JP6167307B2 - Laser processing equipment - Google Patents

Description

  The present invention relates to a laser processing apparatus that performs drilling or the like on a substrate using a laser, and more particularly to improvement of dynamic positioning accuracy of a galvano scanner used in the laser processing apparatus.

  In recent years, with the miniaturization, high integration, and complex modularization of parts, the drilling of base materials has become increasingly precise, and in order to respond to this, drilling using a laser is increasing. The galvano scanner used in such a laser processing apparatus scans the laser beam on the surface of the workpiece by controlling the rotation of a mirror that reflects the laser beam by a rotation drive unit. A high positioning accuracy with respect to the position command is required at the timing of emitting the laser pulse.

  However, the positioning sensor used at the time of positioning has a characteristic that the output signal fluctuates due to changes in the surrounding environment such as temperature and humidity and changes over time. Therefore, in order to maintain long-term machining accuracy that can accurately machine microscopic holes in a predetermined position, the fluctuation of the output signal of the positioning sensor is corrected, and the rotational position of the galvano scanner is determined by the position command signal. It is necessary to always match the command position.

  An example of the prior art for this problem will be described with reference to the drawings.

  FIG. 19 is a block diagram showing a schematic configuration of a laser processing apparatus according to the prior art. In the figure, a position command generator 901 outputs command position data for rotating the mirror in the galvano scanner 908 to a target predetermined rotation position as a position command signal. On the other hand, the position sensor 909 incorporated in the galvanometer 908 outputs a rotational position of the galvanometer 908, that is, a position detection signal of the rotational angle of the mirror, and the position detection signal is sent from the position detector 910 to the actual rotational position of the mirror. Is converted into an actual position data signal indicating the output.

  The PID controller 902 PID (P: proportional, I: integral) so that the deviation between the position command signal output from the position command generator 901 and the actual position data signal output from the position detector 910 becomes zero. D: Differentiation) A control process is performed. Based on the deviation, a current command value at which the deviation becomes 0 is calculated and output as a current command signal.

  The current controller 903 controls the power amplifier 4 according to the deviation between the current command signal output from the PID controller 902 and the actual current data signal output by the current detector 907 detecting the current of the galvano scanner 908. Then, the operation is performed so that the current flowing from the current detector 907 to the galvano scanner 908 matches the current command signal.

The positioning time detection unit 905 arbitrarily sets a positioning completion width that assumes that the positioning of the galvano scanner 908 has been completed, and after the positioning process for the galvanometer 908 is started, the detection position from the position detector 910 indicates the positioning position described above. The completion of positioning is detected by detecting that it is within the completion width. (Including positioning time detection means for detecting the time required from the start of the positioning process of the galvanometer 908 to the completion of positioning as positioning time)
The position sensor fluctuation detector 911 detects the characteristic fluctuation of the position sensor 909 from the fluctuation of the positioning time detected by the positioning time detector 5.

The position sensor correction warning signal output means 912 outputs a warning signal indicating the necessity of correction for the characteristic fluctuation of the position sensor 909 when the position sensor fluctuation detector 911 detects the characteristic fluctuation of the position sensor 9. As means for obtaining information for detecting the characteristic fluctuation of the position sensor 909 by the fluctuation detector 911, current value integration means 906 for integrating the current value detected by the current detector 907 during the positioning process of one cycle is provided ( (See Patent Document 1).

JP 2001-228414 A

  However, in the laser processing apparatus according to the prior art, when a characteristic variation occurs in the output signal of the position sensor due to an environmental change or a change over time, positioning is measured based on an arbitrarily set positioning completion width. Even if it is possible to detect a change in the characteristics of the position sensor due to a change in time or a change in the integrated value of the current flowing through the galvanometer, and output a signal to warn of the necessity of correction work for the change in characteristics Since the amount and direction of change (whether overshooting or undershooting with respect to the command position) cannot be detected, there is a problem that correction work must be performed separately.

  Accordingly, an object of the present invention is to provide a laser processing apparatus that can improve the dynamic positioning accuracy of a galvano scanner.

In order to solve the above-mentioned problems, a laser processing apparatus according to the present invention starts with a laser oscillator that receives a laser pulse output command signal and emits laser light, and receives position command information and receives an operation command signal. A galvano scanner that positions the laser beam at a processing position of a workpiece, and a laser processing device that includes at least a control device that controls the laser oscillator and the galvano scanner, wherein the galvano scanner transmits the laser beam A reflecting galvanometer mirror, a galvano motor for changing the angle of the galvanometer mirror, an angle sensor for detecting the angle of the galvanometer mirror, angle information obtained from the position command information and the angle sensor, and a plurality of preset values. And a galvano controller for controlling the drive current of the galvano motor based on the parameters In addition, a parameter storage unit for storing the plurality of parameters is installed, the tracking data of the galvano scanner is measured with respect to an operation command of a predetermined measurement pattern, and the parameter is set corresponding to the characteristic value derived from the tracking data. The measurement pattern is a pattern for repeating a plurality of different movement pitches for a predetermined time .

