Movable mechanism and method for diagnosing a movable mechanism

Abstract

To provide a movable mechanism which can easily determine abnormality due to occurrence of rust, adhesion of foreign matter, distortion and the like.SOLUTION: A movable mechanism comprises: a collation section that collates a rotation speed N of a stepping motor 81 and a pulse signal S generated by a pulse signal generating section 120; a synchronization determination section that determines whether or not the rotation speed N of the stepping motor 81 and the pulse signal S are out of synchronization; a first storage section and a second storage section that store pulse frequencies H1, H2 when becoming out of synchronization in the case that out of synchronization is determined by the synchronization determination section; and a time elapse determination section that compares the pulse frequency H1 stored in the first storage section and the pulse frequency H2 stored in the second storage section, and determines abnormality with elapse of time. The pulse frequency H1 when becoming out of synchronization in an initial stage is stored in the first storage section, the pulse frequency H2 when becoming out of synchronization in a stage of elapse of time is stored in the second storage section, and when abnormality is determined by the time elapse determination section, abnormalities such as rust, adhesion of foreign matter, distortion and the like are determined.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a movable mechanism and a method for diagnosing a movable mechanism.

Background Art

[0002] A wafer on which a plurality of devices such as ICs and LSIs are partitioned by a division line and formed on the surface is divided into individual device chips by a dicing device or a laser processing device, and is used in electric devices such as mobile phones and personal computers.

[0003] A dicing device generally includes a cassette table for placing a cassette containing a wafer supported by a frame, a carry-out means for carrying out the frame supporting the wafer from the cassette, a temporary receiving support portion for mechanically aligning the carried-out frame, a transfer means for transferring the frame supporting the wafer from the temporary receiving support portion to a chuck table, a processing feed means for feeding the chuck table, a cutting means for cutting the wafer held together with the frame on the chuck table, an indexing feed means for indexing the cutting means, a plunge feed means for plunge-feeding the cutting means, and a transfer means for transferring the frame supporting the cut wafer to a cleaning means, and can divide the wafer into individual device chips with high precision.

[0004] Further, a movable mechanism including the carry-out means, the temporary receiving support portion, the transfer means, the processing feed means, the indexing feed means, the plunge feed means, etc. includes a drive source, a ball screw that is connected to the drive source and rotates, a nut that is screwed onto the ball screw, a movable body that is supported by a guide rail and moves, and a control means for controlling the drive source.

[0005] And the drive source is appropriately adopted as needed a high-output servo motor or a stepping motor with relatively easy positioning control that does not require a scale and low output to enable high-precision control.

[0006] However, if abnormalities such as rust, foreign matter adhesion, or distortion occur in the ball screws, nuts, guide rails, etc. that constitute the above-mentioned movable mechanism, there is a problem in that high-precision control becomes difficult. Therefore, when such abnormalities occur in the movable mechanism, a load is placed on the drive source and an increase in torque (load current value) is observed, and the applicant has proposed a technique to diagnose the abnormality by detecting this torque (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2017-185579 [Overview of the project] [Problems that the invention aims to solve]

[0008] When a servo motor is used as the drive source for a movable mechanism, abnormalities can be easily detected by monitoring the torque (load current value) using the technology described above. However, when a stepping motor is used, it is driven by open-loop control, making it impossible to detect the load on the motor. As a result, even if abnormalities such as rust, foreign matter adhesion, or distortion occur in the ball screw, nut, and guide rail, causing problems with the operation of the movable function, it is difficult to easily diagnose the abnormality.

[0009] The present invention has been made in view of the above facts, and its main technical problem is to provide a movable mechanism and a method for diagnosing a movable mechanism, in which abnormalities caused by rust, foreign matter adhesion, distortion, etc., in the ball screws, nuts, guide rails, etc. that constitute the movable mechanism can be easily identified, even when a stepping motor is used as the drive source for the movable mechanism. [Means for solving the problem]

