Processing device with self-diagnosis function

Abstract

A processing device with a self-diagnosis function is provided, which self-diagnoses whether each component has changed. The processing device has a self-diagnosis unit that holds a workbench and diagnoses the state of the processing device when the processing unit is not processing, and the self-diagnosis unit has: a vibration source that gives the processing device vibrations with a vibration frequency within a specified range; a vibration sensor that observes the vibration propagating in the processing device and obtains a vibration waveform; a natural vibration frequency recording unit that records the vibration frequency that resonates in each component of the processing device as a natural vibration frequency; a frequency characteristic storage unit that stores the frequency characteristics of the vibration calculated based on the vibration waveform; and a determination unit that determines that there is a change in the component to which the vibration peak belongs when the difference between the vibration frequency of the vibration peak included in the frequency characteristics of the vibration and the natural vibration frequency of the component to which the vibration peak belongs exceeds a specified range.

Description

Technical Field

[0001] The present invention relates to a processing device having a self-diagnosis function and capable of self-diagnosing whether there is a change. Background Art

[0002] In the process of forming a device chip including a semiconductor device or an optical device from a workpiece made of silicon, sapphire, etc., various processing devices are used, such as a cutting device that divides the workpiece into individual devices, a laser processing device that performs laser processing, and a grinding device that grinds the workpiece to thin it to a predetermined thickness.

[0003] These processing devices include: a holding table that holds a workpiece; and a processing unit that processes the workpiece. Also, there are known mechanisms for rotating the holding table and the processing unit by a motor or the like, and mechanisms for rotating a ball screw by a motor or the like to move a slide to which the holding table and the processing unit are fixed (see Patent Documents 1 and 2).

[0004] When a processing device is used for a long time, wear and tear gradually develops in the components of the processing device. For example, the following changes occur: the nut becomes loose, or the groove of the ball screw becomes deeper. Due to these changes, the rotation or movement of the worktable and the processing unit also changes, and sometimes the specified results cannot be obtained in the processing of the processing device.

[0005] For example, when the groove of the ball screw used in the processing feed of the holding table is ground and deepened, the slider carrying the holding table will move due to a relatively light force, and the holding table is likely to move. In the processing device, in order to suppress the excessive movement of the holding table, the output of the motor is appropriately controlled, but when the slider moves due to a relatively light force, overshoot is likely to occur. Sometimes, when the position is controlled, the control of moving the holding table in the opposite direction according to the overshoot is repeatedly performed, which causes the holding table to vibrate in the front-back direction while moving.

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 62-173147

[0007] Patent Document 2: Japanese Patent Application Publication No. 2012-161861

[0008] When problems occur due to changes such as wear and tear of the components of such a processing device, the processing results are directly affected. Therefore, there is a problem of detecting the trend of changes in the components of the processing device and implementing countermeasures before problems occur.

[0009] However, it is not easy to detect the trend of changes in each component except for a limited number of operators with very high capabilities. Therefore, in reality, in most cases, it is impossible to implement countermeasures before the degree of change reaches an unacceptable level that affects the processing results. Summary of the invention

[0010] The present invention has been made in view of the above problem, and an object of the present invention is to provide a processing device having a self-diagnosis function capable of determining whether or not each component has changed.

[0011] According to one embodiment of the present invention, there is provided a processing device with a self-diagnosis function, the processing device comprising: a holding table for holding a workpiece; and a processing unit for processing the workpiece held by the holding table, characterized in that the processing device comprises a self-diagnosis unit for diagnosing the state of the processing device when the processing unit is not processing, and the self-diagnosis unit comprises: a vibration source for imparting vibrations of a vibration frequency within a specified range to the processing device; a vibration sensor for observing the vibrations generated by the vibration source and propagating in the processing device to obtain a vibration waveform; a natural vibration frequency recording unit for recording the vibration frequency that resonates in each component of the processing device as a natural vibration frequency; a frequency characteristic storage unit for storing the frequency characteristic of the vibration calculated based on the vibration waveform obtained by the vibration sensor; and a determination unit for determining that there is a change in the component to which the vibration peak belongs when the difference between the vibration frequency of a vibration peak included in the frequency characteristic of the vibration and the natural vibration frequency of the component to which the vibration peak belongs exceeds a specified range.

[0012] Preferably, the vibration source is an actuator having a servo motor, and the servo motor repeatedly rotates inversely to generate vibrations of the vibration frequency within the specified range. In addition, preferably, the servo motor rotates a ball screw or the holding table, and the ball screw moves the holding table or the processing unit.

[0013] Furthermore, it is preferred that the vibration sensor is an acceleration sensor.