  With the above configuration, in the laser processing apparatus according to the present invention, the galvano scanner is different by changing the parameter corresponding to the characteristic value derived from the follow-up data of the galvano scanner with respect to the operation command of the specific pattern measured in advance. Since the dynamic accuracy can be suppressed within a predetermined range with respect to changes in the movement pitch and the motor temperature, the dynamic positioning accuracy of the galvano scanner can be improved.

The block diagram which shows schematic structure of the laser processing apparatus which concerns on embodiment of this invention The block diagram which shows the detailed structure of the galvano scanner which concerns on embodiment of this invention Timing chart showing operation at the time of processing of the laser processing apparatus according to the embodiment of the present invention The flowchart which shows the optimization process of the galvano drive parameter of the laser processing apparatus which concerns on embodiment of this invention The graph which shows an example of the galvano tracking data measurement pattern which concerns on embodiment of this invention The graph which shows an example of the pattern for galvano tracking data measurement and tracking data of the laser processing apparatus which concerns on embodiment of this invention The graph which shows an example at the time of enlarging 5 mm pitch movement among the patterns for galvano tracking data measurement concerning an embodiment of the invention The graph which shows an example of the relationship between the deviation which concerns on embodiment of this invention, and an in-positive signal The graph which shows an example of calculation of settling time concerning an embodiment of the invention The graph which shows an example of the calculation process of the difference total value which concerns on embodiment of this invention The graph which shows an example of the calculation process of the difference total value which concerns on embodiment of this invention The graph which shows an example of the settling time at the time of 5-minute galvano operation | movement which concerns on embodiment of this invention The graph which shows an example of the settling time of 1 mm pitch at the time of 5-minute galvano operation | movement which concerns on embodiment of this invention The graph which shows an example of the difference total value at the time of 5-minute galvano operation | movement which concerns on embodiment of this invention The flowchart which shows an example divided into the case of the pass / fail of the characteristic value which concerns on embodiment of this invention The figure which shows an example of the change parameter which concerns on embodiment of this invention The graph which shows an example of the settling time of 1 mm pitch at the time of galvano operation for 5 minutes after parameter optimization concerning an embodiment of the invention The graph which shows an example of the difference total value at the time of galvano operation for 5 minutes after parameter optimization concerning an embodiment of the invention The block diagram which shows schematic structure of the laser processing apparatus which concerns on a prior art

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same components are denoted by the same reference numerals, and the description thereof may be omitted.

(Embodiment 1)
<Main configuration of laser processing equipment>
FIG. 1 is a block diagram showing a schematic configuration of a laser processing apparatus according to an embodiment of the present invention. As shown in FIG. 1, a laser processing apparatus 100 includes a laser oscillator 101, a laser beam 102, an acoustooptic device 103, an optical adjustment unit 104, a mirror 105, a galvano scanner 200, an fθ lens 106, and a processing. A table 108 and a control unit 300 are provided.

  The laser oscillator 101 receives the laser pulse output command signal 401 output from the control unit 300 and emits laser light 102. The laser beam 102 emitted from the laser oscillator 101 enters the acoustooptic device 103 and cuts only the peak portion. Thereafter, the beam is shaped into a beam diameter according to the processing purpose by an optical adjusting unit 104 having a mask changer or the like. The shaped laser beam 102 is guided to the galvano scanner 200.

  The galvano scanner 200 receives the galvano position command information 402 and starts its operation to position the laser beam 102. The laser beam 102 positioned by the galvano scanner 200 is condensed on the workpiece 107 by the fθ lens 106.

<Detailed configuration of galvano scanner>
FIG. 2 is a block diagram showing a detailed configuration of the galvano scanner according to the embodiment of the present invention.

  The galvano scanner 200 includes at least motor control means 202, parameter storage means 201, X-axis direction motor 211, X-axis direction mirror 221, X-axis direction encoder 241, X-axis direction amplifier 231, Y-axis direction motor 212, and Y-axis direction mirror. 222, a Y-axis direction encoder 242, and a Y-axis direction amplifier 232.

  The motor control unit 202 receives the galvano position command information 402 from the control unit 300, and calculates the rotation angle of the galvano motor 210 using the parameters stored in the parameter storage unit 201 based on the target value. The rotation angle of the galvano motor 210 is transmitted as a drive signal 404 to the drive amplifier 230 and is amplified as a current value by the drive amplifier 230 to drive and rotate the galvano motor 210.

  In the positioning control in the X-axis direction, the current is amplified by the X-axis direction amplifier 231 and sent to the X-axis direction motor 211. The X-axis direction motor 211 rotates based on the drive signal 404 from the motor control means 202. The rotation angle of the X-axis direction motor 211 is detected by the X-axis direction encoder 241 and sent to the motor control means 202 as the FB signal 405. The FB signal 405 is a signal that feeds back the current rotational position of the galvano motor 210. Therefore, since the signal can be uniquely converted into the angle of the galvano mirror 220 and thus the irradiation position of the laser beam 102, the FB signal 405 is treated as information that can be added to and subtracted from the galvano position command information 402 in the following description.

  The motor control unit 202 receives the FB signal 405 from the X-axis direction encoder 241, adjusts the drive signal 404 to be output, and controls the rotational position to coincide with the galvano position command information 402.