[0010] To solve the above-mentioned main technical problems, the present invention provides a movable mechanism comprising a stepping motor, a ball screw connected to and rotating with respect to the stepping motor, a nut screwed onto the ball screw, a movable body supported by a guide rail and movable, and a control means for controlling the stepping motor, wherein the control means includes a controller, a pulse signal generation unit that generates a pulse signal by the controller, and a driver that adjusts the current value based on the pulse signal from the pulse signal generation unit, and a comparison unit that compares the rotational speed of the stepping motor, which rotates according to the current value adjusted by the driver, with the pulse signal generated by the pulse signal generation unit, and the rotational speed of the stepping motor with the pulse signal generated by the pulse signal generation unit The system includes a synchronization determination unit that determines whether the components are synchronized or out of sync and have lost step, a first storage unit and a second storage unit that store a numerical value corresponding to the pulse frequency at the time of the loss of step when the synchronization determination unit determines that the components have lost step, and a time-elapsed determination unit that compares the numerical value corresponding to the pulse frequency stored in the first storage unit with the numerical value corresponding to the pulse frequency stored in the second storage unit to determine any abnormalities that occur over time. The first storage unit stores a numerical value corresponding to the pulse frequency when the components lose step at an initial stage, and the second storage unit stores a numerical value corresponding to the pulse frequency when the components lose step at a later stage of time. When the time-elapsed determination unit determines an abnormality, a movable mechanism is provided that can determine any abnormalities such as rust, foreign matter adhesion, or distortion in the ball screw, nut, and guide rail.

[0011] Furthermore, according to the present invention, a method for diagnosing a movable mechanism comprising a stepping motor, a ball screw connected to and rotating with respect to the stepping motor, a nut screwed onto the ball screw, a movable body supported and movable by a guide rail, and control means for controlling the stepping motor, wherein the control means includes a controller, a pulse signal generation unit that generates a pulse signal by the controller, and a driver that adjusts the current value by the pulse signal from the pulse signal generation unit, the method comprising: in an initial stage, a pulse frequency change step in which the controller changes the pulse frequency; a comparison step in which the rotational speed of the stepping motor, which rotates by the current value adjusted by the driver, and the pulse signal generated by the pulse signal generation unit are compared; and in the comparison step, a synchronization determination step in which it is determined that the rotational speed of the stepping motor and the pulse signal generated by the pulse signal generation unit are synchronized or not synchronized and are out of step. A method for diagnosing a movable mechanism is provided, comprising: a first storage step in which a numerical value corresponding to the pulse frequency at the time when a step out of step is determined is stored in a time determination step; a second storage step in which a pulse frequency change step, a comparison step, and a synchronization determination step are performed in the time progression stage, and in the synchronization determination step, a second storage step in which a numerical value corresponding to the pulse frequency at the time when a step out of step is determined is stored in a synchronization determination step is stored in a second storage step, and a time progression determination step in which a time progression abnormality is determined by comparing the numerical value corresponding to the pulse frequency stored in the first storage step with the numerical value corresponding to the pulse frequency stored in the second storage step, and if the numerical value corresponding to the pulse frequency stored in the second storage step is larger than an allowable value, a method for diagnosing a movable mechanism is provided, in which an abnormality such as rust, foreign matter adhesion, distortion is determined in the part including the ball screw, nut, and guide rail.

[0012] In the pulse frequency change step, it is preferable to change the pulse frequency from high to low. [Effects of the Invention]

[0013] The movable mechanism of the present invention comprises a stepping motor, a ball screw connected to and rotating with respect to the stepping motor, a nut screwed onto the ball screw, a movable body supported by a guide rail and movable, and control means for controlling the stepping motor, wherein the control means includes a controller, a pulse signal generation unit that generates a pulse signal by the controller, and a driver that adjusts the current value based on the pulse signal from the pulse signal generation unit, and includes a comparison unit that compares the rotational speed of the stepping motor, which rotates according to the current value adjusted by the driver, with the pulse signal generated by the pulse signal generation unit, a synchronization determination unit that determines whether the rotational speed of the stepping motor and the pulse signal generated by the pulse signal generation unit are synchronized or not synchronized and have lost step, and when the synchronization determination unit determines that it has lost step The device includes a first storage unit and a second storage unit that store numerical values ​​corresponding to the pulse frequency at the time of step loss, and a time-elapsed determination unit that compares the numerical value corresponding to the pulse frequency stored in the first storage unit and the numerical value corresponding to the pulse frequency stored in the second storage unit to determine abnormalities as time progresses. The first storage unit stores the numerical value corresponding to the pulse frequency when step loss occurs in the initial stage, and the second storage unit stores the numerical value corresponding to the pulse frequency when step loss occurs at a later stage of time. When an abnormality is determined by the time-elapsed determination unit, it determines abnormalities such as rust, foreign matter adhesion, and distortion in the parts including the ball screw, nut, and guide rail. Therefore, even when a stepping motor is used as a movable mechanism, it is possible to detect when a load is applied to the stepping motor, and the problem of not being able to detect the load current value and thus not being able to diagnose abnormalities is resolved.