[0014] A processing device according to one embodiment of the present invention has a self-diagnosis unit. The self-diagnosis unit has a vibration source and a vibration sensor. The vibration source can generate vibrations that propagate in the processing device, and the vibration sensor can observe the vibrations generated by the vibration source and propagated in the processing device to obtain a vibration waveform.

[0015] When a specific vibration is transmitted to each component of the processing device, resonance caused by the vibration occurs in each component. When the frequency characteristics of the vibration are calculated based on the vibration waveform acquired by the vibration sensor, a vibration peak caused by the resonance generated in each component appears in the frequency characteristics of the vibration. The vibration frequency that resonates in each component is called a natural vibration frequency, and each component has a different natural vibration frequency.

[0016] Therefore, each vibration peak appearing in the frequency characteristic of the vibration can be attributed to the resonance of the component that uses the vibration frequency as the natural vibration frequency. In addition, when changes such as loss occur in each component, the vibration frequency of the vibration peak appearing in the frequency characteristic of the vibration shifts.

[0017] The self-diagnosis unit includes: a natural vibration frequency recording unit, which records the vibration frequency that resonates in each component as the natural vibration frequency; and a determination unit. The determination unit compares the vibration frequency of the vibration peak included in the frequency characteristics of the vibration with the natural vibration frequency of the component to which the vibration peak belongs, and determines whether the component has changed based on the size of the difference. That is, when the difference exceeds a specified range, it is determined that there is a change in the component to which the vibration peak belongs.

[0018] Thus, in the processing device of one embodiment of the present invention, when changes occur in each component, the occurrence of the changes can be detected by the self-diagnosis unit. Therefore, before the changes increase and cause problems in the processing results, countermeasures for the changes can be studied and implemented.

[0019] Therefore, according to one aspect of the present invention, there is provided a processing device having a self-diagnosis function capable of determining whether or not each component has changed. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a perspective view schematically showing a processing device.

[0021] Figure 2 This is a side view schematically showing an example of a moving mechanism.

[0022] Figure 3 (A) is a side view schematically showing cleaning of the cleaning unit, Figure 3 (B) is a side view schematically showing generation of vibration in the washing unit.

[0023] Figure 4 (A) is a diagram schematically showing the frequency characteristics of vibration in a normal state where there is no change in each component. Figure 4(B) is a diagram schematically showing frequency characteristics of vibration when there is a change in the X-axis ball screw.

[0024] Figure 5 (A) is a diagram schematically showing the frequency characteristics of vibration in a normal state where there is no change in each component. Figure 5 (B) is a diagram schematically showing frequency characteristics of vibration when there is a change in the table base.

[0025] Description of symbols

[0026] 1: frame unit; 3: frame; 5: belt; 7: workpiece; 2: cutting device; 4: base; 4a, 4b, 4c: opening; 6: box support table; 8: box; 10: X-axis moving worktable; 12: dust and drip cover; 14: holding worktable; 14a: holding surface; 14b: fixture; 16: control unit; 16a: natural vibration frequency recording unit; 16b: frequency characteristic storage unit; 16c: determination unit; 18: vibration sensor; 22, 22a, 22b: cutting unit; 24: support structure; 28: Y-axis guide rail; 30: Y-axis moving plate; 32: Y-axis ball screw; 34: Y-axis pulse motor; 36: Z Axis guide; 38: Z-axis moving plate; 40: Z-axis ball screw; 42: Z-axis pulse motor; 48: camera unit; 50: cleaning unit; 52: cleaning workbench; 54: cleaning nozzle; 54a: cleaning liquid; 56: base; 58: X-axis moving mechanism; 60, 70b: servo motor; 62: X-axis ball screw; 64: holding workbench slider; 66: workbench base; 66a: θ-axis motor; 68a, 68b, 68c: vibration; 70a: rotating shaft; 72a, 72b: vibration waveform; 74, 78: natural vibration frequency; 76a, 76b, 80a, 80b: peak value; 82b: difference. DETAILED DESCRIPTION

[0027] An embodiment of one mode of the present invention is described with reference to the accompanying drawings. The processing device of this embodiment is a processing device used in a process of forming a device chip including a semiconductor device or an optical device from a workpiece composed of silicon or sapphire. The processing device is, for example, a cutting device that divides the workpiece into individual devices, a laser processing device that performs laser processing, a grinding device that grinds the workpiece to thin it to a predetermined thickness, or a tool cutting device that performs tool cutting.

[0028] Figure 1 It is a perspective view schematically showing a processing device according to this embodiment. Figure 1 The processing device shown is a cutting device that cuts a workpiece. In the following, in this embodiment, a case where the processing device is the cutting device 2 is described as an example.