  The same control as in the X-axis direction is performed with respect to the Y-axis direction. The Y-axis direction motor 212 rotates based on the drive signal 404 from the motor control means 202. The rotation angle of the Y-axis direction motor 212 is detected by the Y-axis direction encoder 242 and sent to the motor control means 202 as the FB signal 405. The motor control unit 202 receives the FB signal 405 from the Y-axis direction encoder 242, adjusts the drive signal 404 to be output, and controls the rotational position to coincide with the galvano position command information 402. The X axis / Y axis positioning control is executed in parallel.

  In the present invention, the position control of the galvano motor requires high speed and high accuracy, and therefore feedforward type spatial prediction servo control (model prediction control) is performed instead of the conventional PID feedback control. Therefore, in the motor control means 202, a virtual galvano motor model is formed inside, and the control amount at the next time is determined by sequentially calculating while comparing with the actual value obtained at each time from the encoder 240. .

  The virtual galvano motor is programmed so that a parameter corresponding to an actual physical quantity is converted into a numerical value and stored in the parameter storage unit 201, and virtually operated with a certain algorithm. Examples of parameters to be stored include motor inertia, resistance, inductance, torque with respect to input current, gain thereof, and the like. The parameter storage unit 201 also stores model control parameters in addition to model construction. For example, as for torque control, there are a gain for determining an acceleration amount, a position of a braking point, a brake gain, and the like. All these parameters are collectively referred to as galvano drive parameters.

  Upon receiving the new galvano position command information 402, the motor control means 202 sets an optimal control trajectory from the current position and speed. After reaching the vicinity of the target position, the fastest trajectory is determined within a range where dynamic stable behavior can be performed. The driving conditions are determined so as to trace the optimal control trajectory using the parameters of the virtual galvano motor, and the actual galvano motor is driven as the drive signal 404.

  For a given command, an error is calculated from the position based on the feedback current when the motor is operated and the position calculated in the model. This error is incorporated in the calculation of the driving amount, thereby matching the operation of the virtual motor model with the actual motor operation.

  Note that the galvano driving parameters are optimized as a unit before the shipment inspection of the galvano scanner 200 alone, and are set to fall within a predetermined standard range. However, when the galvano scanner 200 is mounted on the laser processing apparatus 100 and operated, some parameters need to be optimized due to subtle changes in conditions.

<Operation during processing of workpieces by laser processing equipment>
The operation of the laser processing apparatus of the present invention configured as described above will be described with reference to the drawings.

  The laser oscillator 101 is sufficiently warmed up as necessary. The workpiece 107 is placed and fixed on the processing table 108 and moved to a predetermined processing area. In accordance with the processing program, the galvano scanner 200 is positioned so that the laser beam 102 is irradiated to a predetermined processing point. The laser beam 102 is irradiated as a pulse, and the workpiece 107 is processed, for example, drilling. The galvano scanner 200 is positioned so that the next processing point is irradiated with the laser beam 102. The workpiece 107 is processed by irradiating the laser beam 102 as a pulse. By repeating the above cycle, the entire workpiece 107 is processed.

  The operation described below is one cycle part in which the workpiece 107 is processed by one laser pulse.

  FIG. 3 is a timing chart showing an operation during processing of the laser processing apparatus according to the embodiment of the present invention.

  The galvano response 410 represents a deviation from the current rotational position with respect to the galvano position command information 402. Therefore, when new galvano position command information 402 is issued from the control unit 300 so as to position the laser beam 102 at the next processing point, the deviation from the current position becomes maximum, and positioning control of the galvano motor 210 is started. Then it gradually approaches zero. The galvano response 410 is calculated as a difference between the galvano position command information 402 instructed from the control unit 300 and the galvano position information 403 from the motor control means.

  Note that the galvano motor 210 includes two motors, an X-axis direction motor 211 and a Y-axis direction motor 212, but in the graphs of FIG.

  When the current rotational position of the galvano motor 210 approaches the galvano position command information 402 and the absolute value of the galvano response 410 becomes below a certain value, the positioning completion signal 411 is turned ON. A threshold value for turning ON the positioning completion signal 411 is determined in advance. A deviation that can be determined to be sufficiently close to the galvano position command information 402 in terms of the distance on the workpiece 107 based on the required machining accuracy is set as the threshold value. For example, the deviation of the galvano response 410 corresponding to about several μm in terms of the distance on the workpiece 107, specifically 5 μm, or 2 μm when higher accuracy is required may be set as the threshold value.

  When the positioning completion signal 411 is turned ON, after a predetermined waiting time (Te1 in the figure), the control unit 300 sets the laser command (laser pulse output command signal 401) to a period corresponding to the laser pulse width (Te2 in the figure). The laser oscillator 101 receiving the laser command outputs the laser beam 102. Since the laser oscillator 101 has rising and falling characteristics, the laser output has a profile as shown in the figure. After the laser command is turned off, the control unit 300 transmits the galvano position command information 402 of the next processing point to the galvano scanner 200 after a predetermined period (Te3 in the figure) has elapsed.