[0014] Furthermore, the present invention's method for diagnosing a movable mechanism includes, in an initial stage, a pulse frequency change step in which the controller changes the pulse frequency; a comparison step in which the rotational speed of the stepping motor, which rotates according to the current value adjusted by the driver, and the pulse signal generated by the pulse signal generation unit are compared; a synchronization determination step in which, in the comparison step, it is determined that the rotational speed of the stepping motor and the pulse signal generated by the pulse signal generation unit are synchronized or not synchronized and have lost step; a first storage step in which, in the synchronization determination step, a numerical value corresponding to the pulse frequency at the time when it was determined that the step had lost step is stored; and in a time progression stage, the pulse frequency change step, the comparison step, and the synchronization determination step are performed, and in the synchronization determination step, a numerical value corresponding to the pulse frequency at the time when it was determined that the step had lost step is stored. The system includes a second storage step and a time-elapsed determination step which compares a numerical value corresponding to the pulse frequency stored in the first storage step with a numerical value corresponding to the pulse frequency stored in the second storage step to determine an abnormality over time. In the time-elapsed determination step, the numerical value corresponding to the pulse frequency stored in the first storage step is compared with the numerical value corresponding to the pulse frequency stored in the second storage step. If the numerical value corresponding to the pulse frequency stored in the second storage step exceeds an allowable value, an abnormality such as rust, foreign matter adhesion, or distortion is determined in the ball screw, nut, and guide rail. Therefore, even when a stepping motor is used as a movable mechanism, it is possible to detect that a load has been applied to the stepping motor, resolving the problem of not being able to detect the load current value and thus not being able to diagnose an abnormality. [Brief explanation of the drawing]

[0015] [Figure 1] This is an overall perspective view of the dicing apparatus. [Figure 2] This is the first flowchart. [Figure 3] This is the second flowchart. [Modes for carrying out the invention]

[0016] Hereinafter, embodiments relating to a movable mechanism constructed based on the present invention and a method for diagnosing the movable mechanism will be described in detail with reference to the attached drawings.

[0017] Figure 1 shows an overall perspective view of a dicing apparatus 1 equipped with a movable mechanism configured according to the present invention. The dicing apparatus 1 is mounted on a stationary base 2 and includes a holding means 3 for holding a workpiece, a cutting means 5 for performing cutting on the workpiece (not shown) held by the holding means 3, an X-axis feed means 6 for feeding the holding means 3 in the X-axis direction indicated by arrow X in the figure, a Y-axis feed means 7 for indexing and feeding the cutting means 5 in the Y-axis direction indicated by arrow Y in the figure, which is perpendicular to the X-axis direction, and a Z-axis feed means 8 for cutting and feeding the cutting means 5 in the Z-axis direction indicated by arrow Z in the figure, which is perpendicular to both the X-axis direction and the Y-axis direction.

[0018] On the upper surface 2c of the stationary base 2, a pair of first guide rails 2a, 2a aligned in the X-axis direction and a pair of second guide rails 2b, 2b aligned in the Y-axis direction are provided. The holding means 3 includes a first movable body 31 movably disposed on the first guide rails 2a, 2a, a cylindrical member 32 fixed to the upper surface 31a of the first movable body 31, a cover member 33 fixed to the upper part of the cylindrical member 32, a chuck table 34 protruding from the upper surface of the cover member 33 and holding the workpiece by suction, and a plurality (four in this embodiment) of clamps 35 arranged at equal intervals around the outer circumference of the chuck table 34 and gripping frames (not shown) that support the workpiece.

[0019] The X-axis feed means 6 includes a servo motor 61 and a ball screw 62. The servo motor 61 is disposed at one end of the ball screw 62, and the other end is rotatably supported by a bearing portion 63 disposed on the upper surface 2c of the base 2. The rotational movement of the servo motor 61 is transmitted by a ball screw mechanism constituted by a nut (not shown) disposed on the lower surface side of the first movable body 31 with which the ball screw 62 is screwed, and is converted into a linear movement. Thereby, the first movable body 31 can be advanced and retracted in the X-axis direction along the first guide rails 2a, 2a with which the sliding grooves 31b, 31b on the lower surface side of the first movable body 31 are slidably engaged.

