JP2004322149A - Laser beam machining mechanism, and control method and production facility for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser beam machining mechanism which realizes enhancement of machining accuracy of a laser beam machining mechanism, such as a laser beam machining mechanism for a printed circuit board, and a control method and production facility for the same. <P>SOLUTION: The laser beam machining mechanism is equipped with a laser oscillator 8 for outputting a laser beam, a work positioning means for introducing the laser beam to a set area of a work, a control section 2 for controlling the laser beam positioning means and a detecting section 11 for detecting the machining state of the work. The signal from the detecting section is inputted to the control section and the deviation between the central position of the distribution of the machining area by the laser beam machining and the set position is calculated in the control section and the data of the machining position of the laser beam is corrected based on the deviation. The machining accuracy is thereby enhanced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser processing apparatus, a control method thereof, and a production facility.
[0002]
[Prior art]
In recent years, electronic devices have been required to be smaller and lighter. To achieve this, high-density mounting of electronic components using IVH (inner via hole), which is an interlayer connection circuit of multilayer printed circuit boards, is progressing. . This will increase the number of IVH holes formed on a single multilayer printed circuit board, reduce the diameter, and increase the density. In order to respond to this, the hole processing precision of the laser processing equipment for printed circuit boards will be increased. In particular, there is a demand for higher accuracy of galvano devices used for positioning of laser light.
[0003]
FIG. 13 shows an outline of a laser processing machine for printed circuit boards. The control device 101 controls the laser oscillator 102, the galvano device 104, and the processing table 106. The laser oscillator 102 outputs a laser beam 103 for processing. The galvano device 104 positions the laser beam 103 by a mirror attached to a biaxial motor. The fθ lens 105 condenses the laser light 103. The camera 107 detects the position of a positioning mark on the printed circuit board 108 and a processing hole for position correction. The processing table 106 is mounted with a printed circuit board 108 to be processed. The operation of the laser processing machine for printed circuit boards will be described. The laser beam 103 output from the laser oscillator 102 is positioned by the galvano device 104, condensed by the condenser lens 105, irradiated to a predetermined position of the printed circuit board 108, and drilling is performed.
[0004]
FIG. 12 shows the configuration of a conventional laser processing apparatus for printed circuit boards. A machining program, machining conditions, parameters, and the like are input to the input unit 1 from the outside. The control unit 2 includes a laser control unit 4, a processing table control unit 5, a galvano control unit 6, and a distortion correction unit 7. The main control unit 3 receives a program, machining conditions, and parameters from the input unit 1, analyzes these data, and outputs operation commands to the laser control unit 4, the machining table control unit 5, and the galvano control unit 6, respectively. When a laser output command is input from the main control unit 3 to the laser control unit 4, a laser output command signal is output to the laser oscillation unit 8. Further, status information such as the laser output state of the laser oscillation unit 8 is output to the main control unit 3. When the laser output command signal is input from the laser control unit 4, the laser oscillation unit 8 outputs laser light according to the laser output signal. Further, a laser output monitor signal or the like is output to the laser controller 4. When a control parameter such as a command speed or a machining table position command is input from the main control unit 3 to the machining table control unit 5, position control is performed and a motor drive command signal is output to the machining table unit 9. Further, the motor position information and the like are output to the main control unit 3. When the motor driving command signal is input from the processing table control unit 5, the processing table unit 9 drives the motor in accordance with the motor driving command signal. In addition, a motor position detection signal is output to the machining table control unit 5. When distortion correction data and a galvano position command are input from the main control unit 3 to the distortion correction unit 7, distortion correction is performed on the position command, and then the corrected position command is output to the galvano control unit 6. Control parameters such as command speed are input from the main control unit 3 to the galvano control unit 6. When a galvano movement command after distortion correction is input from the distortion correction unit 7, position control is performed and a galvano drive command signal is output to the galvano scanner unit 10. In addition, position information and the like are output to the main control unit 3. When the galvano scanner unit 10 receives a galvano drive command signal from the galvano control unit 6, it drives the galvano motor in accordance with the galvano drive command signal. Further, the position detection signal of the galvano motor is output to the galvano control unit 6. When a position detection command is input from the main control unit 3, the position detection unit 11 detects the position of the machining hole and outputs the detection result to the main control unit 3. The main control unit 3 calculates the displacement amount of the machining hole from the detection position of the position detection unit 11, creates distortion correction data, and outputs it to the distortion correction unit 7.