  When the next new galvano position command information 402 is issued after laser irradiation, the galvano response 410 becomes maximum again, and at the same time, the positioning completion signal 411 also changes from ON to OFF. In the figure, the section in which the positioning completion signal 411 is OFF corresponds to the galvano movement time, and the section in which the positioning completion signal is ON corresponds to the galvano stop time.

  Note that the galvo travel time varies depending on the travel distance. The setting of the width of the laser pulse can be adjusted depending on the processing conditions, and the times of Te1 to Te3 are set by the processing conditions. If Te1 to Te3 in the figure are made constant during the machining period, the galvano stop period becomes constant in each machining cycle.

<Optimization process for galvo drive parameters of laser processing equipment>
FIG. 4 is a flowchart showing a process for optimizing galvano drive parameters of the laser processing apparatus according to the embodiment of the present invention.

  The process for optimizing the galvano driving parameter is roughly divided into four processes.

  In the first step, the galvano scanner 200 is operated with a predetermined predetermined galvano tracking data measurement pattern, and the tracking data for the galvano position command information 402 is measured as a log at a constant cycle. Specifically, the operation command of the galvano motor 210 corresponding to the galvano tracking data measurement pattern is sent to operate the motor, and the log of the movement locus of the rotation angle and the positioning completion signal with respect to the galvano position command information 402 is acquired at a cycle of about 10 μs. (S01).

  In the second step, the total difference value and the settling time are calculated from the log of the tracking data and the ON / OFF timing of the positioning completion signal (S02).

  In the third step, it is checked whether the dynamic positioning accuracy of the galvano scanner is within a certain range from the calculated difference total value and the settling time result. If the dynamic positioning accuracy of the galvano scanner is within a certain range, it is determined that the current parameter is optimal and no change is necessary, and the process is terminated (S03).

  The fourth step is executed when the dynamic positioning accuracy of the galvano scanner does not fall within a certain range. Based on a predetermined change algorithm, a part of the galvano driving parameters is changed according to the rule, and the galvano operation is performed again (S04). The above flow is repeated to derive optimum driving parameters.

<First step of galvano drive parameter optimization>
In this step, the galvano scanner 200 is operated with a predetermined predetermined galvano tracking data measurement pattern, and the tracking data for the galvano position command information 402 is measured as a log at a constant cycle. The operation in the galvano tracking data measurement pattern is performed separately from the actual laser processing. For example, when checking the accuracy when starting the apparatus, when checking the accuracy during periodic inspection, or when checking the accuracy prior to actual machining. During this operation, the galvano scanner is driven in the same way as actual machining, but no laser pulse is emitted.

  FIG. 5 is a graph showing an example of a galvano tracking data measurement pattern according to the embodiment of the present invention. Since the galvano scanner 200 is composed of a pair of scans in the X-axis direction and Y-axis direction, the galvano drive parameter derivation step is performed independently. FIG. 5 shows a part of the galvano tracking data measurement pattern in the X-axis direction and shows the actual movement on the XY plane at the processing point. The circle on the 0 line in the Y coordinate in the figure is the command position included in the galvano position command information 402. An operation command is issued so that a step movement is performed at this pitch from a stationary state at the start point (X = -15, Y = 0). In this example, only the X direction is operated at a pitch of 5 mm.

  The galvano scanner 200 that has received the galvano position command information 402 performs a tracking operation toward the command position based on the existing galvano drive parameters stored in the parameter storage unit 201. The positioning completion signal is turned ON when it comes close to the command position up to a predetermined range. When a predetermined galvano stop time elapses, the galvano scanner 200 is caused to perform a step operation so as to give the next galvano position command information 402. This operation is reciprocated once.

  In the galvano tracking data measurement pattern, the above-described step operation is reciprocated once in a plurality of movement pitches. For example, 0.5 mm pitch step operation 1 reciprocation, 1 mm pitch step operation 1 reciprocation, 2 mm pitch step operation 1 reciprocation, 5 mm pitch step operation 1 reciprocation, and 0.5 mm to 5 mm are repeated again. At the first start point of each different pitch, a waiting time is provided so that it can be considered to be sufficiently stationary.

  The above is the galvano tracking data measurement pattern in the X-axis direction, but when adjusting the Y-axis direction motor, the galvano tracking data measurement pattern that performs the operation only in the Y-axis direction is set. In the following description, only the X-axis direction will be exemplified. Since the Y-axis direction is constant, for example, Y = 0, the position and the moving amount are values only in the X-axis direction and are displayed as scalar amounts.

  An explanation will be given by showing the data obtained in the experiment on the graph for the pattern of the galvano tracking data measurement pattern.

  FIG. 6 is a graph showing an example of a galvano tracking data measurement pattern and tracking data of the laser processing apparatus according to the embodiment of the present invention.

  The horizontal axis of the graph indicates time, and a partial period of the galvano tracking data measurement pattern is extracted. The vertical axis represents the position at the processing point of the galvano scanner 200, which is converted into the position on the processing surface according to the measurement pattern. The unit is [mm] millimeter. In the example, the reciprocating movement of 30 mm is repeated, and the command position and the moving locus are shown when the moving pitch is changed to 0.5 mm, 1 mm, 2 mm, and 5 mm for each reciprocation.