[0020] The cutting means 5 is supported by the second movable body 53 and is disposed at a rear position adjacent to the region in the Y-axis direction where the holding means 3 moves in the X-axis direction. The cutting means 5 includes a spindle unit 50. A blade cover 52 is disposed on the tip side of the spindle unit 50 to protect the cutting blade 51 fixed to the tip of the rotating spindle rotatably supported by the spindle unit 50. A rotation drive source (not shown) is accommodated on the rear end side of the spindle unit 50, and the cutting blade 51 is rotated by driving the rotation drive source. Further, an imaging means 4 for imaging the workpiece held by the holding means 3 and detecting the region to be processed is integrally disposed on the spindle unit 50.

[0021] The second movable body 53 includes a horizontal wall portion 53a and a vertical wall portion 53b erected on the horizontal wall portion 53a. Rail engaging portions 53c, 53c disposed on the lower surface side of the horizontal wall portion 53a are slidably engaged with the second guide rails 2b, 2b and are configured to be movable by the Y-axis feed means 7. The Y-axis feed means 7 includes a servo motor 71 and a ball screw 72 whose end is rotatably supported by a bearing portion 73 disposed on the base 2. The rotational movement of the servo motor 71 is transmitted by a ball screw mechanism constituted by a nut (not shown) disposed on the lower surface side of the horizontal wall portion 53a screwed to the ball screw 72, and is converted into a linear movement, and the second movable body 53 is advanced and retracted in the Y-axis direction along the second guide rails 2b, 2b.

[0022] On the side surface of the vertical wall portion 53b of the second movable body 53, a pair of third guide rails 54, 54 supported along the Z-axis direction (vertical direction) indicated by the arrow Z are provided (a part is shown by a broken line). On the third guide rails 54, 54, a third movable body 55 that functions as a support member for supporting the spindle unit 50 is slidably attached, and it is configured to be movable in the vertical direction (Z-axis direction) by the Z-axis feed means 8. The Z-axis feed means 8 includes a stepping motor 81 and a ball screw 82 (shown by a broken line) whose end is supported by a bearing portion 83 (shown by a broken line) that is connected to the stepping motor 81 and rotates and is disposed below the side surface of the vertical wall portion 53b of the second movable body 53. The rotational movement of the stepping motor 81 is transmitted to a nut (not shown) disposed on the third movable body 55 that engages with the ball screw 82, thereby advancing and retreating the third movable body 55 along the third guide rails 54, 54 in the Z-axis direction. A rotation speed detection means (for example, a rotary encoder) is disposed on the stepping motor 81, and the actual rotation speed of the stepping motor 81 is output to a control means 100 described later.

[0023] A control means 100 is disposed in the dicing device 1. The control means 100 includes a controller 110 constituted by a computer, a pulse signal generation unit 120 that adjusts a pulse signal based on the calculation result by the controller 110, and a driver 130 that generates a current value for driving a stepping motor by the pulse signal from the pulse signal generation unit 120. The rotation speed of the stepping motor 81 is controlled by the pulse signal generated by the pulse signal generation unit 120. The rotation speed of the stepping motor 81 operating normally is synchronized with the pulse signal. The pulse signal generated by the pulse signal generation unit 120 has a period, and the rotation speed of the stepping motor 81 is proportional to the pulse frequency, and it becomes faster as the pulse frequency increases.

[0024] The controller 110 includes a central processing unit (CPU) that executes calculations according to a control program, a read-only memory (ROM) for storing the control program and the like, a read-write random access memory (RAM) for temporarily storing calculation results and the like, an input interface, and an output interface (details are not shown in the illustration). The control means 100 controls each operating part of the dicing device 1.

[0025] In the dicing apparatus 1 of this embodiment, the drive sources for the X-axis feed means 6 and the Y-axis feed means 7 are servo motors 61 and 71, respectively, and as described above, abnormalities can be detected by monitoring the torque (load current value) during driving. On the other hand, the stepping motor 81 of the Z-axis feed means 8 is driven by open-loop control using a driver 130 that adjusts the current value based on the pulse signal from the pulse signal generation unit 120 described above.

[0026] The movable mechanism of the present invention is realized by a Z-axis feed means 8 including the stepping motor 81 and a ball screw 82 connected to and rotating with the stepping motor 81, a third movable body 55 supported by third guide rails 54, 54 and movable in the vertical direction (Z-axis direction), a nut (not shown) disposed on the third movable body 55 and screwed onto the ball screw 82, and a control means 100 for controlling the stepping motor 81. The control means 100 configured to detect abnormalities in the movable mechanism of this embodiment includes the following configuration.