[0029] The cutting device 2 has a base 4 for supporting various components. A rectangular opening 4a is formed at the front corner of the base 4, and a box support 6 for lifting and lowering is provided in the opening 4a. A box 8 for storing a plurality of frame units 1 is placed on the upper surface of the box support 6. Figure 1 In the figure, for the convenience of explanation, only the outline of the box 8 is shown.

[0030] The frame unit 1 includes: an annular frame 3; a belt 5 stretched on the opening of the annular frame 3; and a workpiece 7 supported on the upper surface of the belt 5. The workpiece 7 is a circular wafer formed of a semiconductor material such as silicon, and its front side is divided into a central device area and a peripheral remaining area surrounding the device area. The device area is further divided into a plurality of areas by predetermined dividing lines (spacers) arranged in a grid, and devices such as ICs and LSIs are formed in each area.

[0031] A belt 5 having a larger diameter than the workpiece 7 is attached to the back side of the workpiece 7. The outer peripheral portion of the belt 5 is fixed to the annular frame 3. That is, the workpiece 7 is supported by the annular frame 3 via the belt 5.

[0032] In addition, the workpiece 7 may be a workpiece other than a circular wafer formed of a semiconductor material such as silicon, and there is no limitation on the material, shape, structure, etc. of the workpiece 7. For example, a rectangular substrate formed of a material such as ceramic, resin, or metal may be used as the workpiece 7. There is no limitation on the type, number, and arrangement of the device.

[0033] The cutting device 2 is provided with a conveying mechanism (not shown) that takes out the frame unit 1 stored in the box 8 placed on the box support table 6 and places the frame unit 1 on the holding table 14 described later. According to the conveying mechanism, the frame unit 1 can also be stored in the box 8 after the cutting process is completed.

[0034] A rectangular opening 4b which is long in the X-axis direction (front-rear direction, processing feed direction) is formed on the side of the cassette support 6. An X-axis moving table 10 and an X-axis moving mechanism 58 (see FIG. 5 ) for moving the X-axis moving table 10 in the X-axis direction are arranged in the opening 4b. Figure 2 ) and a dust and drip proof cover 12 covering the X-axis moving mechanism 58.

[0035] A holding table 14 for holding the frame unit 1 is provided above the X-axis moving table 10. A porous member is provided on the upper surface of the holding table 14, and the upper surface of the porous member serves as a holding surface 14a for holding the frame unit 1. The holding table 14 has a clamp 14b on the outer periphery for clamping the frame unit 1 placed on the holding surface 14a.

[0036] The porous member is connected to a suction source (not shown) via a suction path (not shown) formed inside the holding table 14. When the frame unit 1 is placed on the holding surface 14a and the suction source is operated to apply negative pressure to the frame unit 1 through the suction path and the porous member, the frame unit 1 is sucked and held on the holding table 14.

[0037] A conveying unit (not shown) is provided near the opening 4b to convey the frame unit 1 to the holding table 14. The frame unit 1 conveyed by the conveying unit is placed on the holding surface 14a of the holding table 14, for example, with the upper surface side exposed upward. In addition, the conveying unit conveys the frame unit 1 after cutting to the cleaning unit 50 described later.

[0038] A gate-shaped support structure 24 for supporting two sets of cutting units 22a and 22b is arranged on the upper surface of the base 4 so as to span the opening 4b. A pair of Y-axis guide rails 28 parallel to the Y-axis direction are arranged on the upper front surface of the support structure 24. Two Y-axis moving plates 30 supporting the two sets of cutting units 22a and 22b are slidably mounted on the Y-axis guide rails 28.

[0039] A nut portion (not shown) is provided on the back side (rear surface side) of each Y-axis moving plate 30, and a Y-axis ball screw 32 parallel to the Y-axis guide rail 28 is screwed on the nut portion. A Y-axis pulse motor 34 is connected to one end of each Y-axis ball screw 32. When the Y-axis ball screw 32 is rotated by the Y-axis pulse motor 34, the Y-axis moving plate 30 moves in the Y-axis direction along the Y-axis guide rail 28.

[0040] A pair of Z-axis guide rails 36 parallel to the Z-axis direction is provided on the front surface (front face) of each Y-axis moving plate 30. A Z-axis moving plate 38 is slidably mounted on the Z-axis guide rails 36.

[0041] A nut portion (not shown) is provided on the back side (rear surface side) of each Z-axis moving plate 38, and a Z-axis ball screw 40 parallel to the Z-axis guide rail 36 is screwed on the nut portion. A Z-axis pulse motor 42 is connected to one end of each Z-axis ball screw 40. When the Z-axis ball screw 40 is rotated by the Z-axis pulse motor 42, the Z-axis moving plate 38 moves in the Z-axis direction along the Z-axis guide rail 36.