The step-like command position is indicated by a broken line, and the movement locus of the follow-up data is indicated by a solid line. However, in FIG. 6, since the time scale of the horizontal axis is rough compared to the tracking accuracy (dynamic position accuracy) of the galvano scanner , the difference cannot be expressed. Therefore, a graph in which part of the same data is cut out and the time axis on the horizontal axis is enlarged is shown. FIG. 7 is an enlarged view of the horizontal axis in FIG. 6 and shows the command position and the movement locus when moving at a pitch of 5 mm. The cut-off time is a period of 10 milliseconds from 0.16 seconds to 0.17 seconds. It can be seen that the position command indicated by the broken line is issued stepwise at a pitch of 5 mm, whereas the movement locus of the galvano motor moves to follow the position command.

  As described above, for the galvano tracking data measurement pattern that repeats the reciprocating operation in steps, the tracking data measured value is stored as a log at a predetermined time interval (for example, 10 μsec cycle), and at the same time, the positioning completion signal The ON / OFF state is also stored. This log is acquired until the period when the operation is started and the characteristics are stabilized. From experience, it is known from the temperature characteristics of the device that the characteristics stabilize in about 5 minutes (300 seconds).

<Second step of galvano drive parameter optimization>
In this step, the total difference value and the settling time are calculated from the log of the tracking data for the command position and the ON / OFF timing of the positioning completion signal. The calculation procedure of each characteristic value and its physical meaning will be described below using graphs.

  FIG. 8 is a graph showing an example of the relationship between the deviation and the in-positive signal according to the embodiment of the present invention. FIG. 8 is a cut-out portion that reverses the direction in a reciprocating operation with a pitch of 5 mm. Further, unlike FIG. 7, a value calculated from the difference between the command position and the movement locus is shown as a deviation. The vertical axis at the top of the graph shows the deviation and the unit is μm, but the scale is 2000 μm. Immediately after the command position is switched, the absolute value of the deviation is around 5000 μm (5 mm), from which it can be seen that the galvano operates and the deviation approaches zero. The plus / minus sign is calculated by subtracting the movement locus from the operation command, and corresponds to the direction of movement of the galvano scanner 200.

  At the bottom of the figure, a positioning completion signal that changes ON / OFF is shown at the same timing as the deviation graph. It is OFF when the deviation is large immediately after the command position is switched, and when the deviation approaches 0, the in-posit signal is turned ON. In this embodiment, the threshold is set to 2 μm.

  First, calculation of settling time will be described. The upper part of FIG. 9 is an enlarged view of the vertical axis of FIG. The unit is the same μm, but the scale is 2 μm. The in-posit signal shown at the bottom rises and becomes ON when the absolute value of the deviation becomes 2 μm, and falls and becomes OFF when the command position is switched and the deviation becomes large. The time from the fall of the positioning completion signal in FIG. 9 to the rise is the settling time. That is, the settling time is the time from when the command position is switched until the deviation becomes near 0 (2 μm or less in this example), and indicates the tracking time of the galvano scanner with respect to the command position.

  In order to use the settling time as a characteristic value, an average value is used in order to eliminate variations due to disturbance or the like. When a specific calculation method is shown in the figure, when the settling times T1, T2,... Tn and the number of movements are n times, the settling times for n times are obtained and the average value is obtained.

  Further, since the settling time is the tracking time of the galvano scanner until reaching the command position, it becomes a numerical value that varies depending on the magnitude of the movement distance, that is, the movement pitch. The settling time is calculated for each moving pitch, and the average value of the settling time for each pitch is calculated individually.

  Furthermore, the settling time changes over time from the start of operation of the apparatus. Therefore, every 30 seconds, the log settling time included in the 15 seconds before and after that is averaged for each pitch to obtain the settling time as the characteristic value at that time. The average of 0 to 15 seconds at 0 seconds, but the average of 15 to 45 seconds at 30 seconds, and 45 to 75 seconds at 60 seconds, all the corresponding settling times included in that time are used for calculation. Take. Note that 30 seconds is shown as an example, and is not limited to this as long as a sufficient average can be taken and a change with time can be observed.

  Next, calculation of the total difference value will be described. The total difference value is newly defined in the present application as a characteristic value that represents the dynamic accuracy of a period in which the positioning of the galvano scanner 200 is completed and is considered to be stationary. In FIG. 3, the period during which the positioning completion signal is ON is defined as the galvano stop time. In the galvano stop time, it is necessary to ensure the positional accuracy in processing. However, as can be seen from FIG. 9, the deviation fluctuates and does not become zero. In order to express this dynamic accuracy as an overall characteristic value, at least a direction in which the deviation approaches 0, a typical deviation amount in consideration of the positive and negative signs within the period when the positioning completion signal is ON, and within a specific period Statistical processing is required for the data.

  Hereinafter, the calculation procedure of the total difference value will be described using a graph. In calculating the total difference value, it is necessary to determine the moving direction of the galvano motor. In other words, it is necessary to determine whether the deviation has reached near zero from the negative direction or near zero from the positive direction. Here, the former is called the CW direction and the latter is called the CCW direction.

