating the spindle 22 and the grinding wheel 21 about their axes. Also, when the machining operation is started, the control unit 100 of the machining apparatus 1 operates the suction source to suck and hold the front surface 201 of the workpiece 200 on the holding surface 11 of the holding table 10, thereby exposing the back surface 202 of the workpiece 200 upward. During the machining operation, the control unit 100 controls the machining feed unit 30 to move the holding table 10, which is sucking and holding the workpiece 200, to the machining position.

[0046] In the processing operation, the processing apparatus 1 rotates the holding table 10 about its axis while the control unit 100 measures the thickness of the workpiece 200 held on the holding table 10 at the processing position using the thickness gauge 80. In the processing operation, the control unit 100 supplies grinding water to the grinding wheel 21 of the grinding unit 20 and controls the grinding feed unit 40 to lower the grinding wheel 21 rotated about its axis. In the processing operation, the processing apparatus 1 brings the grinding stone 212 of the grinding wheel 21 rotated about its axis into contact with the back surface 202 of the workpiece 200 held on the holding table 10 rotating about its axis while supplying grinding water, and grinds the back surface 202 of the workpiece 200 with the grinding stone 212. Thus, in the first embodiment, the processing device 1 grinds the rear surface 202 of the workpiece 200 to thin the workpiece 200 to a predetermined thickness.

[0047] In the processing operation, when the workpiece 200 is thinned to a predetermined thickness by the grinding wheel 212, the control unit 100 controls the grinding feed unit 40 to raise the grinding wheel 21. In the processing operation, the control unit 100 stops the rotation of the holding table 10 around its axis.

[0048] During the processing operation, the control unit 100 of the processing device 1 controls the processing feed unit 30 to transport the holding table 10, which is holding by suction the workpiece 200 that has been ground, to the loading / unloading position, and then stops the suction holding of the holding table 10 at the loading / unloading position, thereby completing the processing operation.

[0049] In addition, in embodiment 1, during processing operation, when the control unit 100 detects that the value detected by the sensor 60 is below a predetermined threshold, the processing device 1 switches the first compressed air 511 supplied to the air supply path 263 of the spindle housing 24 to the second compressed air 521 supplied from the second compressed air source 52 to the air supply path 263 of the spindle housing 24 by the switching valve 53 as shown in Figure 5.

[0050] The predetermined threshold value is a value less than 0.5 MPa (gauge pressure) in gauge pressure in embodiment 1, and is 0.4 MPa (gauge pressure) in embodiment 1. In this way, when supplying first compressed air 511 supplied from first compressed air source 51 to air supply path 263 of spindle housing 24, if the value detected by sensor 60 is lower than the predetermined threshold value, compressed air control unit 50 switches first compressed air 511 supplied to air supply path 263 of spindle housing 24 to second compressed air 521 supplied from second compressed air source 52 by switching valve 53.

[0051] As described above, the processing apparatus 1 of embodiment 1 is equipped with a compressed air control unit 50 that is connected to the first compressed air source 51 and the second compressed air source 52, has a switching valve 53 that can switch between the first compressed air 511 supplied from the first compressed air source 51 and the second compressed air supplied from the second compressed air source 52, and controls the supply of the first compressed air 511 or the second compressed air 521 to the air supply path 263 of the spindle housing 24, and a sensor 60 that detects the pressure of at least the first compressed air 511 supplied from the first compressed air source 51 to the air supply path 263 of the spindle housing 24.

[0052] In addition, in the processing apparatus 1 of embodiment 1, when the compressed air control unit 50 supplies first compressed air 511 supplied from the first compressed air source 51 to the air supply path 263 of the spindle housing 24, if the value detected by the sensor 60 falls below a predetermined threshold, the first compressed air 511 supplied to the air supply path 263 of the spindle housing 24 is switched to second compressed air 521 supplied from the second compressed air source 52 by the switching valve 53.

[0053] For this reason, when the pressure of the first compressed air 511 from the first compressed air source 51 as factory equipment drops, the processing apparatus 1 of embodiment 1 can continuously supply compressed air to the air supply path 263 of the spindle housing 24 by switching to the second compressed air 521 from the second compressed air source 52.

[0054] As a result, the processing device 1 according to the first embodiment has the effect of being able to suppress damage to the spindle 22 during grinding.

[0055] Furthermore, when the first communication passage 512 connected to the first compressed air source 51 is connected to the air supply path 263 of the spindle housing 24 via the switching valve 53 of the compressed air control unit 50, if a malfunction such as a break occurs between the first compressed air source 51 in the first communication passage 512 and the control valve 70, without the control valve 70, the pressure in the first communication passage 512 would suddenly drop and the switching valve 53 would not be able to switch in time. However, the processing apparatus 1 of embodiment 1 is provided with the control valve 70 in the first communication passage 512, making it possible for the switching valve 53 to switch without the above-mentioned malfunction occurring.

[0056] In the processing apparatus 1 according to the first embodiment, the control valve 70 is a Tesla valve type check valve, and therefore the control valve 70 does not have any moving parts that move due to pressure fluctuations, thereby suppressing wear on the control valve 70. As a result, the processing apparatus 1 according to the first embodiment can suppress malfunction of the control valve 70, and the control valve 70 can control the flow rate of the first compressed air 511 of the first compressed air source 51 that flows from the air supply path 263 side of the spindle housing 24 to the first compressed air source 51 side.

[0057] The present invention is not limited to the above-described embodiment. In other words, various modifications can be made without departing from the gist of the present invention. In the present invention, the processing device 1 is not limited to a grinding device, but may be a processing device such as a cutting device, a polishing device, or a tool cutting device that has a spindle 22 that rotates around its axis and performs various processes on the workpiece 200. [Explanation of symbols]

[0058] 1 Processing equipment 10 Holding table 20 Grinding unit (processing unit) 21 Grinding wheels (machining tools) 22 Spindle 24 Spindle housing (casing) 26 Air bearing 50 Compressed air control unit 51 First compressed air source 52 Second compressed air source 53 Switching valve 60 sensors 70 Control valve 200 Workpiece 511 No. 1 Compressed Air 512 1st communication passage 521 Second compressed air 522 2nd communication passage

Claims

1. A processing device for processing a workpiece, a holding table for holding the workpiece; a machining unit having a spindle on the tip of which a machining tool can be mounted, and a casing surrounding the outer surface of the spindle and rotatably supporting the spindle by an air bearing, the machining unit machining the workpiece held by the holding table with the machining tool; a compressed air control unit that communicates with a first compressed air source via a first communication passage and with a second compressed air source via a second communication passage, has a switching valve that can switch between the first compressed air supplied from the first compressed air source and the second compressed air supplied from the second compressed air source, and controls the supply of the first compressed air or the second compressed air to the casing; a sensor that detects the pressure of the first compressed air supplied from at least the first compressed air source to the casing; Equipped with The compressed air control unit A processing apparatus characterized in that, when the first compressed air supplied from the first compressed air source is supplied to the casing, if the value detected by the sensor falls below a predetermined threshold, the first compressed air supplied to the casing is switched to the second compressed air supplied from the second compressed air source by the switching valve.

2. 2. The processing apparatus according to claim 1, further comprising a control valve for controlling the flow rate of the first compressed air from the first compressed air source from the casing side to the first compressed air source side.

3. 3. The processing apparatus according to claim 2, wherein the control valve is a Tesla valve.

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