Laser beam machining apparatus

Abstract

To provide a laser beam machining apparatus capable of enhancing machining efficiency while preventing occurrence of machining defects.SOLUTION: A laser beam machining apparatus comprises: a laser oscillator that oscillates a laser; a galvanometer scanner that positions an irradiation position of a laser beam emitted from the laser oscillator; and a control unit that controls the laser oscillator and the galvanometer scanner. The control unit includes a notch filter that attenuates, at a preset frequency, a drive signal transmitted to the galvanometer scanner. Upon input of a laser machining command to perform laser machining on a plurality of machining positions, the control unit measures a resonant frequency of the galvanometer scanner before performing laser machining on an initial machining position (S2, S4), and executes a process of setting a frequency to be attenuated by the notch filter to the measured resonant frequency of the galvanometer scanner (S6).SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a laser processing device. [Background technology]

[0002] Generally, laser processing machines that irradiate a laser to perform hole processing on a workpiece such as a printed circuit board are widely known as drilling machines. Such laser processing machines position the laser using a galvanometer scanner to perform hole processing with high precision.

[0003] Furthermore, when the galvanometer scanner is operated at a specific frequency, an oscillation phenomenon occurs, making it impossible to perform positioning control. Therefore, some laser processing devices are configured to prevent the oscillation phenomenon from occurring by setting a notch filter for the oscillation frequency.

[0004] However, the above-mentioned oscillation frequency may change due to deterioration of the adhesive that secures the mirror of the galvano scanner, temperature changes, etc. For this reason, to prevent the frequency attenuated by the notch filter from deviating from the oscillation frequency, a laser scanner has been proposed that sets a timer when setting the frequency of the notch filter, and then resets the frequency of the notch filter after a certain period of time has elapsed (see Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-276128 Summary of the Invention [Problem to be solved by the invention]

[0006] However, as described above, when the frequency of resetting the notch filter frequency is set by a timer, if the timer is set for a long time, the detection of frequency deviations may be delayed, which may result in processing defects, while if the timer is set for a short time, the laser processing device will be stopped for a long time, which will result in reduced processing efficiency.

[0007] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a laser processing device that can improve processing efficiency while preventing processing defects. [Means for solving the problem]

[0008] One aspect of the present invention is a laser processing apparatus comprising: a laser oscillator that emits a laser; a galvanometer scanner that positions the irradiation position of the laser emitted from the laser oscillator; and a control unit that controls the laser oscillator and the galvanometer scanner, wherein the control unit has a notch filter that attenuates a frequency set from a drive signal to the galvanometer scanner, and when a laser processing command to perform laser processing on multiple processing positions is input, the control unit measures the resonant frequency of the galvanometer scanner before performing laser processing on the first processing position, and performs a process of setting the frequency attenuated by the notch filter to the measured resonant frequency of the galvanometer scanner.

[0009] One aspect of the present invention is a laser processing device comprising: a laser oscillator that emits a laser; a galvanometer scanner that positions the irradiation position of the laser emitted from the laser oscillator; and a control unit that controls the laser oscillator and the galvanometer scanner, wherein the control unit has a notch filter that attenuates a frequency set from a drive signal to the galvanometer scanner, and when a laser processing command to perform laser processing on a plurality of processing positions is input, when processing is performed on the last processing position among the processing positions within the scan area of ​​the galvanometer scanner, the control unit measures the resonant frequency of the galvanometer scanner and executes a process of setting the frequency attenuated by the notch filter to the measured resonant frequency of the galvanometer scanner. [Effects of the Invention]

[0010] According to the present invention, it is possible to improve processing efficiency while preventing processing defects. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a laser processing device according to an embodiment of the present invention. [Figure 2] FIG. 3 is a schematic diagram showing the control system of the galvanometer control unit. [Figure 3] 10 is a flowchart showing a setting process of a notch filter. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, a laser scanning device and a laser processing device according to an embodiment of the present invention will be described with reference to the drawings. In the following description, the X-axis direction and the Y-axis direction are based on the state when the processing object is viewed in a plan view.

[0013] <Schematic configuration of laser processing equipment> 1, the laser processing apparatus 100 according to this embodiment is a laser processing apparatus that drills holes in a printed circuit board 1 as a processing object placed on a processing table 2 that is movable in the X and Y axes, and is equipped with, in addition to the processing table 2 described above, a laser oscillator 3, a galvanometer scanner 4, a focusing (Fθ) lens 5, and an overall control unit 6. Note that the processing object by the laser processing apparatus 100 is not limited to a printed circuit board, and other workpieces may also be processed.