  FIG. 10 further expands the vertical axis and horizontal axis of FIG. 9 and shows the deviation during positioning and the detailed movement of the in-positive signal for one cycle. Since the log is recorded about every 10 μs, if the data is represented by dots, the scale of this graph becomes a discrete graph, but each dot is connected by a line so that the time series can be understood.

  In order to determine the moving direction, the deviation T1 and the deviation T2, which are deviations at times T1 and T2 before and after the rise of the in-positive signal, are compared.

When deviation T1−deviation T2> 0, the movement is in the CW direction.
When deviation T1−deviation T2 <0, movement in the CCW direction is performed. Next, a deviation N at Tn after a predetermined time has elapsed from the rising timing T1 of the positioning completion signal is obtained. This deviation N is a representative value of deviation within the galvano stop time. The set times of T1 to Tn vary depending on conditions such as the laser pulse width during the machining operation. In order to increase the accuracy and correlation in actual machining, the set times of T1 to Tn are set to the same timing as the waiting time from when the positioning completion signal is turned ON during actual machining until the actual laser irradiation.

  With the above processing, the value of the deviation N and the distinction between the CW direction and the CCW direction are calculated for every positioning cycle in the acquired log. Further, the deviation N is averaged separately for each pitch of the step operation. However, the average value of the deviation N of the cycle in the CW direction and the average value of the deviation N of the cycle in the CCW direction are totaled separately and averaged. Let CWN be the average value of deviation N in the CW direction, and CCWN be the average value in the CCW direction.

  The difference between CWN and CCWN calculated as described above is taken, and this is set as the difference total value D.

  The difference total value D is illustrated and described. FIG. 11 is a graph showing an example of a calculation process of the total difference value according to the embodiment of the present invention. As shown in FIG. 11, at each positioning timing, CWN representing the average value of the deviation N in the CW direction and CCWN representing the average value in the CCW direction from the deviation N at the timing corresponding to the movement direction determination and laser irradiation. Ask for. And D which represents a difference total value is calculated | required by taking the difference of CWN and CCWN. When the difference total value is positive, the galvano operation is overshooting with respect to the command position, and when the difference total value D is negative, it is undershooting with respect to the command position. Therefore, by using this total difference value as a criterion, it is possible to quantitatively detect not only whether or not the position sensor has changed, but also the changing direction and the changing amount.

  The total difference value also changes over time from the start of operation of the apparatus. Therefore, the calculation described above is performed for each pitch using the log included in the 15 seconds before and after every 30 seconds as in the case of the calculation of the settling time. The value is used as a total difference value as a characteristic value at the time. Note that 30 seconds is shown as an example, and is not limited to this as long as a sufficient average can be taken and a change with time can be observed.

  In this embodiment, for a galvano tracking data measurement pattern that repeats a reciprocating motion in a stepwise manner, a log of measurement values is stored up to the initially set time from the start of the operation, and the settling time is calculated from the log. The procedure for obtaining the total difference value by dividing time has been described. However, the method is not limited to such a procedure, and the method for calculating the differential total value and the settling time for each log data obtained by operating the galvano tracking data measurement pattern until the galvano motor temperature is saturated is obtained each time. It may be used.

<Third step of galvano drive parameter optimization>
In this step, it is inspected whether the dynamic positioning accuracy of the galvano scanner is within a certain range from the calculated settling time and the total difference value. If the dynamic positioning accuracy of the galvano scanner is within a certain range, it is determined that the current parameter is optimal and no change is necessary.

  12, 13, and 14, the galvano tracking data measurement pattern is operated for 5 minutes, and a total of 11 log data is acquired every 30 seconds immediately after the start, and for all acquired log data, The difference total value and settling time are calculated and graphed.

  First, the setting time determination (determination 1) will be described. FIG. 12 is a graph plotting the settling time calculated by dividing into 11 every 30 seconds in the galvano operation for 5 minutes. The vertical axis represents the settling time, and the horizontal axis represents the elapsed time from the start of the log processing. Since it is calculated for each step operation at four types of pitches, it is represented as four graphs, and eleven settling times are plotted for each pitch. Here, when the four graphs are compared, there is a difference that the settling time increases as the moving pitch increases, but it can be considered that the tendency with respect to the passage of time is almost the same. In the method of the present invention, the settling time for a 1 mm pitch is used to determine whether it is within a predetermined range.

  FIG. 13 is a graph obtained by enlarging the vertical axis and cutting out only the graph of settling time in the case of 1 mm pitch. The vertical axis represents the settling time, and the horizontal axis represents the elapsed time from the start of the log processing. Here, the calculated maximum value of the settling time during 1 mm pitch movement is defined as Tmax. The dotted line in the center of the graph indicates the allowable maximum value Tth of the settling time when moving by 1 mm pitch. The allowable maximum value Tth corresponds to a standard value as a device. Therefore, if Tmax is equal to or less than Tth, the value is within the standard, and if it exceeds the value, it is determined that the value is out of the standard range. In this example, the allowable maximum value Tth is defined as 500 μm as a standard value.