[0005]
This is the operation of the laser processing apparatus for printed circuit boards. When a program, processing conditions, and parameters are input from the input unit 1, the main control unit 3 creates a processing table position command and outputs it to the processing table control unit 5. Position control is performed with the unit 8 at the target position. After the positioning of the processing table unit 8 is completed, the main control unit 3 creates a galvano position command and outputs it to the distortion correction unit 7. The distortion correction unit 7 performs distortion correction of the galvano position command, and then outputs the galvano position command after distortion correction to the galvano control unit 6. The galvano control unit 6 controls the position of the galvano scanner unit 10 at the target position. After the positioning of the galvano scanner unit 10 is completed, the main control unit 3 creates a laser output command, outputs it to the laser control unit 4, and emits laser light from the laser oscillation unit 8. By repeating these, hole machining is performed on the entire workpiece.
[0006]
In the laser processing apparatus for printed circuit boards, the positional accuracy of the processing hole is required to be within ± 20 μm. Therefore, when converted from the value, the processing accuracy of the galvano device needs to be within ± 10 μm. Therefore, this ± 10 μm is the specified accuracy of the galvano device. If there is even one processing hole whose processing accuracy does not fall within the specified accuracy in the printed circuit board, the circuit formed by the hole becomes defective, and the entire substrate becomes defective. Therefore, in the galvano apparatus, it is necessary to ensure the specified accuracy in all processed holes.
[0007]
When positioning the laser beam by combining the galvano device and the fθ lens, geometric distortion occurs on the processing plane. Therefore, in order to perform highly accurate positioning, it is necessary to control the position of the galvano device with a position command in which these distortions are corrected. Further, since a shift and expansion / contraction misalignment also occurs at the processing position of the galvano apparatus, it is necessary to correct this misalignment. In the galvano apparatus, these correction data are created in advance, and the position command is corrected with the correction data during galvano driving, and then the galvano scanner is driven.
[0008]
As a method of creating these correction data, there is a method of calculating correction data from the target position and the actual misalignment of the machining hole. Although this correction method can correct geometric distortion and positional deviation of the galvano device itself, it takes time to create correction data because the number of machining holes to be measured is large. However, there is almost no change in the geometric distortion, and only the positional deviation of the galvano device always occurs. Therefore, there is no practical problem even if the positional deviation of the galvano device is corrected at a constant period. Therefore, as a method of correcting the position deviation of the galvano device, the shift amount and expansion / contraction rate are calculated from the displacement amount of the machining hole at the galvano origin position and the displacement amount of the outermost machining hole, and the distortion is calculated by the shift amount and the expansion / contraction rate. There is a method of correcting correction data (see, for example, Patent Document 1).
[0009]
As described above, the laser beam can be accurately positioned at a predetermined position as programmed.
[0010]
[Patent Document 1]
Japanese Patent Laid-Open No. 2000-71087
[Problems to be solved by the invention]
Now, there is a large shift in the position shift of the galvano device. This is because the displacement of the positioning position due to the variation of the detection position sensor of the galvano device and the displacement of the relative position between the camera of the processing device and the galvano device are included. Therefore, correction of shift deviation is important.
[0012]
However, the repeatability of detecting the position of the processing hole at the galvano origin position is about ± 2 μm because it is affected by the repeatability of the galvano device, camera, processing table, processing shape, and the like. Therefore, when the shift amount is obtained from the positional deviation amount of only the machining hole at the galvano origin position, the whole machining hole is displaced by this repetition accuracy. Further, since there is a deviation in the alignment between the galvano origin position and the fθ lens center position, the amount of deviation of the machining hole at the galvano origin position does not coincide with the center of the accuracy distribution of the machining hole. For this reason, even if the shift amount of the distortion correction data is corrected from the displacement amount of the machining hole at the galvano origin position, all the machining holes may not fall within the specified accuracy.
[0013]
An object of the present invention is to solve the above-mentioned problems and to provide a laser processing apparatus capable of performing high-precision processing, a control method therefor, and production equipment.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, a laser processing apparatus of the present invention includes a laser oscillator that outputs laser light, laser light positioning means that guides the laser light to a set portion of a workpiece, and the laser light positioning means. A control unit for controlling, a detection unit for detecting a machining state of the workpiece, a signal from the detection unit is input to the control unit, and the central position of the distribution of the processing site by laser processing in the control unit And the position indicating the machining position of the laser beam is corrected based on the deviation.