[0027] (Verification section) The matching unit compares the actual rotational speed N of the stepping motor 81, which rotates according to the current value adjusted by the driver 130, with the pulse signal S generated by the pulse signal generation unit 120. The actual rotational speed N of the stepping motor 81 is detected by, for example, a rotary encoder provided on the stepping motor 81, and the pulse signal S is the signal output by the pulse signal generation unit 120.

[0028] (Synchronization judgment unit) The synchronization determination unit determines whether the rotational speed of the stepping motor 81 and the pulse signal S generated by the pulse signal generation unit are synchronized or not synchronized and have lost step.

[0029] (First memory section) The first memory unit stores a numerical value corresponding to the pulse frequency at the time of the loss of synchronization when the synchronization determination unit determines that the device has lost synchronization. In particular, in this embodiment, it stores the pulse frequency H1 at the time when the device was determined to have lost synchronization in the synchronization determination step described later, which was performed in the initial stage. The initial stage in this embodiment refers to, for example, the stage when the dicing device 1 is in a new condition, or the stage when maintenance has been performed and the movable mechanism of this embodiment is in a condition similar to that of a new device. The numerical value corresponding to the pulse frequency may be the pulse frequency of the pulse signal S itself, or it may be the current value output by the driver 130 based on the pulse frequency. In the embodiment described below, the case in which the pulse frequency itself is used as the numerical value corresponding to the pulse frequency will be described.

[0030] (Second memory section) The second memory unit, like the first memory unit described above, is a memory unit that stores a numerical value corresponding to the pulse frequency at the time of loss of synchronization when the synchronization determination unit determines that the device is out of synchronization. In particular, in this embodiment, it stores the pulse frequency H2 at the time when the device is determined to be out of synchronization in the synchronization determination step described later, which is performed at a time-elapsed stage. The aforementioned time-elapsed stage includes, for example, the stage after a predetermined time has elapsed since cutting was performed by the dicing device 1 in a new or maintenance-completed state, the stage after the dicing device 1 has performed the desired cutting and then stopped, and then started up again to perform the next cutting.

[0031] (Time elapsed judgment unit) The time-elapsed judgment unit compares the pulse frequency H1 stored in the first memory unit with the pulse frequency H2 stored in the second memory unit to determine an abnormality associated with the passage of time. When an abnormality is determined by this time-elapsed judgment unit, it is determined that there is an abnormality in the ball screw 82, the nut, and the guide rails 54, 54 of the movable mechanism caused by rust, foreign matter adhesion, distortion, etc., and the system can display that an abnormality has been determined on an indicator means (not shown in the figure) or issue a warning with a buzzer or lamp.

[0032] The dicing apparatus 1 and the movable mechanism installed in the dicing apparatus 1 of this embodiment have generally the configuration described above, and the method for diagnosing the movable function of the dicing apparatus 1 will be described below.

[0033] Figure 2 shows a first flowchart F1 executed in the initial stage by the control means 100. The first flowchart F1 is performed in the initial stage, that is, when the dicing device 1 is new, or when the movable mechanism described above has been maintained and is in a state similar to that of a new device, and starts, for example, when power is turned on to the dicing device 1. In performing this first flowchart F1, first, a pulse frequency change step (S1) is performed. The pulse frequency change step (S1) is a step in which the pulse frequency of the pulse signal S used to control the rotation of the stepping motor 81 is changed in steps, preferably from a high to a low range of outputtable pulse frequencies. In this embodiment, for example, it is changed sequentially from a high to a low range of 100Hz to 10Hz. When the pulse signal generation unit 120 emits the first pulse signal S which has a predetermined high pulse frequency at the instruction of the controller 110, the pulse signal S is converted into a current value that drives the stepping motor 81 in the driver 130, and the stepping motor 81 is driven. The rotational speed of the stepping motor 81 is proportional to the pulse frequency of the pulse signal S. More specifically, the higher the pulse frequency (the higher the current value from the driver 130), the higher the rotational speed, and the lower the pulse frequency (the lower the current value from the driver 130), the lower the rotational speed.

[0034] Once the pulse frequency change step (S1) described above is started and the first pulse signal S is generated, the next matching step (S2) is performed. The matching step (S2) is a step of comparing the actual rotational speed N of the stepping motor 81, which is rotated by the current value adjusted by the driver 130, with the pulse signal S generated by the pulse signal generation unit 120.