  Next, determination of the maximum difference value (determination 2) and determination of the minimum value (determination 3) will be described.

  FIG. 14 is a graph obtained by plotting the total difference value calculated by dividing into 11 every 30 seconds in the galvano operation for 5 minutes. The vertical axis represents the total difference value, and the horizontal axis represents the galvano operation time. The horizontal axis indicates the elapsed time from the start of the log processing. Since it is calculated for each step operation at four types of pitches, it is represented as four graphs, and eleven settling times are plotted for each pitch.

  Here, the maximum value and the minimum value of the total difference value calculated at all pitches and all times are obtained. In this example, it is determined from the calculated value of 4 × 11 points. In FIG. 14, the total difference value at the point of 90 seconds with a pitch of 0.5 mm is the largest, so this is selected and set as the maximum value Dmax of the total difference value. In the figure, since the total difference value at the point of 300 mm with a pitch of 5 mm is the smallest, this is selected as the minimum value Dmin of the total difference value.

  The dotted line at the top of the graph in FIG. 14 indicates the allowable maximum value Dthmax of the total difference value, and the dotted line at the bottom of the graph indicates the minimum allowable value Dthmin of the total difference value. The total difference value is a characteristic index of the present invention representing the dynamic position accuracy in the galvano stop time, and the limit value is set as a standard for both positive and negative directions. In this example, a range of ± 2 μm is set. Therefore, if Dmax is equal to or less than Dthmax, the value is within the standard, and if it exceeds the value, it is determined that the value is out of the standard range. If Dmin is equal to or greater than Dthmin, the value is within the standard, and if the value is less than that, it is determined that the value is out of the standard range.

<Fourth Step for Optimizing Galvo Drive Parameters>
This step is executed when the dynamic positioning accuracy of the galvano scanner does not fall within a certain range. That is, if any one of the determinations 1, 2, and 3 in the third step is not within the range defined as the standard, a part of the galvano driving parameters is determined according to the rules based on the change algorithm described below. change.

  FIG. 15 is a flowchart illustrating an example of dividing the case of the characteristic values according to the embodiment of the present invention. In this flowchart, parts corresponding to the same steps as those in the flowchart of FIG. 4 are denoted by the same reference numerals (S01 to S04). In particular, the third step (S03) is divided into determinations 1 to 3, and the determination results are divided into cases.

In decision 1, the allowable maximum values Tth and Tmax of the settling time are compared,
Tth ≧ Tmax
If so, proceed to OK, otherwise proceed to NG.

In the determination 2, the allowable maximum value Dthmax and Dmax of the total difference value are compared,
Dthmax ≧ Dmax
If so, proceed to OK, otherwise proceed to NG.

In determination 3, the allowable minimum value Dthmin and Dmin of the total difference value are compared,
Dthmin ≤ Dmin
If so, proceed to OK, otherwise proceed to NG.

  By the determination 1, the determination 2, and the determination 3, the current galvano characteristic is divided into eight patterns. Here, if all the determinations 1 to 3 are OK, the operation is finished without changing the parameters.

  Of the cases classified by OK / NG in the above three-stage determination, the number of cases where the parameter is changed is seven. FIG. 16 shows the seven patterns as a table. In each of the determinations 1 to 3, the case of OK is “◯”, and the case of NG is “X”. As patterns NG (1) to NG (7) in the pattern column, each of the NG patterns corresponds to the flowchart. A, B, C, and D in the change parameter column indicate parameter categories to be changed among the galvano drive parameters. The formula in the change amount column represents a formula for increasing or decreasing the parameter to be changed.

  Hereinafter, the change parameter will be described in detail.

  The change parameter A in the table is a parameter for changing the brake point of the drive current using the motor angle information as an argument, and is associated with a torque control-related parameter in the model predictive control. When the change direction is negative, the brake timing of the drive current is relatively delayed and the waveform tends to overshoot. This is used for the NG pattern (1) in the table.

  On the other hand, when the change direction of the change parameter A is positive, the brake timing of the drive current becomes relatively early and the waveform tends to undershoot. This is used for NG pattern (2) and NG pattern (6) in the table.

  The change parameter B is a parameter that changes the acceleration of the drive current using a second-order derivative of time of the motor angle information as an argument, and is associated with an inertia related parameter in the model predictive control. When the change direction is negative, the time for the drive current to reach the maximum value is shortened, and the settling time is shortened. However, since the current change becomes steep, the variation in the knitting difference at the time of settling at each pitch increases. It is used for NG pattern (4) and NG pattern (5) in the table.

  On the contrary, when the change direction of the change parameter B is positive, the time for the drive current to reach the maximum value becomes long and the settling time becomes long. However, since the current changes gradually, the variation in the knitting difference at the time of settling at each pitch becomes small. It is used for NG pattern (3) in the table.

  The change parameter C and the change parameter D are parameters that use the angle information of the drive current, the time derivative of the angle information, and the second-order derivative of the time of the angle information as arguments, and the role of changing the waveform deviation and the settling time during settling. There is. This is used for the NG pattern (8). In model predictive control, the parameters are related to inductance and resistance parameters.