[0014] The laser oscillator 3 is, for example, a carbon dioxide (CO2) laser oscillator, and the generated laser pulse (laser) L1 is emitted from the laser oscillator 3.

[0015] The galvanometer scanner 4 is disposed on the optical path of the laser, and scans the laser pulse L1 in the X-axis and Y-axis directions to position the irradiation position on the printed circuit board 1. More specifically, the galvanometer scanner 4 includes scanner units for scanning in the X-axis direction and for scanning in the Y-axis direction, and each scanner unit includes a mirror (hereinafter also referred to as a scanner mirror or a galvanometer mirror), an axial rotation motor as a drive source for driving and rotating the mirror, and a rotary encoder for detecting the rotation angle of the mirror. These scanner units for scanning in the X-axis direction and for scanning in the Y-axis direction are disposed so that the rotation axes of the mirrors are orthogonal to each other, and are configured so that the irradiation position of the laser beam can be positioned within a predetermined scan area by adjusting the rotation angle of each mirror.

[0016] The overall control unit 6, which serves as a control unit, is an overall control unit that controls the entire laser processing apparatus 100, and includes a laser oscillation control unit 7 and a galvanometer control unit 8. The laser oscillation control unit 7 outputs an oscillation command signal S to the laser oscillator 3 to command the oscillation and attenuation of the laser beam in the laser oscillator 3, and controls the intensity, pulse width, etc. of the laser pulse L1 emitted from the laser oscillator 3. The galvanometer control unit 8 outputs a galvanometer control signal G to the galvanometer scanner 4, and controls the rotation angle of the mirror of the galvanometer scanner 4. The galvanometer control unit 8 also receives an angle detection signal K that indicates the angle of the galvanometer scanner 4.

[0017] Therefore, when the laser processing apparatus 100 irradiates a laser pulse to a predetermined position on the printed circuit board 1 to perform hole drilling, for example, a galvanometer control signal G is output from the galvanometer control unit 8 to the galvanometer scanner 4 according to the processing position on the printed circuit board 1, and the laser irradiation position is positioned.

[0018] Then, when positioning by the galvanometer scanner 4 is completed, the laser oscillation control unit 7 outputs an oscillation command signal S to the laser oscillator 3, and the laser oscillator 3 emits a laser pulse L1 with a laser intensity and pulse width according to the oscillation command signal S toward the galvanometer scanner 4.

[0019] The laser pulse L1 is deflected in the X and Y axis directions by the galvano scanner 4 and is incident on the condenser lens 5. The laser pulse L1 is then condensed by the condenser lens 5 at a predetermined position on the printed circuit board 1 as a laser pulse L2, and holes are drilled in the printed circuit board 1.

[0020] The above-mentioned laser oscillation control unit 7 and galvano control unit 8 may each be realized as one function (process) of the control program of the laser processing apparatus 100, or may be realized as an independent circuit. For this reason, the overall control unit 6 includes at least one storage unit in which the above-mentioned control program is stored, and at least one CPU (computing unit) that executes the control program.

[0021] <Galvano control unit> Next, the schematic configuration of the galvanometer control unit 8 will be described with reference to Fig. 2. As shown in Fig. 2, the galvanometer control unit 8 has a machining operation command unit 17, an adder (subtractor) 10, a compensator 11, a notch filter 12, a D / A converter 13, a current controller 14, a vibration analysis unit 15, and a parameter correction unit 16.

[0022] The machining operation command unit 17 is configured to output a target angle signal P corresponding to the irradiation position of the laser beam (i.e., the machining position of the workpiece) to the adder 10. The adder 10 outputs a deviation signal between the target angle signal P input from the machining operation command unit 17 and the angle detection signal K input from the angle detector 9 to the compensator 11.

[0023] The compensator 11 aims to stabilize the entire servo system, and employs, for example, a phase lag / lead compensator, and performs feedback control to position the galvano scanner 4 using the angle detection signal K. Note that if the required target value tracking characteristics cannot be obtained using only the feedback control system, a separate feedforward compensator may be added.

[0024] The drive signal for the galvano scanner 4 output from the compensator 11 is input to a notch filter 12, which filters the drive signal so as to attenuate the set resonance frequency of the galvano scanner 4. The signal filtered by the notch filter 12 is then converted into an analog signal by a D / A converter 13 and input to a current controller 14. Based on the input analog signal, the current controller 14 outputs a galvano control signal G to the galvano scanner 4. As a result, the mirror of the galvano scanner 4 is positioned at a predetermined rotation angle, making it possible to drill a hole at the processing position on the printed circuit board 1.