[0042] Cutting units 22a and 22b are provided at the lower part of each Z-axis moving plate 38. The cutting units 22a and 22b have an annular cutting tool mounted on one end side of a main shaft as a rotating shaft. The cutting units 22a and 22b have a cutting fluid supply unit for supplying cutting fluid to the cutting tool and the frame unit 1 held by the holding table 14. The cutting fluid is, for example, pure water.

[0043] In addition, a camera unit (photographing unit) 48 for photographing the workpiece 7, etc. is provided at a position adjacent to the cutting units 22a and 22b. When the Y-axis moving plate 30 is moved in the Y-axis direction, the cutting units 22a and 22b and the camera unit 48 are indexed and fed in the Y-axis direction. In addition, when the Z-axis moving plate 38 is moved in the Z-axis direction, the cutting units 22a and 22b and the camera unit 48 are raised and lowered.

[0044] use Figure 2 , an X-axis moving mechanism for moving the holding table 14 in the X-axis direction will be described. Figure 2 FIG. 1 is a side view schematically showing the X-axis moving mechanism. Figure 2 In the figure, the annular frame 3, the belt 5, the X-axis moving table 10, the dust and drip proof cover 12, the clamp 14b and the like are omitted.

[0045] The X-axis moving mechanism 58 is disposed on a base 56 at the bottom of the base 4 of the cutting device 2. The X-axis moving mechanism 58 includes an X-axis servo motor 60 and an X-axis ball screw 62, one end of which is connected to the X-axis servo motor 60. A nut portion for holding a table slider 64 is screwed onto the X-axis ball screw 62, and when the X-axis ball screw 62 is rotated by the X-axis servo motor 60, the table slider 64 is held and moved in the X-axis direction.

[0046] A table base 66 is placed above the holding table slider 64, and the holding table 14 is supported by the table base 66 via a θ-axis motor 66a. The θ-axis motor 66a rotates the holding table 14 around an axis in a direction perpendicular to the holding surface 14a.

[0047] When the workpiece 7 is cut, the workpiece 7 is held on the holding table 14 by the belt 5, the θ-axis motor 66a is operated, and the direction of the workpiece 7 and the processing feed direction are aligned using the camera unit 48. Then, the annular cutting tool mounted on the cutting unit 22 is rotated, the cutting unit 22 is lowered to a predetermined height, the X-axis moving mechanism 58 is operated, and the holding table 14 is processed and fed, so that the cutting tool cuts into the workpiece 7.

[0048] A circular opening 4c is formed at a position on the opposite side of the opening 4a relative to the opening 4b. A cleaning unit 50 for cleaning the frame unit 1 and the like after cutting the workpiece 7 is provided in the opening 4c. The cleaning unit 50 provided inside the opening 4c includes: a cleaning table 52, which functions as a holding table for holding the frame unit 1; and a cleaning nozzle 54, which sprays a cleaning liquid from above the frame unit 1 held by the cleaning table 52 to the frame unit 1. The cleaning liquid is, for example, pure water.

[0049] use Figure 3 (A) The cleaning unit 50 is described in detail. Figure 3 (A) is a side view schematically showing the cleaning process of the cleaning unit 50. Figure 3 (A) shows a cross-sectional view of the frame unit 1 carried into the cleaning unit 50 .

[0050] like Figure 3 As shown in (A), the cleaning unit 50 includes: a servo motor 70b, which serves as a rotation drive source for the cleaning workbench 52; and a rotating shaft 70a, which supports the cleaning workbench 52 and transmits the rotational force brought by the servo motor 70b to the cleaning workbench 52. A plurality of legs having a lifting mechanism are installed on the periphery of the servo motor 70b, for example. The lifting mechanism can lift the cleaning workbench 52.

[0051] When the workpiece 7 after cutting is cleaned by the cleaning unit 50, the frame unit 1 is first placed on the cleaning table 52, and the frame unit 1 is sucked and held on the cleaning table 52. Then, the servo motor 70b is operated to rotate the cleaning table 52. And, while the cleaning liquid 64a is sprayed downward from the cleaning nozzle 54, the cleaning nozzle 54 is moved above the frame unit 1 in a plane perpendicular to the rotation axis of the servo motor 70b.

[0052] like Figure 1As shown, the cutting device 2 has a control unit 16 for controlling the components of the cutting device 2. The components controlled by the control unit 16 are, for example, the box support table 6, the holding table 14, the cutting units 22a, 22b, the Y-axis pulse motor 34, the Z-axis pulse motor 42, the camera unit 48, the cleaning unit 50, and the X-axis moving mechanism 58. However, the components controlled by the control unit 16 are not limited thereto.

[0053] When the cutting device 2 is used for a long time, the wear of each component of the cutting device 2 gradually develops, and each component changes, and sometimes the predetermined result cannot be obtained in the processing of the cutting device 2. For example, when the groove of the X-axis ball screw 62 is ground and deepened, the holding table slider 64 on which the holding table 14 is mounted moves due to a relatively light force, and sometimes the holding table 14 is easy to move.