[0035] If the matching step (S2) is performed, a synchronization determination step (S3) is performed to determine whether the rotational speed N of the stepping motor 81 and the pulse signal S generated by the pulse signal generation unit 120, which were matched in the matching step (S2), are synchronized or not synchronized and have lost steps. If the synchronization determination step (S3) determines that there is no loss of steps and they are synchronized (Yes), the process returns to the pulse frequency change step S1 described above, and the pulse frequency of the pulse signal S is changed (decreased) by a predetermined range. In this way, as long as no loss of steps occurs, the pulse frequency change step (S1), matching step (S2), and synchronization determination step (S3) are repeated, and the rotational speed of the stepping motor 81 is gradually reduced.

[0036] Incidentally, as mentioned above, the rotational speed N of the stepping motor 81 is basically synchronized with the pulse signal S generated by the pulse signal generation unit 120. When the pulse frequency is high and the rotational speed of the stepping motor 81 is high, the operation of the stepping motor 81 is stable and step loss is less likely to occur, while the lower the rotational speed of the stepping motor 81, the more likely step loss is to occur. Furthermore, even if the dicing device 1 is in a new condition or in a condition similar to new after maintenance has been completed, friction exists between the ball screw 82 and the nut (not shown), and friction between the third guide rails 54, 54 and the third movable body 55. Therefore, even if the dicing device 1 is in a new condition, the pulse signal and the rotational speed of the stepping motor 81 will not synchronize, i.e., step loss will occur, in the region of pulse frequency that is low enough not to be judged as a malfunction of the movable mechanism described above. If a step loss is determined (No) in the synchronization determination step (S3) of this first flowchart F1, the first storage step (S4) is performed to store the pulse frequency H1 at the time of the synchronization determination step (S3) in the first storage unit described above, and the first flowchart F1 is completed (END). However, the present invention is not limited to storing the pulse frequency H1 at the time of the synchronization determination step (S3) in the first storage unit, but may store other values ​​as long as they are numerical values ​​corresponding to the pulse frequency H1. For example, as described above, the current value for driving the stepping motor 81 in the driver 130 is determined based on the pulse frequency of the pulse signal S generated in the pulse signal generation unit 120, so the current value is a numerical value corresponding to the pulse frequency, and the current value at the time of the synchronization determination step (S3) in which a step loss was determined may be stored in the first storage unit.

[0037] Once the pulse frequency H1 is stored in the first memory unit according to the first flowchart F1 performed in the initial stage described above, the dicing device 1 performs cutting. This cutting is performed by suction-holding the workpiece (e.g., a semiconductor wafer) in the chuck table 34 of the holding means 3, and operating the cutting means 5, X-axis feed means 6, Y-axis feed means 7, Z-axis feed means 8, etc. (details are omitted). After repeated cutting of this type over time, it is necessary to periodically diagnose whether the movable mechanism using the stepping motor 81 has lost steps. Therefore, at predetermined time intervals, a diagnosis is performed based on the second flowchart F2 shown in Figure 3. The timing of this diagnosis can be arbitrarily set to occur at predetermined time intervals, for example, every day, every week, every time the power is turned on, etc.

[0038] The second flowchart F2 of this embodiment, shown in Figure 3, is described below assuming that it is performed each time the power is turned on again after the cutting process has been performed for a predetermined time and the dicing device 1 has been stopped.

[0039] In implementing this second flowchart F2, the pulse frequency change step (S10) is performed first. The pulse frequency change step (S10) is a step in which the pulse frequency of the pulse signal S used to control the rotation of the stepping motor 81 by operating the pulse signal generation unit 120 based on the instruction of the controller 110 is changed, and similar to the pulse frequency change step (S1) described above, the frequency is changed in steps from high to low within the range of 100Hz to 10Hz. When the controller 110 emits the first pulse signal S which has a predetermined high pulse frequency, the driver 130 converts it into a current value that drives the stepping motor 81, and the stepping motor 81 is driven.

[0040] Once the pulse frequency change step (S10) described above is started and the first pulse signal S is generated, the next matching step (S11) is performed. The matching step (S11) is a step in which the actual rotational speed N of the stepping motor 81, which rotates according to the current value adjusted by the driver 130, is compared with the pulse signal S generated by the pulse signal generation unit 120, similar to the matching step (S2) described above.

