JP5819746B2 - Laser processing equipment - Google Patents

Description

  The present invention relates to a laser processing apparatus that deflects a laser beam output from a laser oscillator and irradiates a predetermined position to be processed to process the laser beam.

  In recent years, laser processing machines are required to prevent deterioration in processing accuracy due to aging and to maintain high productivity. The processing accuracy of the laser processing machine depends on the positioning accuracy of the mirror of the galvano scanner. If production is continued with the positioning accuracy of the mirror of the galvano scanner lowered, the possibility of processing failure increases. And when a processing defect occurs, there is a risk of causing a large economic loss. In addition, if a defective product is made, it is necessary to stop production and investigate the cause and take countermeasures. And it often takes a long time to elucidate the cause of processing defects.

  In Patent Document 1, a galvano scanner control method and a galvano scanner capable of positioning a mirror at a high speed regardless of a swing angle, and laser processing for piercing a printed board by irradiating a laser with such a galvano scanner. The machine is listed. In Patent Document 1, as described in FIG. 1 (FIG. 17 of the present specification), the actuator 110 that swings the mirror is operated based on the deviation between the command signal 215 and the current position 242. The gain change of the actuator 110 according to the angle is measured, and the operation amount of the actuator 110 is corrected so as to eliminate the gain change. As a result, it is possible to suppress the influence of fluctuations in the torque constant (gain change can be regarded as a change in the torque constant) according to the swing angle, so that the response characteristics are uniform over the entire scanning region. It is described that the positioning speed can be improved.

  Further, Patent Document 2 describes a galvano scanner control device having a mechanical characteristic diagnosis function that calls attention in advance before a poor accuracy occurs.

  Then, as described in FIG. 2 (FIG. 19 of the present specification) of Patent Document 2 as the configuration, an excitation signal generator 12 that generates an excitation signal for measuring the frequency characteristics of the galvano scanner, A frequency characteristic calculation unit 13 for calculating a frequency characteristic when the galvano scanner is operated by an excitation signal, machine state diagnosis data describing the characteristics of the frequency characteristic of the galvano scanner and the machine state of the galvano scanner, and frequency characteristic calculation A machine state diagnosis unit 15 for diagnosing whether the galvano scanner is in a normal state or an abnormal state based on the frequency characteristic calculated by the unit and the machine characteristic diagnosis data; and a display unit 16 for outputting a diagnosis result of the mechanical characteristic diagnosis unit; It has.

  Among these prior arts, the prior art will be described with reference to the description and the drawings of Patent Document 1 in particular. FIG. 12 is a block diagram showing a configuration of a galvano scanner servo mechanism in a conventional laser beam machine.

The electromagnetic swing actuator 110 of the galvano scanner 100 swings the swing shaft 111. A mirror 130 is attached to one end of the swing shaft 111 via a mirror mount 131, and an angle detector 120 is attached to the other end. With the configuration described above, the direction of the mirror 130 changes according to the swing of the swing shaft 111, and the laser beam 30 incident on the mirror 130.
The emission direction of the light is changed. The swing angle of the mirror 130 connected to the swing shaft 111 is detected by the angle detector 120. The host controller 10 instructs the galvano scanner controller 20 on the target positioning angle 11 of the mirror 130 in order to process a predetermined position with the laser beam 30 based on the NC program. A laser beam 30 output from a laser oscillator (not shown) is reflected by a mirror 130 and irradiated onto a processing position of an object through an Fθ lens 140. In the drawing, three machining positions of point A, point B, and point C corresponding to the three swing angles of the mirror 130 are shown.

  FIG. 13 is a block diagram of a scanner servomechanism constituting the conventional galvano scanner control device 20. The left side from the broken line is a portion executed by the software of the servo processor, and the right side is a hardware connection relation and signal. Shows the flow.

  The target trajectory generation processing unit 210 calculates the galvano scanner swing angle target value 215 each time based on the target positioning angle 11, and generates the target trajectory of the scanner servo mechanism. The target value 215 is a deviation 225 by subtracting the swing angle 255 of the scanner detected by the subtracting means 222. This deviation 225 is subjected to a control calculation process by the compensation element 220 to calculate an operation amount signal 226. The manipulated variable signal 226 is converted into an analog signal by the D / A converter 230 and becomes a command value (drive signal) 21 of the current control system 240. The armature of the galvano actuator 110 is connected to the output side of the current control system 240, and a current detection resistor 241 is connected in series with the armature. The terminal voltage of the current detection resistor 241 is detected by the differential amplifier 242 and fed back to the current control system 240 as a current signal. The encoder 120 coupled to the swing shaft 111 generates a pulse (position signal) 22 according to the swing amount, and this pulse is counted by a pulse counter 250 and fed back as a swing angle 255.

  By repeating these processes, the mirror 130 gradually approaches the target position. When the positioning is completed, a positioning completion signal 12 is sent from the galvano scanner control device 20 to the host control device 10.

  FIG. 14 is a cross-sectional view of the galvano actuator of Patent Document 1. A cylindrical inner yoke 112 is disposed so as to surround the swing shaft 111, and permanent magnets 113a, 113b, 113c, and 113d that are divided into four in the circumferential direction are disposed outside the cylindrical inner yoke 112 with a cylindrical gap G therebetween. ing. The permanent magnets 113a to 113d are magnetized so as to be polarized in the radial direction, and the permanent magnet 113a and the permanent magnet 113c, and the permanent magnet 113b and the permanent magnet 113d are magnetized in the same direction. An outer yoke 114 is disposed outside the permanent magnets 113a to 113d, and these form a magnetic circuit. The magnetic flux M in the substantially radial direction is generated in the gap G by the magnetic field formed by the permanent magnets 113 a to 113 d and the inner yoke 112. In the gap G, the wire groups 115a, 115b, 115c, and 115d constituting the armature coil are arranged as shown in the figure.