[0054] Therefore, in order to suppress the excessive movement of the holding table 14, the output of the X-axis servo motor 60 is appropriately controlled. However, when the holding table slider 64 moves due to a relatively light force, overshoot is likely to occur, and sometimes the control of moving the holding table 14 in the opposite direction according to the overshoot amount is repeatedly performed when controlling the position. And, as a result, the holding table 14 vibrates in the front-back direction while moving, sometimes having an adverse effect on the processing result. When a problem occurs due to changes in wear and tear, etc., it directly affects the processing result, so the cutting device 2 also has a self-diagnosis unit for diagnosing the state of the cutting device 2.

[0055] The self-diagnostic unit has, for example, a vibration source that imparts vibrations of a frequency within a specified range to a cutting device (processing device) 2, and a vibration sensor that observes the vibrations emitted by the vibration source and propagated in the cutting device 2 to obtain a vibration waveform.

[0056] The vibration source may be provided at any position of the cutting device 2 only for generating the vibration. The cutting device 2 may include a plurality of actuators for rotating or moving each component, and the actuators may be used as the vibration source of the self-diagnosis unit.

[0057] For example, the actuator used as the vibration source is the X-axis servo motor 60 of the X-axis moving mechanism 58. When the X-axis servo motor 60 is operated and repeatedly reverses its rotation, the X-axis ball screw 62 rotates while repeatedly reverses its rotation, and the holding table slider 64 moves back and forth in the X-axis direction. Vibration is generated along with this movement, and the vibration propagates inside the cutting device 2.

[0058] At this time, the vibration frequency of the vibration can be adjusted by changing the frequency of the reverse rotation of the X-axis servo motor 60 , and then, a vibration with a vibration frequency within a predetermined range is generated and propagated inside the cutting device 2 .

[0059] The vibration sensor for observing the vibration is appropriately selected from a displacement sensor, a velocity sensor, an acceleration sensor, etc. For example, it is a piezoelectric element, an AE sensor, or a MEMS sensor. Figure 1 and Figure 2 An example of the location where the vibration sensor is installed is shown in FIG. Figure 1 As shown, the vibration sensor 18 is provided on, for example, the cutting units 22a, 22b, the front surface of the support structure 24, or the upper surface of the support structure 24. Figure 2 As shown, the vibration sensor 18 is disposed on a base 56 or a workbench base 66 or the like.

[0060] Regarding the vibration sensor, when the vibration propagates to the vibration sensor, the relationship between the intensity (displacement, velocity or acceleration, etc.) of the vibration and time is obtained, for example, as a vibration waveform. And, when the vibration waveform is analyzed using a method such as a high-speed Fourier transform (FFT), the relationship between the intensity of the vibration and the vibration frequency (frequency) of the vibration is calculated as a frequency characteristic. Alternatively, the calculation can also be performed by scanning the vibration frequency of the vibration emitted from the vibration source, and plotting the relationship between the intensity of the vibration observed by the vibration sensor and the vibration frequency of the vibration emitted from the vibration source, thereby performing the calculation.

[0061] The vibration source and the vibration sensor 18 are connected to the control unit 16 of the cutting device 2 and controlled by the control unit 16. The vibration source vibrates according to the instruction of the control unit 16, and the vibration sensor 18 sends the vibration waveform obtained by observing the vibration to the control unit 16 according to the instruction of the control unit 16.

[0062] When the vibration propagates to each component of the cutting device 2, when the vibration frequency of the vibration is a specific value, resonance occurs in the component. The vibration frequency of the vibration when the resonance occurs is called the natural vibration frequency. The natural vibration frequency is determined by the shape, material, mass, etc. of the component, and each component has a different natural vibration frequency. In each component, vibrations of vibration frequencies other than the natural vibration frequency are easily attenuated, and vibrations of the natural vibration frequency are suppressed from attenuating by resonance.

[0063] Therefore, when a vibration of a frequency within a predetermined range is generated by a vibration source, and the vibration is observed by a vibration sensor to obtain a vibration waveform, thereby calculating a frequency characteristic of the vibration represented by the vibration frequency on the horizontal axis and the vibration intensity on the vertical axis, a vibration peak of a vibration frequency corresponding to the natural vibration frequency appears in the frequency characteristic of the vibration. With respect to the vibration peak, when a change such as loss occurs in the component to which it belongs, the vibration frequency shifts. The self-diagnosis unit determines whether each component has changed using the magnitude of the vibration frequency of the vibration peak that appears in the frequency characteristic of the vibration relative to the natural vibration frequency shift.