[0041] If the matching step (S11) is performed, a synchronization determination step (S12) is performed to determine whether the rotational speed N of the stepping motor 81, which was matched in the matching step (S11), and the pulse signal S generated by the pulse signal generation unit 120 are synchronized or not synchronized and have lost steps. In this synchronization determination step (S12), it is determined whether the current pulse signal S and the actual rotational speed N of the stepping motor 81 are synchronized or not. If it is determined that they are synchronized (Yes), the process returns to the pulse frequency change step (S10), and the pulse frequency of the pulse signal S is changed (decreased) by a predetermined range. In this way, the rotational speed of the stepping motor 81 is gradually reduced by repeating the pulse frequency change step (S10), the matching step (S11), and the synchronization determination step (S12) as long as no step loss occurs.

[0042] If the rotational speed of the stepping motor 81 is gradually reduced and it is determined (No) in the synchronization determination step (S12) of this flowchart F2 that a step loss has occurred, the next step is performed, and the pulse frequency H2 at the time the step loss was determined is stored in the second memory unit described above in the second memory unit described above in the second memory step (S13). If, after some time has passed since the cutting process was performed by the dicing device 1, rust, foreign matter, distortion, etc. occur in the parts including the ball screw 82, nuts (not shown), third guide rails 54, 54, etc. that constitute the movable mechanism, a step loss is likely to occur even at a high pulse frequency. Therefore, if the second memory step (S13) has been performed, the next step is performed, and the pulse frequency H1 stored in the first memory step (S4) of the first flowchart F1 described above and the pulse frequency H2 stored in the second memory step (S13) of flowchart F2 are compared, and a time-elapsed determination step (S14) is performed to determine whether the pulse frequency H2 is greater than the allowable value α, that is, whether there is a time-elapsed abnormality.

[0043] If it is determined that the pulse frequency H2 stored in the second memory unit is not greater than the pulse frequency H1 stored in the first memory step (S4) by an allowable value α (No), it is determined that the system is in a normal state, and the system proceeds to the next step (S15), outputs a normal signal, and terminates the second flowchart F2 (END). On the other hand, if it is determined that the pulse frequency H2 stored in the second memory unit is greater than the pulse frequency H1 stored in the first memory step (S4) by an allowable value α (Yes), it is determined that the movable mechanism is in an abnormal state, and the system proceeds to the next step (S16), outputs the abnormal signal to a display means (not shown) or the like, and terminates the flowchart F2 (END). The allowable value α described above is determined appropriately considering the operating precision required of the movable mechanism of the embodiment, and the effects of step loss caused by rust, foreign matter adhesion, distortion, etc. in the movable function.

[0044] In the embodiments described above, when a loss of synchronism is determined in the synchronization determination step (S3) in the first flowchart F1 and the synchronization determination step (S12) in the second flowchart F2, the pulse frequency H1 is stored in the first memory unit and the pulse frequency H2 is stored in the second memory unit. However, the present invention is not limited to this, and other values ​​corresponding to pulse frequencies H1 and H2 may be stored. As described above, the first memory unit can also store a current value corresponding to pulse frequency H1. If a current value corresponding to pulse frequency H1 is stored in the first memory unit in the first storage step (S4), then a current value corresponding to pulse frequency H2 is also stored in the second storage step (S13), and the time elapsed determination step (S14) is executed based on these two current values.

[0045] According to the movable mechanism and diagnostic method for the movable mechanism described above, even when a stepping motor is used as the movable mechanism, it is possible to detect when a load is applied to the stepping motor, thus resolving the problem of not being able to detect the load current value and therefore not being able to diagnose an abnormality.

[0046] The present invention is not limited to the embodiments described above. In the embodiments described above, the pulse frequency change steps (S1) and (S10) changed the pulse frequency of the pulse signal S generated by the pulse signal generation unit 120 from a high state to a low state. However, the present invention is not limited to this, and it is possible to similarly diagnose an abnormality by changing the pulse frequency from a low state to a high state. In that case, in the synchronization determination step, the pulse frequency at the time of the synchronization failure determination is stored in the first and second storage steps. The pulse frequency change steps (S1) and (S10) are performed until synchronization failure is no longer determined, and the pulse frequency at the time of the last synchronization failure determination is stored in the first and second storage units.