With the above configuration, when the coil is energized, current flows through the wire groups 115a, 115b, 115c, and 115d in the direction shown in the figure, and the wire groups 115a to 115d run in the circumferential direction due to the interaction between magnetic flux and current. Force (Lorentz force) acts. Coil, that is, strand group 115a ~
Since 115 d is fixed to the swing shaft 111, this force becomes a torque for driving the swing shaft 111. This torque is proportional to the current flowing through the coil, and its proportionality constant is the gain.

  Here, the galvano scanner performs an operation of swinging the mirror within a limited angular range, but the characteristics of the galvano scanner within this angular range are not necessarily uniform. That is, in the case of the galvano actuator 110 shown in FIG. 7, the magnetic flux M near the center of the permanent magnets 113a to 113d is directed in the radial direction, but as it approaches the end, it is inclined with respect to the radial direction and the density decreases. For this reason, when the strand group 115a-115d approaches the edge part of permanent magnet 113a-113d, the fall of a gain will arise.

  FIG. 15 is a graph showing the relationship between the swing angle and the gain in Patent Document 1. The swing angle θB is the center of swing, the swing angle θA is the plus side, and the swing angle θC is the minus side angle. 5 is a swing angle corresponding to the processing positions A, B, and C in FIG.

  FIG. 16 is a diagram in which graphs of deviation signals of the servo mechanism at the machining positions A, B, and C where the swing angles are θA, θB, and θC in Patent Document 1 are superimposed.

  As is clear from the figure, an appropriate response is shown at position B, but overshoot occurs at positions A and C. That is, since the gain varies depending on the swing angle, a servo mechanism having a good positioning response at one angle may cause overshoot or overdamping at another angle.

  However, it is difficult to make the intensity of the magnetic field acting on the coil uniform regardless of the swing angle, and the magnitude of the torque acting on the rotor varies depending on the swing angle even if the same current is passed. . Similarly, even in a galvano scanner that generates torque by another structure, it is difficult to prevent the gain from changing at all depending on the swing angle.

  Therefore, in Patent Document 1, a galvano scanner control method and a galvano scanner capable of positioning a mirror at a high speed regardless of a swing angle, and a printed circuit board by irradiating a user with such a galvano scanner. It aims at providing the laser processing machine which drills.

  As a means for this, in the galvano scanner which operates an actuator that swings the mirror based on the deviation between the command signal and the current position and controls the emission angle of the light incident on the mirror, A means for measuring the gain change of the actuator is provided, and the gain change of the actuator is measured by this means prior to the actual operation and the result is stored, and the operation of the actuator is performed so as to eliminate the gain change during the actual operation. It is characterized by correcting the amount.

  FIG. 17 is a block diagram of the scanner servomechanism constituting the galvano scanner control device 50 having the gain measurement function described in Patent Document 1. The left side from the broken line shows the part executed by the software of the servo processor. Shows the hardware connection and signal flow. In addition, the thing of the function equivalent to FIG. 13 attaches | subjects the same code | symbol, and abbreviate | omits the overlapping description.

  The excitation signal generation processing unit 260 generates a small amplitude sine wave signal. The frequency of this sine wave avoids the resonance frequency of the scanner actuator to be controlled, the frequency of various noises of the amplifier, the frequency region where the influence of friction is significantly low, etc., and the transfer function is a double integral as an inertial body. It is set to a frequency that indicates the characteristics.

  The signal connection cutoff processing unit 261 connects or blocks the signal output from the excitation signal generation processing unit 260 to the addition processing unit 262. The addition processing unit 262 adds the target value 215 output from the excitation signal generation processing unit 260 and the target value generation processing unit 210 and outputs the result to the subtraction unit 222.

  The output of the compensation element 220 is input to the terminal a of the signal connection switching processing unit 227 and the gain fluctuation compensation unit 300, and the output of the gain fluctuation compensation unit 300 is input to the terminal b of the signal connection switching processing unit 227. The output of the signal connection switching processing unit 227 is input to the D / A converter 230 from the terminal c.

  A swing angle 255 is input to the gain measurement signal processing unit 270 via the signal connection cutoff processing unit 271, and an operation amount signal 226 is input via the signal connection cutoff processing unit 272. The processing result 284 is stored in the memory. Stored at the specified address in 290.

  Next, the gain measurement signal processing unit 270 will be described. FIG. 18 is a block diagram illustrating a configuration of a gain measurement signal processing unit according to Patent Document 1. The input side of the first digital filter 273 is connected to the signal connection cutoff processing unit 271, and the output signal is input to the division processing unit 279 via the first peak hold 277. The input side of the second digital filter 274 is connected to the signal connection cutoff processing unit 272, and the output signal is input to the division processing unit 279 via the second peak hold 278. The first and second digital filters 273 and 274 have a band-pass characteristic that allows the same frequency component as the frequency of the sine wave generated by the excitation signal generation processing unit 260 to pass and blocks the other components. . Note that reference numeral 283 in FIG. 18 denotes a timing signal.

  Next, the operation of Patent Document 1 will be described. As described above, the gain changes according to the swing angle. Therefore, in order to suppress the response waveform fluctuation, it is necessary to measure the gain fluctuation shown in FIG. 15 according to each scanner and its setting.

  Therefore, prior to positioning, the gain corresponding to the swing angle is measured by the following procedure. First, the signal connection cutoff processing units 261, 271, and 272 are set to the connection side, the terminal c of the signal connection switching processing unit 227 is connected to the terminal a, and the output signal of the compensation element 220 is directly input to the D / A converter 230. To be entered. In this state, the target value generation processing unit 210 sets the target value 215 corresponding to the swing angle to be measured, and the excitation signal generation processing unit 260 generates a small amplitude sine wave signal. Since the sine wave signal output from the excitation signal generation processing unit 260 is added to the target value 215 by the addition processing unit 262, the oscillating shaft 111 is driven in a sine wave shape around the oscillation angle to be measured.