[0064] First, when each component is in a normal state, a vibration is generated by a vibration source, and the vibration propagated in the cutting device 2 is observed by a vibration sensor, the vibration waveform is obtained, the frequency characteristics of the vibration are calculated, and the vibration frequency of the vibration peak is recorded as the natural vibration frequency of each component. Then, after the cutting device 2 is operated, vibration is generated again by the vibration source, and the frequency characteristics of the vibration are calculated. And, when the vibration frequency of the vibration peak appearing in the frequency characteristics of the vibration is offset from the natural vibration frequency, it is detected that the component to which the vibration peak belongs has a change relative to the normal state.

[0065] This self-diagnostic unit further includes a natural frequency recording unit and a frequency characteristic storage unit in the control unit 16. The natural frequency recording unit 16a records the vibration frequency that resonates in each component of the cutting device (processing device) 2 as a natural frequency.

[0066] In order to know the natural vibration frequency of each component, for example, a hammer test can be implemented to give each component a physical impact to make it vibrate. The component of the object whose natural vibration frequency is desired to be calculated is impacted using a prescribed method, and the generated vibration is observed using an arbitrary vibration sensor 18. In this case, the vibration peak of the natural vibration frequency of the component of the object mainly appears in the frequency characteristics of the vibration. Therefore, the vibration frequency of the vibration peak is recorded as the natural vibration frequency of the component in the natural vibration frequency recording unit 16a. The frequency characteristic storage unit 16b records and stores the frequency characteristics of the vibration calculated based on the vibration waveform obtained by the vibration sensor 18.

[0067] When vibration propagates in the cutting device 2, the vibration waveform changes greatly depending on which actuator is used as the vibration source to operate and which vibration sensor 18 is used to observe the vibration. For example, when the vibration waveform is acquired using a vibration source and a vibration sensor 18 that are relatively close to the component being monitored for changes, it is easy to clearly see the peak value of the resonance in the component in the frequency characteristics of the vibration, and it is easy to capture whether the component has changed.

[0068] Therefore, the actuator used as the vibration source of the vibration and the vibration sensor 18 used in the observation may be stored in the frequency characteristic storage unit 16 b together with the frequency characteristics of the vibration.

[0069] The self-diagnosis unit further includes a determination unit in the control unit 16. The determination unit 16c has a function of determining whether a change such as loss has occurred in each component of the cutting device 2. The determination unit 16c determines that there is a change in the component to which the vibration peak belongs, when the difference between the vibration frequency of the vibration peak included in the calculated frequency characteristics of the vibration and the natural vibration frequency of the component to which the vibration peak belongs exceeds a predetermined range.

[0070] Next, the determination in the self-diagnosis unit will be described. Here, the following case will be described as an example: the actuator serving as the vibration source is the X-axis servo motor 60 (see Figure 2 ), the vibration sensor 18 (refer to Figure 2 ) is used for observing vibration and determining whether there is any change in the X-axis ball screw 62. In this case, the X-axis servo motor 60 is repeatedly driven in reverse direction to generate vibration 68a along the X-axis direction in the holding table slider 64.

[0071] Figure 4 (A) is a diagram schematically showing the frequency characteristics of vibration when each component is in a normal state. Figure 4 (A) shows a frequency characteristic 72a before a change occurs in the X-axis ball screw 62. The frequency characteristic 72a is calculated from a vibration waveform acquired at a predetermined timing such as before the operation of the cutting device 2 or immediately after maintenance.

[0072] Each frequency characteristic shown in this embodiment is represented by a chart with the horizontal axis being the logarithmic axis of the vibration frequency (Hz) and the vertical axis being the vibration intensity (arbitrary unit). Figure 4 As shown in (A), in the frequency characteristic 72a, vibration peaks appear at a plurality of vibration frequencies (Hz). Each vibration peak indicates that resonance has occurred in the component to which the vibration peak belongs.

[0073] For example, information that the natural vibration frequency of the X-axis ball screw 62 is about 400 Hz is obtained through a hammer test, and this information is registered in the natural vibration frequency recording unit 16 a. In this case, in the frequency characteristic 72 a, the vibration peak 76 a that appears near the natural vibration frequency 74 of the X-axis ball screw 62, that is, 400 Hz, is attributed to the X-axis ball screw 62.

[0074] Then, in Figure 4 (B) shows the frequency characteristics obtained after the operation of the cutting device 2 is repeated and when there is a change in a part of the components. Figure 4 (B) is a diagram schematically showing the frequency characteristics of vibration when there is a change in the X-axis ball screw 62. Figure 4 The frequency characteristics 72b and Figure 4 As can be seen from the comparison with the frequency characteristic 72a shown in (A) of FIG. 7 , in the frequency characteristic 72b , the vibration peak 76b attributed to the X-axis ball screw 62 is shifted from the natural frequency 74 to the high vibration frequency side.