  Further, the parameter change amount is obtained by multiplying the difference between the allowable value and the MAX value or the MIN value by a coefficient unique to each parameter. The parameters are changed as described above, and the galvano driving parameters are optimized by repeating the flowchart of FIG.

<Characteristics after optimizing galvo drive parameters>
An example of the galvano characteristic after the parameter optimization after executing the galvano tracking data measurement pattern again with the galvano driving parameter changed through the above four steps and OK in all the determinations 1 to 3 is shown in FIG. 18 shows. FIG. 17 is a graph showing an example of a settling time of 1 mm pitch during a 5-minute galvano operation after parameter optimization according to the embodiment of the present invention. FIG. 18 is a graph showing an example of the total difference value during the 5-minute galvano operation after parameter optimization according to the embodiment of the present invention.

  In FIG. 17, it can be seen that the settling time can be suppressed within a predetermined range with respect to the different movement pitches of the galvano scanner and changes in the motor temperature.

  In FIG. 18, it can be seen that the dynamic accuracy can be suppressed within a predetermined range with respect to different movement pitches of the galvano scanner and changes in the motor temperature.

  As described above, according to the laser processing apparatus of the present embodiment, the parameter is changed in accordance with the characteristic value derived from the follow-up data of the galvano scanner for the operation command of the specific pattern measured in advance. Since the dynamic accuracy can be suppressed within a predetermined range with respect to different movement pitches and motor temperature changes of the galvano scanner, the dynamic positioning accuracy of the galvano scanner can be improved.

  In the present embodiment, the allowable maximum value of the settling time is set only for the 1 mm pitch, but the allowable maximum value may be set at a plurality of pitches. Moreover, you may set with a pitch different from 1 mm pitch.

  Further, in the present embodiment, the case where the galvano operation is performed again for 5 minutes after the parameter change and the log is acquired has been described. It may be possible to perform a galvano operation for 5 minutes after confirming that it has come out as expected. In that case, unnecessary log data is not acquired, and parameter tuning time can be shortened.

  The laser processing apparatus according to the present invention can improve the dynamic positioning accuracy of the galvano scanner, and is useful in a laser processing apparatus that performs drilling or the like on a substrate using a laser.

DESCRIPTION OF SYMBOLS 100 Laser processing apparatus 101 Laser oscillator 102 Laser light 103 Acousto-optic element 104 Optical adjustment part 105 Mirror 106 f (theta) lens 107 Work piece 108 Processing table 200 Galvano scanner 201 Parameter storage means 202 Motor control means 210 Galvano motor 211 X-axis direction motor 212 Y-axis direction motor 220 Galvano mirror 221 X-axis direction mirror 222 Y-axis direction mirror 230 Drive amplifier 231 X-axis direction amplifier 232 Y-axis direction amplifier 240 Encoder 241 X-axis direction encoder 242 Y-axis direction encoder 300 Control unit 301 Laser command means 302 Determination means 303 Parameter change means 304 Calculation means 305 Storage means 306 Galvano command means 401 Laser pulse output command signal 402 Galvano position command Information 403 Galvano position information 404 Drive signal 405 FB signal 410 Galvano response 411 Positioning completion signal Tmax Maximum value of settling time Tth Maximum allowable value of settling time D Difference total value Dmax Maximum differential total value Dthmax Maximum allowable total differential value Dmin Minimum value of total difference value Dthmin Minimum allowable value of total difference value

Claims (4)

A laser oscillator that emits laser light in response to a laser pulse output command signal; a galvano scanner that receives position command information and receives an operation command signal to start operation and position the laser light at a processing position of a workpiece; A laser processing apparatus comprising a control device for controlling at least the laser oscillator and the galvano scanner,
The galvano scanner is obtained from a galvano mirror that reflects the laser light, a galvano motor that changes the angle of the galvano mirror, an angle sensor that detects the angle of the galvano mirror, the position command information, and the angle sensor. A galvano controller that controls the drive current of the galvano motor based on angle information and a plurality of preset parameters;
Installing a parameter storage unit for storing the plurality of parameters;
A laser processing apparatus that measures tracking data of the galvano scanner for an operation command of a predetermined measurement pattern and changes the parameter in accordance with a characteristic value derived from the tracking data ;
The laser processing apparatus, wherein the measurement pattern repeats a plurality of different movement pitches for a predetermined time. The laser processing apparatus according to claim 1 , wherein the characteristic value derived from the tracking data is a total difference value between a settling time and a laser pulse output command timing. An allowable maximum value of the settling time, determine the allowable maximum and minimum allowable value of the difference total values, according to claim 2 to perform processing to store the parameters in which the characteristic value is within the range of acceptable values Laser processing equipment. The allowable maximum value of the settling time, the allowable maximum value of the total difference value, and the allowable minimum value of the total difference value are divided into cases where the characteristic value is within or outside the range,
Define the parameters to be changed for each case classification,
Measure the characteristic value based on the changed parameters,
The laser processing apparatus according to claim 3 , wherein the parameter is changed until the characteristic value is within a range of all the allowable values.

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