  The swing angle 255 and the manipulated variable signal 226 are taken in every sample period and processed by the first and second digital filters 273 and 274, respectively. The first and second digital filters 273 and 274 have a band-pass characteristic that allows the same frequency component as the frequency of the sine wave generated by the excitation signal generation processing unit 260 to pass and blocks the other components. Therefore, when a certain amount of time elapses after the start of vibration, an input signal component 275 to be controlled corresponding to the vibration signal and an output signal component 276 to be controlled corresponding to the vibration signal appear in the outputs of these filters. Since the first and second digital filters 273 and 274 perform the same processing, the influence of the filter is canceled when the transfer characteristics between the input signal component 275 and the output signal component 276 are examined.

  The input signal component 275 and the output signal component 276 are input to the first and second peak hold processing units 277 and 278, respectively, and the peak value of the sinusoidal signal is held, and the input signal amplitude 281 and the output signal amplitude are output as outputs. 282 is obtained.

  After a sufficient time has elapsed, the division processing unit 279 performs division processing using the timing signal 283, divides the input signal amplitude 281 by the output signal amplitude 282, and calculates the inverse number 284 of the control target gain. Is stored at the address specified by the address 291 corresponding to the swing angle at the time of measurement.

  The series of processing described above with reference to FIGS. 17 and 18 is repeated while changing the target value of the swing angle little by little within the movable range, thereby measuring the gain change with respect to the entire movable range. Remembered.

  At the time of processing, the signal connection cutoff processing units 261, 271, and 272 are set to the cutoff side, the terminal c of the signal connection switching processing 227 is connected to the terminal b, and the output signal of the compensation element unit 220 passes through the gain fluctuation compensation unit 300. To be input to the D / A converter 230. Then, the gain fluctuation compensator 300 refers to the memory 290 in accordance with the rocking angle 255, that is, the rocking angle θ, so as to cancel the gain change (for example, to be equal to the maximum gain value obtained by the measurement). A) The manipulated variable signal 226 is amplified and output to the D / A converter 230. As a result, since the gain is constant regardless of the swing angle θ, the mirror can be positioned at a high speed and the processing speed can be improved.

  Next, Patent Document 2 will be described in detail. 2 and 4 of Patent Document 2 are shown in FIGS. 19 and 20 of the specification of the present application.

  As shown in FIG. 19, an excitation signal generator 12 that generates an excitation signal for measuring the frequency characteristic of the galvano scanner, and a frequency characteristic when the galvano scanner is operated by the excitation signal are calculated. Based on the frequency characteristic calculator 13, the machine state diagnosis data describing the characteristics of the frequency characteristic of the galvano scanner and the machine state of the galvano scanner, and the frequency characteristic and mechanical characteristic diagnosis data calculated by the frequency characteristic calculator A machine state diagnosis unit 15 that diagnoses whether the scanner is in a normal state or an abnormal state, and a display unit 16 that outputs a diagnosis result of the machine characteristic diagnosis unit are provided. FIG. 20 is a diagram showing a change in frequency characteristics when the torsional rigidity between the mirror and the shaft of the galvano scanner is lowered. Since the first resonance frequency Fk1 is lowered, the mechanical state diagnosis result of the mirror abnormality is shown. ing.

JP 2005-234215 A JP 2009-192837 A

  However, Patent Document 1 does not have a function for diagnosing aging degradation of an actuator of a galvano scanner, in other words, there is no function for diagnosing whether the processing accuracy of a galvano scanner has deteriorated. Further, even when the machining accuracy deteriorates, there is no function for estimating the factor. Furthermore, there is no display function to show the countermeasures. Therefore, there is no preventive maintenance function for preventing the machining error before it occurs, and the occurrence of the machining error cannot be prevented in advance.

  Further, since Patent Document 2 focuses only on the mechanical characteristics (resonance frequency and gain) of the galvano scanner, if a failure or deterioration occurs that does not affect the resonance frequency, the deterioration and those It is not possible to diagnose the cause of this. Further, the galvano scanner rotates the mirror at a predetermined angle and moves and processes the laser beam. However, in Patent Document 2, the machine at which position (rotation angle) the mirror is only described at a single angle. It is not described whether the characteristics should be measured. Furthermore, there is no description about the influence of the rotational position of the mirror. There is no suggestion about the influence of the rotation angle of the mirror on the mechanical characteristics.

  In contrast to these conventional techniques, the present application diagnoses a change in the characteristics of the scanner with respect to the rotation angle of the mirror using a change in gain over time (for example, a change from the time of shipment to the time of diagnosis). Specifically, the gain is measured using the rotation angle as a parameter, and the deterioration of the scanner is diagnosed by comparing it with a diagnostic database prepared in advance based on the degree and characteristics of the change over time. In addition, by providing a function to display the cause (factor) and countermeasures for the presence or absence (normal or not) of the mirror positioning accuracy of the galvano scanner leading to processing defects, Prevent the generation of defective products. By displaying the positioning accuracy (machining accuracy) deterioration diagnosis function, estimation factors, and countermeasures, it is intended to facilitate maintenance, shorten maintenance time, and prevent productivity reduction.

In order to solve the above-described problem, a measuring unit that measures a gain change of the actuator according to a swing angle, a storage unit that stores a gain change measured by the measuring unit prior to an actual operation, and an actual operation The correction means for correcting the operation amount of the actuator so as to eliminate the gain change stored in the storage means, and comparing a plurality of predetermined patterns with the measurement result of the actuator after a predetermined time has passed. It is characterized by determining a pattern close to the measurement result from a plurality of types of patterns, and from the determined pattern , diagnosing processing accuracy degradation of the galvano scanner, and displaying the factor estimation and countermeasures. To do.

  In addition to the characteristics of gain change over time, it also has a function of diagnosing the deterioration of processing accuracy of the galvano scanner and displaying its factor estimation and countermeasures with reference to the magnitude of variation in position deviation. It is characterized by.

  With this configuration, it is possible to widely diagnose the degree and factor of the scanner positioning performance deterioration over the entire mirror rotation angle. In other words, it is possible to diagnose machining accuracy deterioration within the mirror movable range. As a result, the range of preventive maintenance of the apparatus can be expanded, the degree of positioning performance deterioration (decrease in machining accuracy) and its factor can be inferred, and the apparatus can be prevented from lowering in machining accuracy.