[0025] <Notch filter frequency setting process> On the other hand, the notch filter 12 has a function of attenuating the resonant frequency of the galvano scanner 4, but the resonant frequency of the galvano scanner 4 may fluctuate due to factors such as deterioration of adhesives attached to the components that make up the galvano scanner 4. For this reason, the galvano control unit 8 is configured to be able to execute a setting process for setting (resetting) the frequency to be attenuated by the notch filter 12. Specifically, the galvano control unit 8 includes the vibration analysis unit 15 and parameter correction unit 16 described above as means for setting the frequency to be attenuated by the notch filter 12. The frequency setting process of the notch filter 12 will be described in detail below with reference to FIGS. 2 and 3.

[0026] When a laser processing command (laser processing job) is input to the overall control unit 6, the galvanometer control unit 8 first checks whether it is the start of processing or the last processing time in the scan area (step S1 in FIG. 3). That is, it determines whether it is before processing the first processing position (the drilling position in this embodiment) of the laser processing command (the start of processing), or when processing the last processing position among the processing positions present in the scan area of ​​the galvanometer scanner 4 (the final processing time in the scan area).

[0027] If it is not the start of the above-mentioned processing or the final processing in the scan area (No in S1), the galvano control unit 8 outputs the target angle signal P from the processing operation command unit 17 as described above, positions the irradiation position of the laser beam as usual, and performs normal processing in cooperation with the laser oscillation control unit 7 (step S3). That is, in this case, the galvano control unit 8 does not perform the frequency setting process of the notch filter 12.

[0028] On the other hand, when the above-mentioned machining start or final machining within the scan area is being performed (Yes in S1), the galvanometer control unit 8 first connects the switch SW in FIG. 2 and performs an operation to check the resonance frequency of the galvanometer scanner 4 (steps S2 and S4). In the operation to check the resonance frequency, when the switch SW is turned on, the machining operation command unit 17 outputs a drive signal (target angle signal P) to the galvanometer scanner 4 to perform machining and response wave measurement. That is, the target angle signal P causes the galvanometer scanner 4 to perform a normal machining operation via the above-mentioned compensator 11, notch filter 12, D / A converter 13, and current controller 14 (step S2). Note that when the galvanometer scanner 4 performs a normal machining operation in step S2, if it is final machining within the scan area, a laser pulse is emitted from the laser oscillator 3 to perform laser machining. However, at the start of machining, no laser pulse is emitted from the laser oscillator 3 at the stage of step S2.

[0029] Next, the angle detector 9 outputs an angle detection signal K of the galvano scanner 4 operated by the target angle signal P to the vibration analysis unit 15. This angle detection signal K is a signal that indicates the angle of the galvano scanner 4 from when the galvano scanner 4 starts to operate until the galvano scanner 4 stops and settles. Then, the vibration analysis unit 15 analyzes the angle detection signal K to extract the resonance frequency (step S4). More specifically, the vibration analysis unit 15 extracts the resonance frequency from the waveform of the angle detection signal K using, for example, the Prony method or the like.

[0030] Then, the vibration analysis unit 15 determines whether the extracted resonant frequency is equal to or less than a predetermined threshold value previously obtained through an experiment (i.e., determines whether the extracted resonant frequency is lower than a known resonant frequency) (step S5). If the extracted resonant frequency is not equal to or less than the predetermined threshold value (No in step S5), the parameter correction unit 16 does not reset the frequency of the notch filter 12, and the frequency setting of the notch filter 12 is maintained.

[0031] On the other hand, if the extracted resonant frequency is equal to or lower than the predetermined threshold value (Yes in step S5), it is determined that there is a discrepancy between the current notch filter frequency setting and the resonant frequency of the galvano scanner 4. Then, the processing is stopped, and the parameter corrector 16 resets the frequency set in the notch filter 12 as the attenuated frequency to the extracted resonant frequency (step S6).

[0032] In this way, the frequency setting of the notch filter 12 is completed. When the frequency setting of the notch filter 12 is reset, the galvano control unit 8 then determines whether or not it is time to start processing (step S7). If it is time to start processing (Yes in step S7), the notch filter 12 with the reset frequency setting is used to reposition the laser irradiation position with respect to the processing position within the scan area, and then laser processing is performed (step S8).

[0033] After the above-mentioned process, the galvanometer control unit 8 determines whether processing of all scan areas in the substrate has been completed (step S9), and if not (No in step S9), controls the galvanometer scanner 4 to move to the next hole position and repeats the operation from step S1 (step S10). Then, when processing of all holes has been completed (Yes in step S9), processing of the scan area is completed.