[0075] At this time, when the change of the X-axis ball screw 62 is within the allowable range and the difference 82b between the vibration frequency of the vibration peak 76b and the natural vibration frequency 74 falls within the allowable prescribed range, the determination unit 16c determines that there is no change in the X-axis ball screw 62. On the other hand, when the change of the X-axis ball screw 62 exceeds the allowable range and the difference 82b exceeds the prescribed range, the determination unit 16c determines that there is a change in the X-axis ball screw 62 to which the vibration peak 76b belongs.

[0076] In addition, the prescribed range of the difference value 82b used in the determination of the presence or absence of a change can be appropriately set for each component. For example, it is set to the range of the difference value 82b that appears when the change of the component increases to a degree that causes an adverse condition in the processing of the cutting device (processing device) 2. Or it is set to the range of the difference value 82b that appears when the change of the component increases to a degree that is expected to cause an adverse condition in the processing soon and it is considered necessary to take corrective measures for the component before the adverse condition occurs.

[0077] use Figure 5 Another example of determination by the determination unit 16c is described. Here, the case of determining whether or not there is a change in the table base 66 is described as an example. As in the above example, the actuator serving as the vibration source is the X-axis servo motor 60 of the X-axis moving mechanism 58, and the vibration sensor 18 fixed to the table base 66 is used for vibration observation. In this case, the X-axis servo motor 60 is repeatedly driven in reverse, and vibration 68a along the X-axis direction is generated in the table slider 64.

[0078] Figure 5 (A) is a diagram schematically showing the frequency characteristics of vibration of each component in a normal state. Figure 5(A) shows the frequency characteristic 72c before the change occurs in the table base 66. For example, information that the natural vibration frequency of the table base 66 is about 180 Hz is obtained through a hammer test, and this information is registered in the natural vibration frequency recording unit 16a. In this case, in the frequency characteristic 72c, the vibration peak 80a that appears near the natural vibration frequency 78 of the table base 66, that is, 180 Hz, is attributed to the table base 66.

[0079] Then, in Figure 5 (B) shows the frequency characteristics of vibration obtained after repeatedly operating the cutting device 2 when a change occurs in some components. Figure 5 (B) is a diagram schematically showing the frequency characteristics of vibration when there is a change in the table base 66. Figure 5 The frequency characteristics 72d and Figure 5 As can be seen from the comparison with the frequency characteristic 72c shown in (A) of FIG. 7 , in the frequency characteristic 72d , the vibration peak 80b attributed to the table base 66 is shifted from the natural frequency 78 to the high vibration frequency side.

[0080] At this time, when the change of the worktable base 66 exceeds the allowable range and the difference 82b between the vibration frequency of the vibration peak 80b and the natural vibration frequency 78 of the worktable base 66 exceeds the specified range, the determination unit 16c determines that there is a change in the vibration peak 80b.

[0081] When the determination unit 16c makes a determination, a component other than the X-axis servo motor 60 may be used as a vibration source to generate vibration. For example, a θ-axis motor 66a that rotates the holding table 14 around an axis in a direction perpendicular to the holding surface 14a may be used as a vibration source. In this case, Figure 2 As shown, the reverse driving is repeated to generate vibration 68b at a vibration frequency within a predetermined range.

[0082] In addition, information related to the state of each component of the cutting device 2 when the vibration waveform is obtained can also be stored in the control unit 16. When observing the vibration, each component can be controlled by the control unit 16 based on the stored information. For example, the vibration waveform is changed according to the relative position of the worktable slider 64 relative to the X-axis ball screw 62. Therefore, when determining whether the components of the cutting device 2 have changed before and after the operation, in order to implement the vibration measurement under certain conditions, the relative position must be the same in each measurement.

[0083] Therefore, the relative position of the holding table slider 64 with respect to the X-axis ball screw 62 is stored in the control unit 16 as information related to the state of the X-axis ball screw 62 or the table base 66. And when determining whether there is such a change, the control unit 16 moves the holding table slider 64 to a predetermined position based on the information, generates vibrations through the vibration source, and obtains the vibration waveform through the vibration sensor 18.

[0084] In addition, when the determination unit 16c is used to perform the determination, the determination is performed during the period when the cutting (processing) of the cutting unit (processing unit) and the cleaning process of the workpiece 7 by the cleaning unit 50 are not performed. The vibration generated by resonance in each component tends to be weaker than the vibration generated by the cutting device 2 during the processing and cleaning of the workpiece 7. Therefore, when the determination unit 16c is intended to perform the determination during the processing and cleaning of the workpiece 7, the vibration generated by the resonance is sometimes buried in the vibration waveform generated by the processing and cleaning. In addition, when the vibration frequency of the vibration generated by the vibration source is scanned to calculate the frequency characteristics of the vibration, when the determination unit 16c is performed, the vibration source of the vibration is sometimes degraded and the predetermined vibration cannot be generated when the determination unit 16c performs the determination. For example, if the X-axis ball screw 62 is significantly degraded, even if the X-axis servo motor 60 is operated to generate vibrations of a predetermined vibration frequency, it is sometimes impossible to generate vibrations of the target vibration frequency.