  Further, if the gain of the galvano scanner changes due to changes over time from shipment, the positioning accuracy may be deteriorated as a result. For this reason, by monitoring changes in gain from the time of shipment and collating them with the “gain change pattern and its fluctuation factors” created and installed in advance as a database, the change pattern and amount of change can be determined. From the size, it is possible to know whether or not the positioning accuracy of the galvano scanner has deteriorated and its cause.

  Therefore, by providing the galvano scanner with a gain diagnosis function, it is possible to display the diagnosis of the presence or absence of the mirror positioning accuracy of the galvano scanner and the cause and countermeasure. Thus, it is possible to prevent a decrease in positioning accuracy (processing accuracy) of the galvano scanner and to prevent generation of defective products.

FIG. 6 is a cross-sectional view of the galvano scanner 100. The galvano scanner 100 includes an electromagnetic oscillation actuator 110 and an angle detector 120. The electromagnetic oscillating actuator 110 has a magnetic circuit including a permanent magnet 113, a coil 115, and an outer yoke 114. The permanent magnet 113 is fixed in the axial direction by a stopper ring 116 and bonded to the swing shaft 111.
The swing shaft is held by two bearings 112. A Lorentz force, which is a force generated by a magnet and a coil to which a current is applied, is applied to the swing shaft 111, and the swing shaft 111 rotates. The angle detector 120 includes an angle detection unit 121 and a scale disk 122 attached to the swing shaft 111. A mirror 130 is fixed to the other end of the swing shaft 111 via a mirror mount 131. As described above, the galvano scanner 100 includes mechanical parts such as the permanent magnet 113, the bearing 112, the angle detector (encoder) 120, and the mirror 130. For this reason, the gain is affected by changes in the properties of these materials and machine elements.

  For this purpose, the torque diagnosis table (gain change pattern (features) and factors that reduce the positioning accuracy) prepared in advance is compared with the gain change at the time of diagnosis (age) to reduce the positioning accuracy. The degree and its factor can be estimated. At the same time, it is possible to display a countermeasure against a decrease in positioning accuracy.

The block diagram of the scanner servo mechanism which comprises the galvano scanner control apparatus provided with the gain diagnostic function. Gain diagnosis function explanatory drawing. Gain diagnostic table. The flowchart (method A) of a gain diagnostic procedure. Flow chart of gain diagnosis procedure (Method B). Flow chart of procedure for gain diagnosis (Method C). The block diagram which shows the structure of a gain measurement signal process part. Cross section of galvano scanner The block diagram which shows the structure of a galvanometer mirror servo mechanism. Explanatory drawing of the gain diagnostic function of 2nd Example. The gain diagnosis procedure of the second embodiment. The galvano scanner control device of the third embodiment (with a position deviation signal diagnosis function). Position deviation signal diagnosis function of the third embodiment. The block diagram which shows the structure of the conventional galvanometer mirror servomechanism. The block diagram of the scanner servo mechanism which comprises the conventional galvano scanner control apparatus. Sectional drawing of the conventional galvano actuator (patent document 1). The relationship between the swing angle and gain of a conventional galvano actuator (Patent Document 1). It is the figure which piled up the graph of the deviation signal of a servo mechanism when positioning of the same stroke is performed in the processing position whose rocking angles are θA, θB, and θC. The block diagram of the scanner servo mechanism which comprises the galvano scanner control apparatus provided with the conventional gain measurement function (patent document 1). The block diagram which shows the structure of the conventional gain measurement signal processing part (patent document 1). It is a block diagram of the conventional laser processing machine for printed circuit board drilling (patent document 2). The figure which shows the change of the frequency characteristic when the rigidity of the twist direction between the mirror of a conventional galvano scanner and a shaft falls.

  Hereinafter, a first embodiment for carrying out the present invention will be described with reference to the drawings.

  In the present embodiment, a galvano scanner control device having a gain diagnosis function will be described with reference to FIGS. FIG. 7 is a block diagram showing the configuration of the galvanometer mirror servo mechanism of this embodiment. In addition, the thing of an equivalent function is attached | subjected the same code | symbol as FIG. 12, and the overlapping description is abbreviate | omitted. Here, reference numeral 500 denotes a galvano scanner control device having a gain diagnosis function. The gain diagnosis function will be described later, but the gain change pattern obtained by comparing the gain at the time of product shipment and the gain at the time of diagnosis was created and installed in advance as a database. And the variation factor thereof, the presence / absence of a decrease in positioning accuracy and the factor estimation are performed, and the countermeasures are displayed. In addition to the conventional functions, the host controller 1000 instructs whether or not to execute the gain diagnosis function and the execution timing (time). Further, the host control apparatus 1000 uses the position deviation signal for the diagnosis of the galvano scanner together with the gain diagnosis function as shown in the second embodiment when performing only the gain diagnosis function as in the first embodiment. If necessary, the function is switched. Note that the presence or absence (timing) of the execution of the diagnostic function of the present invention may be performed at the timing when the galvano scanner control device updates the gain (that is, at the time of gain measurement before processing).

  FIG. 6 is an explanatory diagram of a cross-sectional view of the galvano scanner 100 of the present embodiment. Since this structure has been described above, the difference between the conventional galvano scanner of FIG. 14 and the present embodiment of FIG. 6 will be described. The conventional example of FIG. 14 is a so-called moving coil type galvano scanner in which the coil 115 rotates, but this embodiment is a so-called moving magnet type scanner in which the magnet 113 rotates. As described above, since this scanner is composed of mechanical parts such as the permanent magnet 113, the bearing 112, the angle detector (encoder) 120, and the mirror 130, the gain affects the influence of these magnets and machine elements. receive.

For this purpose, the "torque diagnosis table (gain change pattern and its variation factor), which has been measured and created in advance, and the amount of gain change at the time of diagnosis are collated. It is possible to estimate the degree of positioning accuracy and its factor, and to display the countermeasures at the same time, and it goes without saying that the present invention can also be applied to the conventional galvano scanner of FIG.