[0047] Furthermore, in the above-described embodiment, a stepping motor 81 was used as the drive source for the Z-axis feed means 8 of the dicing device 1 to configure the movable mechanism of this embodiment. However, the present invention is not limited to this, and the movable mechanism of the present invention may also be configured by using stepping motors as the drive sources for the X-axis feed means 6 and the Y-axis feed means 7. Moreover, as described above, the movable mechanism configured based on the present invention is not limited to being used in any part of the dicing device 1, but also includes cases where it is applied to other devices. [Explanation of symbols]

[0048] 1: Dicing device 2: Base 2a: First guide rail 2b: Second guide rail 3: Holding means 31: First movable body 34: Chuck Table 4: Imaging means 5:Cutting means 50: Spindle Unit 51: Cutting blade 53: Second movable body 54: Third guide rail 55: Third movable body 6: X-axis feed mechanism 61: Servo motor 62: Ball screw 7: Y-axis feed mechanism 71: Servo motor 72: Ball screw 8: Z-axis feed mechanism 81: Stepping motor 82: Ball screw 100: Control means 110: Controller 120: Pulse signal generation unit 130: Driver F1: First flowchart F2: Second flowchart

Claims

1. A movable mechanism comprising a stepping motor, a ball screw connected to and rotating with respect to the stepping motor, a nut screwed onto the ball screw, a movable body supported by a guide rail and movable, and control means for controlling the stepping motor, The control means includes a controller, a pulse signal generation unit that generates pulse signals using the controller, and a driver that adjusts the current value using the pulse signals from the pulse signal generation unit. A comparison unit that compares the rotational speed of the stepping motor, which rotates according to the current value adjusted by the driver, with the pulse signal generated by the pulse signal generation unit, A synchronization determination unit that determines whether the rotational speed of the stepping motor and the pulse signal generated by the pulse signal generation unit are synchronized or not synchronized and are out of step, When the synchronization determination unit determines that a step loss has occurred, it stores a first storage unit and a second storage unit that store a numerical value corresponding to the pulse frequency at the time of the step loss. The system includes a time-elapsed determination unit that compares a numerical value corresponding to a pulse frequency stored in the first storage unit with a numerical value corresponding to a pulse frequency stored in the second storage unit to determine an abnormality associated with the passage of time. A numerical value corresponding to the pulse frequency in the case of a step-out in the initial stage is stored in the first memory unit. The second memory unit stores a numerical value corresponding to the pulse frequency when a step-out occurs during the elapsed time. A movable mechanism that, when an abnormality is detected by the time-elapsed judgment unit, detects abnormalities such as rust, foreign matter adhesion, or distortion in the ball screw, nut, and guide rail.

2. A method for diagnosing a movable mechanism comprising a stepping motor, a ball screw connected to and rotating with respect to the stepping motor, a nut screwed onto the ball screw, a movable body supported by a guide rail and movable, and control means for controlling the stepping motor, wherein the control means includes a controller, a pulse signal generation unit that generates pulse signals using the controller, and a driver that adjusts the current value based on the pulse signals from the pulse signal generation unit, In the initial stages, A pulse frequency change step in which the pulse frequency is changed by the controller, A comparison step involves comparing the rotational speed of the stepping motor, which rotates according to the current value adjusted by the driver, with the pulse signal generated by the pulse signal generation unit. The matching step includes a synchronization determination step in which it is determined that the rotational speed of the stepping motor and the pulse signal generated by the pulse signal generation unit are synchronized or not synchronized and are out of step, The synchronization determination step includes a first storage step of storing a numerical value corresponding to the pulse frequency at the time of the synchronization determination, At the stage of time progression, The pulse frequency change step, the matching step, and the synchronization determination step are performed, and a second storage step is performed to store a numerical value corresponding to the pulse frequency at the time when a step loss was determined in the synchronization determination step. The system includes a time-elapsed determination step which compares a numerical value corresponding to the pulse frequency stored in the first storage step with a numerical value corresponding to the pulse frequency stored in the second storage step to determine an abnormality in the elapsed time, In the time elapsed determination step, A method for diagnosing a movable mechanism, which involves comparing a numerical value corresponding to a pulse frequency stored in the first storage step with a numerical value corresponding to a pulse frequency stored in the second storage step, and determining if the numerical value corresponding to the pulse frequency stored in the second storage step is larger than an allowable value, thereby determining an abnormality such as rust, foreign matter adhesion, or distortion in the ball screw, nut, or guide rail.

3. The method for diagnosing a movable mechanism according to claim 2, wherein the pulse frequency is changed from high to low in the pulse frequency change step.

Images