[0015]
Further, in the control method of the laser processing apparatus of the present invention, the step of guiding the laser beam to the set part of the workpiece based on the set data, the step of detecting the position of the processing part of the workpiece, A step of calculating a positional deviation amount between the set part and the actual machining position, a step of determining whether the positional deviation amount is within an allowable range, and calculating a center value of the positional deviation amount from each positional deviation amount within the allowable range. A step of calculating, as a correction value, a positional deviation between the calculated center value and the set portion, and a step of correcting data set based on the correction value.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[0017]
FIG. 1 is a configuration diagram of a galvano device according to an embodiment of the present invention. The configuration of the galvano device of FIG. 1 is obtained by adding a shift amount calculation unit 12 to the configuration of the conventional galvano device of FIG. The shift amount calculation unit 12 receives parameters such as a detection method and an allowable range of the deviation amount from the main control unit 3. When the processing hole detection position is input from the position detection unit 11, the shift amount is calculated from the detection position, the shift amount is calculated from the shift amount, and the shift amount is output to the distortion correction unit 7. Next, the shift amount calculation process of the shift amount calculation unit 12 will be described.
[0018]
FIG. 2 shows an accuracy distribution diagram of the processed holes. Laser machining is performed, the machining position of the machining hole is detected by the position detection unit 11, the amount of displacement from the command position is calculated, and the distribution of the displacement is plotted. Here, the same 50 mm square as that of the galvano processing range is used, and the grid processing is performed at intervals of 5 mm, and the positional deviation amount of 121 processing holes is plotted. In the distribution of FIG. 2, since there is a processed hole whose positional deviation amount exceeds ± 10 μm of the specified accuracy, it is necessary to correct the distortion correction data. In FIG. 2, the positional deviation of the origin hole machined at the origin position of the galvano machining area is (−1.4 μm, 1.2 μm), which is deviated from the center of the distribution. A case will be described in which distortion correction data is corrected using the position deviation amount of the origin hole as a shift correction amount. Since the minimum control unit of the galvano apparatus is 1 μm, the shift amount is in 1 μm increments. Therefore, the shift amount is (1 μm, −1 μm), and this value is added to the distortion correction data of the distortion correction unit 7.
[0019]
FIG. 3 shows the accuracy distribution when the positional deviation amount is measured again under the same conditions as in FIG. When the machining is actually performed again, the distribution shape is not exactly the same due to the repetition accuracy of the galvano apparatus, but here, the positional deviation distribution of FIG. 2 is shifted by the shift amount for easy understanding. In the accuracy distribution of the processed holes in FIG. 3, the positional deviation of the origin hole is almost zero, but the specified accuracy cannot be ensured because there are processed holes whose positional deviation amount exceeds ± 10 μm. Even if correction is performed again by the same method, the positional deviation amount does not fall within ± 10 μm. Therefore, in the accuracy distribution of the machining holes in FIG. 2, the intermediate position between the maximum value and the minimum value of the positional deviation amount in each axis direction is (−6.1 μm, 1.1 μm). When the distortion correction data is corrected using the position shift amount as a shift correction amount, the shift amount becomes (6 μm, −1 μm). FIG. 4 shows the accuracy distribution of the misaligned hole after correction using the intermediate position as the shift amount. In the accuracy distribution of the processed holes in FIG. 4, the positional deviation amounts of all processed holes are within ± 10 μm, and the specified accuracy of the galvano device is secured by correcting the distortion correction data with the intermediate position as the shift amount. The processing device can be made highly accurate.
[0020]
Next, FIG. 5 shows an accuracy distribution diagram of the processed holes when there are large positional shifts by only a few processed holes. The large misalignment amounts of several points in FIG. 5 are when the position detector 11 performs illegal position detection. When image recognition is used for the position detection method of a processed hole, the position cannot be detected correctly if foreign matter such as dust overlaps the processed hole or a flaw and a processed hole of the workpiece overlap. In the accuracy distribution of the machined hole in FIG. 5, the intermediate position between the maximum value and the minimum value of the misalignment amount in each axis direction is (3.8 μm, 3.3 μm). When the distortion correction data is corrected using the position shift amount as a shift correction amount, the shift amount becomes (−4 μm, −3 μm). FIG. 6 shows the accuracy distribution of the surrounding holes after correcting the intermediate position as the shift amount. The machined hole shown in FIG. 5 that shows a large misalignment is not reproducible because it is generated due to dust or scratches, and does not show the same large misalignment amount when drilled again and measured. . Therefore, in the accuracy distribution of the processed holes in FIG. However, since the shift amount is calculated and corrected at the intermediate position obtained from the large positional deviation amount in FIG. 5, the accuracy distribution is worse than in FIG. 5, and the specified accuracy of ± 10 μm cannot be secured.