  FIG. 1 is a block diagram of a scanner servomechanism constituting a galvano scanner control device having a gain diagnosis function. In addition, the thing of an equivalent function is attached | subjected the same code | symbol as FIG. 17, and the overlapping description is abbreviate | omitted.

  The difference from the conventional galvano scanner control device (FIG. 17) is as follows. In the conventional galvano scanner device, before the positioning, the gain in the movable range (oscillation angle θ) is measured by the gain measurement signal processing, and then the correction coefficient 284 is calculated so that the gain does not fluctuate within the movable range. And stored in the memory 290. Then, at the time of processing, the gain variation compensation 300 amplifies the operation amount 226 so as to cancel the gain change with reference to the memory 290 according to the swing angle. As a result, the gain is constant regardless of the swing angle θ, so that the mirror can be positioned at a high speed and the processing speed can be improved.

  On the other hand, in the present invention, in order to prevent deterioration of the processing accuracy of the galvano scanner and to display the deterioration diagnosis of the galvano scanner and its estimation factor, and countermeasures, in the conventional control device, Gain diagnosis function is provided.

  The gain diagnosis function is a gain change pattern that has been created and installed in advance as a database for the magnitude and pattern of gain change obtained by comparing aging, for example, gain at product shipment and gain at diagnosis. By checking, the presence / absence of a decrease in positioning accuracy and the cause estimation are performed, and the countermeasure is displayed. In order to perform the gain diagnosis, a gain diagnosis unit 400, a diagnosis database 410, and a display unit 420 that displays the gain diagnosis result are provided.

  The diagnosis function of the gain diagnosis unit 400 will be described with reference to FIG. Since the gain with respect to the swing angle is automatically measured by the same configuration and procedure as those of the conventional galvano scanner control device, description thereof is omitted here.

  In the gain diagnosis unit 400, the gain 401 at the time of product shipment stored in the memory 290 is newly compared with the gain 284 measured by the gain measurement signal processing 270 at the time of diagnosis, and the change pattern of the gain is obtained. As compared with the “gain change pattern of torque diagnosis table (FIG. 3)” 402 recorded in the diagnosis database 410, the gain change pattern is any of the patterns (1) to (5) of the gain diagnosis table. The display unit 420 displays the presence / absence of a decrease in positioning accuracy, estimation of the cause thereof, and countermeasures thereof.

In FIG. 2, the gain at the time of shipment (solid line) and the gain at the time of diagnosis (dotted line) are almost the same. For this reason, the gain variation pattern corresponds to “(1) normal” of the gain change pattern in the torque diagnostic table FIG. 3 of the diagnostic database 410, and therefore, the diagnostic result 403 displays “normal” on the display unit 420. .

  Next, the torque diagnosis table recorded in the diagnosis database 410 will be described in detail with reference to FIG. The torque diagnosis table classifies gain changes, characteristics, diagnosis results, and countermeasures into five typical gain changes. The typical five are as follows. It is determined (selected) which pattern can be classified from the pattern of gain fluctuation at the time of shipment and at the time of diagnosis.

(Pattern 1) Normal type: The gain at the time of shipment is the same as that at the time of diagnosis (variation is a predetermined value or less).
(Pattern 2) Decreasing type over the entire movable range: The gain during diagnosis is smaller than that at the time of shipment over the entire movable range.
(Pattern 3) The position of the maximum value is moving type: The position of the maximum gain value is shifted between the time of shipment and the time of diagnosis.
(Pattern 4) Variation type only near the center: The gain at the time of diagnosis varies only near the rotation center.
(Pattern 5) Extremely large at the center, left and right: Gain at the time of diagnosis has peaks at the center and left and right.

  Here, the comparison of gain at the time of shipment and diagnosis is as follows. Both may compare the measured data directly. As in Patent Document 1, the gain at the time of shipment may be compared with the measurement result at the time of diagnosis by creating a fourth-order approximate expression from the measurement result. B. The method of A. Compared to the above, the calculation memory is small, and the diagnostic speed can be increased.

  The diagnosis result (presumed cause) and countermeasures are as shown in FIG. Specifically, in the case of (1), the diagnosis result is normal and no countermeasure is required. In the case of (2), the diagnosis result is thermal gain demagnetization and gain reduction or all-around bearing damage, and countermeasures are gain update, response speed setting change, bearing replacement, and galvano scanner replacement. In the case of (3), the diagnosis result is the deviation of the mechanical center between the encoder and the mirror, the deterioration of the mirror flatness due to the abnormal operation of the scanner, etc. The countermeasures are the gain update, the centering of the encoder and mirror, and the mirror replacement is there. In the case of (4), the countermeasure against the fretting wear of the bearing in the fine drive at the center is the execution of periodic maintenance operation for preventing the gain update and fretting wear, and if the improvement is not improved, the bearing is replaced. Periodic maintenance operations include rotating the scanner at the left and right maximum angles. In the case of (5), the diagnosis result is a Brunel dent in the bearing or fretting wear due to a drop during handling of the scanner, and the countermeasure is a gain update or a bearing replacement. The selected diagnosis result and countermeasure are displayed on the display unit.

  As described above, it is possible to display the presence / absence of a decrease in positioning accuracy, its cause, and countermeasures from the pattern of gain change with time.

  Next, a gain diagnosis procedure will be described with reference to FIGS. 4A to 4C. The gain measurement at the time of product shipment (initial value) and at the time of diagnosis (age) is performed according to the same procedure as in Patent Document 1. That is, the gain measurement signal processing is performed according to the procedure described in FIGS. For this reason, detailed description of the operation of each part is omitted here. The same operation (function) is given the same number.