[0085] Therefore, it is also possible to check in advance whether the vibration source is in a state of emitting vibrations of the target vibration frequency. For example, a vibration sensor capable of detecting the vibration frequency of the vibration can be installed on the worktable slider 64, and an instruction can be issued to make the vibration source generate vibrations of a specified vibration frequency to test whether the vibration of the specified vibration frequency is detected by the vibration sensor. In this case, it is also possible to determine whether there is a change in the X-axis servo motor 60 based on the relationship between the instruction and the detected vibration.

[0086] As described above, the processing device of the present embodiment has a self-diagnosis unit that realizes the self-diagnosis function. Therefore, even if there is no highly capable operator to check the processing device, it is possible to detect the occurrence of changes when the components change. Here, the self-diagnosis unit refers to a unit that has a vibration source, a vibration sensor, a natural vibration frequency recording unit, a frequency characteristic storage unit, and a determination unit, etc., and they cooperate to diagnose the state of the processing device. Therefore, according to the present embodiment, a processing device with a self-diagnosis function is provided.

[0087] In addition, the present invention is not limited to the description of the above-mentioned embodiment, and various modifications can be made and implemented. For example, in the above-mentioned embodiment, the case where the determination unit 16c of the self-diagnosis unit determines whether the components belonging to the X-axis moving mechanism 58 have changed is described, but one mode of the present invention is not limited to this. For example, the determination unit 16c can also determine whether the components belonging to the cleaning unit 50 have changed. Figure 3 (B) is a side view schematically showing generation of vibration in the washing unit 50 .

[0088] When determining whether there is a change in the components belonging to the cleaning unit 50, for example, the servo motor 70b that rotates the cleaning table 52 is used as a vibration source of the self-diagnosis unit. In this case, the servo motor 70b is operated while repeatedly reversing to generate vibration 68c. Thus, for example, it is possible to determine whether there is a change in the cleaning table 52 or the rotating shaft 70a.

[0089] In addition, the structure, method, etc. of the above-mentioned embodiment can be carried out with appropriate changes as long as it does not depart from the scope of the purpose of the present invention.

Claims

1. A processing device with a self-diagnosis function, the processing device having: A holding table that holds a workpiece; and a processing unit for processing the workpiece held by the holding table; It is characterized in that The processing device has: A control unit that controls various components of the processing device; and a self-diagnosis unit for diagnosing a state of the processing device when the processing unit is not processing; The self-diagnostic unit has: a vibration source that imparts vibrations of a frequency within a predetermined range to the processing device; and a vibration sensor that observes the vibration generated by the vibration source and propagates in the processing device to obtain a vibration waveform, The self-diagnosis unit also has in the control unit: a natural vibration frequency recording unit which, when the components of the processing device are in a normal state, calculates the frequency characteristics of the vibration based on the vibration waveform obtained by observing the vibration propagating in the processing device using the vibration sensor, and records the vibration frequency that resonates in the components of the processing device as the natural vibration frequency; a frequency characteristic storage unit that stores the frequency characteristic of the vibration calculated based on the vibration waveform acquired by the vibration sensor; and The determination unit determines that there is a change in the component to which the vibration peak belongs, when a difference between the vibration frequency of the vibration peak included in the frequency characteristics of the vibration and the natural vibration frequency recorded in the natural vibration frequency recording unit of the component to which the vibration peak belongs exceeds a prescribed range, The control unit stores information related to the state of each component of the processing device when the vibration waveform is acquired when the natural vibration frequency recording unit records the natural vibration frequency. The control unit controls each component of the processing device based on the information related to the state of each component of the processing device when the frequency characteristic storage unit stores the frequency characteristic after the operation of the processing device, and then generates vibration through the vibration source.

2. The processing device with self-diagnosis function according to claim 1, characterized in that: The vibration source is an actuator including a servo motor, and generates vibrations having a vibration frequency within the predetermined range by repeatedly performing reverse rotation of the servo motor.

3. The processing device with self-diagnosis function according to claim 2, characterized in that: The servo motor rotates the ball screw or the holding table, and the ball screw moves the holding table or the machining unit.

4. The processing device with self-diagnosis function according to any one of claims 1 to 3, characterized in that: The vibration sensor is an acceleration sensor.

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