[0021]
Therefore, in the accuracy distribution of the machined hole in FIG. 5, if the amount of positional deviation is outside the allowable range, the positional deviation data is deleted as having been illegally detected by position detection, and then the intermediate position is calculated. There are a method of deleting a misalignment hole outside the allowable range, such as making data beyond a certain distance from the average position out of the permissible range, calculating a standard deviation of the misalignment amount, and omitting a large standard deviation. FIG. 7 shows the accuracy distribution of the processed hole when a point with a large positional deviation is removed from FIG. In the accuracy distribution of the machined hole in FIG. 7, the intermediate position between the maximum value and the minimum value of the positional deviation amount in each axial direction is (−6.0 μm, 5.4 μm). When the distortion correction data is corrected using the positional deviation amount as the shift correction amount, the shift amount becomes (6 μm, −5 μm). FIG. 8 shows the accuracy distribution of the machined hole after correcting this intermediate position as the shift amount. In the accuracy distribution of the processed holes in FIG. 8, the positional deviation amounts of all the processed holes are within ± 10 μm, and after correcting the positional deviation outside the allowable range, the distortion correction data is corrected using the intermediate position as the shift amount. Thus, the specified accuracy of the galvano device can be ensured and the processing device can be made highly accurate.
[0022]
FIG. 9 shows a case where the average position is calculated with the accuracy distribution of the processed holes in FIG. In FIG. 9, there is an average position around the center of the mass of distribution. This is because there are 121 misalignment measurement points, and even if there is a large misalignment amount of 4 points, it is averaged. In the accuracy distribution of FIG. 9, the average position of the displacement amount is (−5.7 μm, +3.8 μm). When the distortion correction data is corrected using the positional deviation amount as the shift correction amount, the shift amount becomes (6 μm, −4 μm). FIG. 10 shows the accuracy distribution of the machined hole after correcting the average position as the shift amount. In the accuracy distribution of the machining holes in FIG. 10, the positional deviation amounts of all the machining holes are within ± 10 μm, and even if the positional deviations outside the allowable range are not removed, the distortion correction data is obtained with the average position as the shift amount. By correcting, the specified accuracy of the galvano device can be ensured and the processing device can be made highly accurate. In particular, when the accuracy distribution is sparse and it is difficult to distinguish the misalignment holes outside the allowable range, the distortion correction data can be optimally corrected by using the average position as the shift amount. Even when the average position is set as the shift amount, the average position can be corrected with higher accuracy by removing the position deviation outside the allowable range.
[0023]
Next, the operation of the galvano apparatus will be described. The operation at the time of drilling is the same as that of the conventional apparatus. The shift amount calculation operation will be described. FIG. 11 shows a flowchart.
[0024]
When starting, in step 1, a calculation method and the like are input as parameters from the main control unit 3 to the shift amount calculation unit 12. In step 2, the machining hole position is measured. In step 3, the amount of machining hole deviation is calculated from the measured hole position and the coordinate position of the table. In step 4, it is determined whether or not the hole to be measured is complete. If there are still measurement holes, return to step 2. If the measurement hole is finished, go to Step 5. In step 5, it is determined whether the displacement amount is within an allowable range. If it is within the allowable range, go to Step 6. If it is outside the permissible range, go to Step 7. In step 6, the misregistration amount is stored. In step 7, the end of data is determined. If the data is complete, go to Step 8. If there is still data, go back to step 5. In step 8, the shift amount is calculated by a preset shift amount calculation method. In step 9, it is determined whether the calculated shift amount is within an allowable range. If it is within the allowable range, the shift amount is output to the distortion correction unit at step 10. If it is outside the allowable range, an alarm is output to the main control unit in step 10 and the process is terminated.