  First, in step S101, the galvano scanner control device is activated in the gain measurement mode, and then in step S102, gain measurement with respect to the rotation angle is performed. Thereby, the gain at the time of diagnosis (latest) is known. Next, the gain of the previous (shipment) measurement and the gain of the current measurement (during diagnosis) stored in the memory in step S103 are transmitted to the gain diagnosis unit. Is sent to the gain diagnosis unit 400. Here, the memory 290 stores the previously measured gain. Since the current gain measurement result is overwritten in the memory, the previous gain measurement result is taken out before the current gain is measured and overwritten, and then the current gain measurement result is taken out and compared in step S104. You can know the change in gain. Of course, if there is room in the memory, the previous result and the current gain may be stored in the memory 290 separately.

  As described above, the variation pattern can be known from the previous gain measurement result and the current gain measurement result. It is also possible to record the normal gain at the time of shipment in the memory 290 and compare the gain at the time of shipment and the time of diagnosis (age point).

  Here, it is assumed that the previous gain measurement is a gain measurement at the time of shipment. However, it goes without saying that the time interval between the previous measurement and the current measurement can be set freely. Specifically, the gain change measurement interval can be freely set before and after the product processing, the periodic inspection period, or the user's needs.

  Next, in FIG. 4A (Method A), each pattern of gain fluctuation is compared with the measurement result measured by the gain diagnosis unit in Step S105, and the closest one of the five patterns in the torque diagnosis table is determined. Further, when the gain change pattern is composed of a plurality of patterns, all of them may be displayed. Then, the diagnosis result and countermeasure are transmitted to the display unit from the gain fluctuation pattern determined in step S106. Finally, in step S107, the diagnosis result and the countermeasure are displayed on the display unit. It is also possible to create a fourth-order approximation expression from the gain measurement result, and then determine which pattern of each pattern of gain change is applicable.

  Here, another embodiment of the comparison between the pattern and the measurement result performed in step S105 of FIG. 4a will be described. FIG. 4B (method B) performs processing by dividing step S105 of FIG. 4A into five determination steps. In step S115, it is determined whether or not this is the case with pattern 1 (normal). Thereafter, in step S116, pattern 2 (decreases in the entire movable range), in step S117, pattern 3 (the position of the maximum value moves), step S118. Is determined to apply to pattern 4 (changes only near the center), and in step S119, it is determined whether it applies to pattern 5 (maximum at the center and left and right). The diagnosis result and countermeasure are displayed by the fluctuation pattern. If none of the patterns is applicable, a message requiring investigation is displayed on the display unit in step S122. In this embodiment, the pattern performed earlier has a higher priority, and once the determination is passed, the pattern is immediately determined to be the pattern. In the embodiment in FIG. 4b, the processing is performed in the order of the patterns 1 to 5, but this order can be rearranged to the order of the patterns having higher priority.

  FIG. 4c (method C) is an embodiment in which the pattern determination in step S105 of FIG. 4a is processed in parallel. In this embodiment, after step S134 is completed, it is determined at step S135 whether the pattern 1 to pattern 5 are applicable. Thereafter, diagnosis results and countermeasures are transmitted from the matched pattern in step S136 to the display unit, and the diagnosis results and countermeasures are displayed on the display unit in step S137. In this embodiment, for example, the measurement result is determined to be a shape in which a plurality of shapes are combined, for example, a shape in which pattern 2 (decreasing in the entire movable range) and pattern 4 (changes only near the center) are combined. In this case, it is possible to determine that both the pattern 2 and the pattern 4 match, and display both diagnosis results and countermeasures on the display unit.

  In addition to the diagnosis results and countermeasures, the gain change pattern can be displayed for the display items of the first embodiment.

  The series of operations shown in FIGS. 4a and 4b may be performed before positioning as in Patent Document 1, or may be performed freely according to a periodic inspection period or the needs of the user. Is possible. Further, when the processing accuracy deteriorates, it may be used as a factor investigation.

  FIG. 5 is a block diagram showing the configuration of the gain measurement signal processing unit. This is basically the same as the block diagram showing the configuration of the conventional gain measurement signal processing unit shown in FIG. Items having the same function are denoted by the same reference numerals, and description thereof is omitted.

In the conventional example of FIG. 18, the frequency of the digital filter is described as having a band-pass characteristic that allows the same frequency as the frequency of the sine wave generated by the excitation signal generation unit 260 to pass and blocks other components. Has been. However, the frequency of the sine wave was not specified. Specifically, as explained in FIG. 17, “the frequency of this sine wave is the resonance frequency of the scanner actuator to be controlled, the frequency of various noises of the amplifier, the frequency region where the influence of friction is remarkable, etc. The transfer function is set to a frequency that exhibits a double integral characteristic as an inertial body ", but it is not specified how many.

  In the present invention, the frequency is set to 1 kHz which is not affected by the resonance frequency of the galvano scanner and is not affected by friction. More specifically, since the influence of friction starts to manifest from 500 Hz or less experimentally, a frequency higher than this frequency is desirable. Further, since the resonance frequency of the galvano scanner varies depending on the structure of the scanner, considering the applicability to many scanners, the anti-resonance of the primary resonance is low and is about 2 kHz. Then, it is set to 1 kHz. Of course, you may set to the frequency specialized to the characteristic of each galvanometer scanner.

  As described above, the digital filters 273a and 274a in FIG. 5 have a bandpass characteristic that allows a frequency of 1 kHz to pass and blocks other components. Further, the frequency of the sine wave generated by the excitation signal generation process 260 of FIG. 1 is 1 kHz.

  In the conventional example of FIG. 17, the amplitude of the sine wave is only described as a small amplitude, and the amplitude is not specified. There is no description suggesting the optimum amplitude. On the other hand, in the present invention, the amplitude of the sine wave is optimized from the gain fluctuation measurement result using the amplitude as a parameter in order to reduce the gain variation. Specifically, the amplitude of the sine wave of the present invention is the minimum specified by the number of diffraction gratings attached to the scale disk 122 of the angle detector 120 for angle detection of the galvano scanner 100 of FIG. The amplitude of the sine wave is larger than the rotation angle so that the swing shaft 111 (mirror 130, scale disk 122) rotates. Specifically, if the number of diffraction gratings attached to the scale disk 122 is, for example, m, the distance P between diffraction gratings determined by the number of diffraction gratings of the scale disk is P = 360 / m (deg ). In general, in such an angle detector 120, the space between diffraction gratings is further multiplied by n by a phase interpolation circuit using a Fourier image method. Thereby, high resolution is realized.

Here, when the gain is measured by setting the amplitude of the sine wave to P / 6 (deg) which is smaller than the distance between diffraction gratings P (deg), a narrow range “3P (deg) where no gain fluctuation occurs. However, it has become clear from the results of periodic component analysis that errors that vary with a specific period are included. More specifically, it has become clear that fluctuations in the fluctuation period of P / 2, P / 3, and P / 4 appear in the gain measurement result. This is presumed to be an interpolation error caused by multiplication in the phase interpolation circuit.

  Therefore, as a result of an experiment using the amplitude of the sine wave as a parameter, it was found that if the amplitude is smaller than the interstitial distance P (deg), the measurement result becomes larger due to the influence of the interpolation error. . On the other hand, when the sine wave amplitude becomes larger than the interstitial distance P, the spatial resolution is lowered accordingly. From this, it was found that 2P to 3P (deg) is appropriate for the amplitude of the sine wave. Therefore, in this embodiment, the amplitude of the sine wave is set to 2P to 3P (deg).

  A second embodiment will be described with reference to FIGS. In the first embodiment, since the diagnosis is performed by referring to the gain diagnosis table pattern (FIG. 3) created in advance for the gain change feature (pattern), the degree of deterioration cannot be evaluated in common. It was. In this embodiment, therefore, a diagnosis can be performed from a gain change amount by a common procedure, and a function indicating the degree of deterioration is provided. A specific procedure is shown in FIG. Steps S101 to S105 are the same as those in the first embodiment, and steps S154 and after show a new procedure.

  Specifically, in step S154, the gain diagnosing unit calculates the difference between the previous gain and the current gain, and normalizes the gain fluctuation with the previous measurement result. Here, the previous gain is approximated by a quaternary approximate expression, and the difference between the approximate expression and the gain measured this time is normalized by the previous gain. Then, a standardized maximum value of gain fluctuation, ΔG, is obtained.

Next, in step S155, the gain fluctuation ΔG is classified into four levels according to the magnitude of the value, and the diagnosis result to be displayed is determined based on the magnitude. Specifically, it is as follows.
(A) When ΔG <0.3%: Display of “Normal” (b) When 0.3% <ΔG <0.5%: Display of “Needs monitoring” (c) 0.5% <ΔG Case: A quaternary approximation formula is created using the gain of the current measurement, and the new gain approximation formula and the magnitude of the gain fluctuation ΔGn of the current measurement result are displayed in two categories.
・ If ΔGn <0.5%: Renewal of gain ・ If 0.5% <ΔGn: Display measures according to gain change pattern

  Here, in the case of (c) 0.5% <ΔG, a fourth-order approximation formula is created using the gain of the current measurement, and the new gain approximation formula and the magnitude of the gain fluctuation ΔGn of the current measurement result are used. It is classified into two and displayed. This is because, by updating the gain approximation formula, if the error from the current measurement value is 0.5% or less, the variation in settling can be suppressed to a predetermined value or less by using a new gain. It is. In other words, if the gain is changed from the previous measurement result to the new measurement result (gain) this time, the positioning error can be kept within the allowable range of the apparatus.

On the other hand, even if the gain approximation formula is updated, if the error from the measured value does not fall below 0.5%, it is assumed that factors other than the gain are dominant. The corresponding countermeasure (FIG. 8) is displayed. Here, ΔG is selected as 0.5% as the reference value, but it is obvious that the value may be changed according to the required positioning accuracy. In addition, the determination of the pattern in S105 is before S154, but in S155, 0.5% <
If the process of S105 is performed only in the case of ΔGn, the number of pattern determinations can be reduced, so that determination can be made more efficiently. Further, the process of S105 can be replaced with the same process as shown in FIGS. 4b and 4c.

  FIG. 8 shows a gain diagnosis table of the second embodiment. This indicates that the gain fluctuation amount obtained from each gain change amount is calculated according to the procedure of FIG. 9, and the diagnosis result is commonly displayed from the magnitude of the gain fluctuation amount ΔG. Then, as in the procedure of FIG. 9, when the gain fluctuation amount at the previous time (shipment time) and the current time (diagnosis) is larger than 0.5%, the approximate expression of the gain is updated from the current measurement gain. Then, if the error of the current measurement value is 0.5% or less with respect to the updated gain approximation formula, the positioning accuracy can be kept within a predetermined value by using the updated gain approximation formula. The display of the diagnosis result indicates “gain update”. If the gain fluctuation does not fall within 0.5%, other factors are the main causes, so the countermeasures shown in FIG. 8 corresponding to the characteristics of each gain change are displayed. . Specifically, for example, in the case of FIG. 8 (5), the gain fluctuation rate ΔG of the previous time and the current time exceeds 0.5%, and therefore the gain approximate expression is updated. Next, if the gain fluctuation ΔGn (the error between the approximate expression and the current measurement value) is smaller than 0.5%, “gain update” is displayed. “Replace” is displayed.

  As described above, in this embodiment as well, the galvano scanner can be diagnosed as in the first embodiment. Therefore, as in the first embodiment, the deterioration diagnosis of positioning accuracy, that is, the machining accuracy is performed. Can be diagnosed, and the degree of the deterioration can be displayed in four stages. Since the degree of deterioration is displayed in four stages, the maintenance of the scanner is facilitated, and high processing accuracy can be maintained and measures for deterioration of positioning accuracy can be easily performed.