[0025]
It should be noted that not only correcting the distortion correction data using the shift amount calculated as described above but also correcting the processing table position command using the shift amount can similarly correct the shift amount of the positional shift. In addition, if it is possible to select the optimal one of the intermediate position and the average position according to the state of the accuracy distribution, the distortion correction data can be corrected with the optimal shift amount, so that the specified accuracy of the galvano device is reliably ensured, The processing apparatus can be made highly accurate. [0026]
【The invention's effect】
As is apparent from the above description, according to the present invention, since the processing position of the laser beam is corrected from the center position of the distribution of the processing holes, highly accurate laser processing can be realized.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a laser processing apparatus according to a first embodiment of the present invention. FIG. 2 is an accuracy distribution diagram of processed holes before correction. FIG. 3 is an accuracy distribution diagram of processed holes after correction according to the prior art. FIG. 4 is an accuracy distribution diagram of a machined hole after intermediate position correction in the present invention. FIG. 5 is an accuracy distribution diagram of a machined hole when there is a defective detection hole before correction. Accuracy distribution diagram of the machined hole [Fig. 7] Accuracy distribution diagram of the machining hole when the detection failure hole is removed before correction [Fig. 8] Machining hole after correction at the intermediate position excluding the detection failure hole before correction FIG. 9 is an accuracy distribution diagram of machining holes at an average position before correction. FIG. 10 is an accuracy distribution diagram of machining holes after correction at an average position in the present invention. ] Configuration diagram of conventional laser processing equipment [Fig. 13] Schematic diagram of laser processing equipment Description]
DESCRIPTION OF SYMBOLS 1 Program input part 2 Control apparatus 3 Main control part 4 Laser control part 5 Processing table control part 6 Galvano control part 7 Distortion correction part 8 Laser oscillation part 9 Processing table part 10 Galvano scanner part 11 Position detection part 12 Shift amount calculation part 101 Control device 102 Laser oscillator 103 Laser light 105 fθ lens 106 Processing table 107 Camera 105 Laser light 106 Condensing lens 108 Printed circuit board

Claims (13)

A laser oscillator that outputs a laser beam; a laser beam positioning unit that guides the laser beam to a set portion of the workpiece; and a control unit that controls the laser beam positioning unit; and a processing state of the workpiece A detection unit for detecting is provided, a signal from the detection unit is input to the control unit, and the control unit calculates a deviation between the center position of the distribution of the processing site by laser processing and a set position, A laser processing apparatus for correcting data indicating a processing position of laser light based on the above. The laser processing apparatus according to claim 1, wherein a table for positioning a workpiece is provided as laser beam positioning means, and the table is controlled by a control unit. The laser processing apparatus according to claim 1, wherein a scanner mirror disposed on a laser beam path from a laser oscillator to a workpiece is provided as laser positioning means, and the scanner mirror is controlled by a control unit. As a laser positioning means, a table for placing a workpiece and positioning the workpiece and a scanner mirror disposed on a laser beam path from a laser oscillator to the workpiece are provided, and the table and the scanner mirror are controlled by a control unit. The laser processing apparatus of Claim 1 controlled by. A laser oscillator that outputs laser light, a laser control unit that controls driving of the laser oscillator, a table that places a workpiece and positions the workpiece, and a table control unit that controls driving of the table A scanner mirror disposed on a laser beam path from the laser oscillator to the workpiece, a scanner mirror control unit for controlling driving of the scanner mirror, and an input for inputting data indicating a machining part of the workpiece A main control unit that inputs a signal from the input unit and controls the laser control unit, the table control unit, and the scanner mirror control unit, and detects the processing state of the workpiece, and the detection unit A shift amount calculation unit that calculates a deviation between the center position of the distribution of the processing site by laser processing and the set position by inputting a signal from the laser processing is provided, and the deviation is provided to the main control unit And force, a laser processing apparatus for correcting the data indicating the working position of the laser beam. The laser processing apparatus according to any one of claims 1 to 5, wherein a specific range is defined as a distribution of processing parts for calculating a center position, and a processing part other than the specific range is not used for calculation. The laser processing apparatus according to any one of claims 1 to 6, wherein an intermediate position between a maximum value and a minimum value of a positional deviation amount on each axis in orthogonal coordinates is obtained, and this point is set as a central position. The laser processing apparatus according to any one of claims 1 to 6, wherein an average position of the distribution of processing parts is a center position. 2. An intermediate position between a maximum value and a minimum value of a positional shift amount on each axis in orthogonal coordinates is obtained, and this point is set as a center position, or an average position of distribution of processed parts is set as a center position. The laser processing apparatus in any one of 6. Based on the set data, the step of guiding the laser beam to the set part of the workpiece, the step of detecting the position of the processed part of the workpiece, and the positional deviation between the set part and the actual machining position A step of calculating an amount, a step of determining whether the positional deviation amount is within an allowable range, a step of calculating a central value of the positional deviation amount from each positional deviation amount within the allowable range, and the calculated central value are set. A method for controlling a laser processing apparatus, comprising: calculating a positional deviation from a region as a correction value; and correcting data set based on the correction value. 11. The method of controlling a laser processing apparatus according to claim 10, wherein as the step of calculating the center value, an intermediate value between the maximum value and the minimum value of the positional deviation amount on each axis in the orthogonal coordinates is obtained. The method for controlling a laser processing apparatus according to claim 10, wherein an average position of the distribution of the processing site is obtained as the step of calculating the center value. A production facility in which the laser processing apparatus according to claim 1 is arranged, a supply means for supplying a workpiece to the laser processing apparatus, and a processing means for processing the processed workpiece.

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