A third embodiment will be described with reference to FIGS. The present embodiment is a galvano scanner control device that can perform not only gain diagnosis but also position deviation signal diagnosis, and is intended to provide a more accurate diagnosis function (performance) by using two diagnosis functions together. Yes.
FIG. 10 is a block diagram of a scanner servo mechanism constituting the galvano scanner control device 510 in the third embodiment. The description of the components having the same functions as those of the first embodiment shown in FIG. The difference between the third embodiment and the first embodiment is that, in the third embodiment, a position deviation signal diagnostic unit 430 is provided with the gain diagnostic unit 2 as shown in FIG.

  In this embodiment, gain diagnosis is performed by the gain diagnosis unit 2 in the same manner as in the first embodiment. Therefore, as in the first embodiment, the galvano scanner can be diagnosed from the gain fluctuation. This galvano scanner diagnostic function can prevent deterioration of the processing accuracy of the galvano scanner, so that high reliability can be ensured. In addition, since the degree of deterioration and the cause of deterioration can be known, planned maintenance and countermeasures can be performed, and high machining accuracy can be maintained without impairing productivity. Further, in the third embodiment, by providing the position deviation diagnosis unit 430, it is possible to more accurately grasp the presence / absence of the deterioration of positioning accuracy and the degree of the deterioration as compared with the first embodiment.

  Using FIG. 11, two diagnosis examples combining gain diagnosis and position deviation signal diagnosis are shown. FIG. 11 (1) shows the variation in position deviation in the case of (4) of the gain diagnosis table shown in FIG. 3, that is, when the gain fluctuation is only near the center. The position deviation indicates the deviation between the target position and the actual laser position (detection position of the angle detector 120). The positional deviation variation shows time on the horizontal axis and the positional deviation signal variation on the vertical axis. This variation measurement of the positional deviation signal indicates the variation of the positional deviation signal in the operation of sending the mirror in one direction at a specific interval (hereinafter referred to as the feeding operation). In FIG. 11 (1), in gain diagnosis, fluctuations at the time of shipment and diagnosis are small (0.3% or less), but when viewed in terms of variations in the position deviation signal, the variation is moderate compared to the normal case. An example is shown. For example, when the allowable variation in position deviation is set to be less than ± 2 μm, the following countermeasures are displayed. In the case of gain diagnosis, the factor can be estimated, but the factor cannot be estimated if the position deviation varies.

・ Position deviation variation ± 0.5μm ⇒ Normal (no deterioration)
・ Position deviation variation ± 1μm ⇒ Monitoring required ・ Position deviation variation ± 2μm ⇒ Gain update, bearing replacement ・ Position deviation variation ± 3μm or more ⇒ Gain update, bearing replacement

  In this way, even if the gain change alone is small and the progress of deterioration cannot be found, it is possible to find the deterioration of the positioning accuracy of the galvano scanner from the variation of the position deviation signal, and the degree of deterioration can be further increased. It is possible to display accurately. In this example, the degree of deterioration in gain diagnosis is small, but “gain update” is displayed as an example where the variation in the position deviation signal is moderate, for example, about ± 3 μm.

  FIG. 11 (2) shows the variation in position deviation in the case of (5) of the gain diagnosis table shown in FIG. 3, that is, when the gain fluctuates greatly between the center and the left and right. In the example, gain diagnosis has a large variation (1.0% or more) at the time of shipment and at the time of diagnosis, and variation in position deviation signal is also large. In this way, the results of gain fluctuation diagnosis and position deviation diagnosis become the same, so that the accuracy of diagnosis can be improved.

100 Galvano Scanner 110 Electromagnetic Oscillation Actuator 111 Oscillation Shaft 112 Bearing 113 Permanent Magnet 120 Angle Detector 121 Detection Unit 122 Scale Disk 130 Mirror 215 Command Signal 242 Current Position 400 Gain Diagnosis Unit 410 Diagnosis Database 420 Display Unit 430 Position Deviation Signal Diagnosis 500 A galvano scanner control device having a gain diagnosis function (first embodiment)
510 Galvano Scanner Control Device with Position Deviation Diagnosis Function (Second Embodiment)

Claims (4)

In the control device of the galvano scanner, which operates an actuator that swings the mirror based on the deviation between the command signal and the current position, and controls the emission angle of light incident on the mirror.
Measuring means for measuring a gain change of the actuator according to a swing angle;
Storage means for storing a gain change measured prior to actual operation by the measurement means;
Correction means for correcting the operation amount of the actuator so as to eliminate the gain change stored in the storage means during actual operation;
Comparing the measurement results of the actuator after a predetermined time with a plurality of predetermined patterns and determining a pattern close to the measurement results from the plurality of types of patterns;
A control device for a galvano scanner, comprising: a diagnosis unit for diagnosing deterioration in processing accuracy of a galvano scanner from the determined pattern ; and display means for displaying a diagnosis result, factor estimation, and countermeasures. The control device for a galvano scanner according to claim 1,
A display means for displaying a diagnosis result of processing accuracy deterioration of the galvano scanner, a factor estimation thereof, and a countermeasure with reference to the variation in position deviation as well as the characteristics of the gain change with time. A control device for a galvano scanner.   2. The galvano scanner control device according to claim 1, wherein the display of the countermeasure is changed in stages according to the magnitude of the gain fluctuation rate. In the control device of the galvano scanner, which operates an actuator that swings the mirror based on the deviation between the command signal and the current position, and controls the emission angle of light incident on the mirror.
Measuring means for measuring a gain change of the actuator according to a swing angle;
Storage means for storing a gain change measured prior to actual operation by the measurement means;
Correction means for correcting the operation amount of the actuator so as to eliminate the gain change stored in the storage means during actual operation;
From the characteristics of the gain change over time, a diagnosis unit for diagnosing the processing accuracy deterioration of the galvano scanner, and display means for displaying the diagnosis result, factor estimation, and countermeasures are provided.
In a control device for a galvano scanner,
Diagnosis of processing accuracy degradation of the galvano scanner
Comparing the measurement results of the actuator after a predetermined time with a plurality of predetermined patterns and determining a pattern close to the measurement results from the plurality of types of patterns;
A control method for a galvano scanner, characterized in that a diagnosis result, factor estimation and countermeasures are displayed from the determined pattern.

Images