[0034] <Summary> a laser oscillator (3) that oscillates a laser; a galvanometer scanner (4) for positioning the irradiation position of the laser emitted from the laser oscillator (3); a control unit (6) that controls the laser oscillator (3) and the galvano scanner (4), The control unit (6) has a notch filter (12) that attenuates a frequency set in a drive signal to the galvano scanner (4), and when a laser processing command to perform laser processing on a plurality of processing positions is input, the control unit (6) measures a resonance frequency of the galvano scanner (4) before performing laser processing on the first processing position, and executes a process of setting the frequency to be attenuated by the notch filter (23) to the measured resonance frequency of the galvano scanner (4). A laser processing device (100) characterized by:

[0035] In this way, by measuring the resonance frequency of the galvano scanner 4 before a machining command is input and the first machining operation is performed, and setting the frequency at which the notch filter 12 attenuates to the measured resonance frequency, it is possible to prevent a discrepancy between the frequency setting of the notch filter 12 and the resonance frequency of the galvano scanner 4, thereby preventing machining defects caused by the discrepancy. In particular, because the frequency setting process of the notch filter 12 is performed before machining at the first machining position, the possibility of producing a defective product due to a machining defect can be reduced. Furthermore, because the frequency setting process of the notch filter 12 is performed at an appropriate frequency and using the time before machining starts, when there is often ample time, it is possible to minimize a decrease in machining efficiency and improve machining efficiency.

[0036] When a laser processing command to perform laser processing on a plurality of processing positions is input, the control unit (6) measures the resonance frequency of the galvano scanner (4) when processing the last processing position among the processing positions within the scan area of ​​the galvano scanner (4), and executes a process of setting the frequency attenuated by the notch filter (12) to the measured resonance frequency of the galvano scanner (4).

[0037] In this way, by measuring the resonant frequency of the galvano scanner 4 when starting to process the substrate and when processing the final processing position in the scan area and setting the frequency at which the notch filter 12 attenuates to the measured resonant frequency, it is possible to prevent a mismatch between the frequency setting of the notch filter 12 and the resonant frequency of the galvano scanner 4, thereby preventing processing defects caused by such a mismatch. In particular, because the resonant frequency of the galvano scanner 4 is measured during final processing in the scan area, the frequency setting of the notch filter 12 can be adjusted before starting processing in the next scan area.

[0038] Furthermore, by measuring the resonance frequency of the galvano scanner 4 during final processing within a scan area, the time from when processing of one scan area is completed until transition to the next scan area can be utilized to detect the resonance frequency and reset the notch filter. Specifically, the resonance frequency can be detected and the notch filter can be reset by utilizing the time from when positioning of the irradiation position at the final processing position of the previous scan area is completed until positioning of the irradiation position at the processing start position of the next scan area is started.

[0039] Note that the time required to move the irradiation position between processing positions within the same scan area (the time required for the galvano scanner 4 to move) is much shorter than the time required to move the irradiation position between processing positions between different scan areas, which requires the movement of the processing table 2. Therefore, the time required for simple movement between processing holes is insufficient for the resonant frequency detection and notch filter resetting processes. In this case, since the frequency setting of the notch filter 12 cannot be reset, if there is a mismatch between the set frequency of the notch filter 12 and the resonant frequency of the galvano scanner 4, an error will occur in any hole (processing position) within that scan area, and all holes after the error will also be found to be error-prone, resulting in the entire substrate to which that scan area is assigned being discarded. However, in this embodiment, as described above, the set frequency of the notch filter 12 can be reset using the time required for transition to the next scan area. This allows the substrate to be partially discarded while retaining the usable portion within the scan area. This, combined with the fact that the frequency setting process of the notch filter 12 is performed at an appropriate frequency, minimizes the occurrence of processing defects.

[0040] In the above-described embodiment, the frequency setting process of the notch filter 12 is performed at the start of processing and at the time of final processing within the scan area (after processing at the processing position one position before the final processing position within the scan area, and between processing at the final processing position and positioning at the first position of the next scan area), but the frequency setting process of the notch filter 12 may be performed only at either the start of processing or at the time of final processing within the scan area as described above. [Explanation of symbols]

[0041] 3: Laser oscillator 4: Galvanometer scanner 6: Control unit (overall control unit) 12: Notch filter 100: Laser processing equipment

Claims

1. a laser oscillator that oscillates a laser; a galvanometer scanner for positioning an irradiation position of the laser emitted from the laser oscillator; a control unit that controls the laser oscillator and the galvano scanner, the control unit has a notch filter that attenuates a frequency set in a drive signal to the galvano scanner, and when a laser processing command to perform laser processing on a plurality of processing positions is input, measures a resonance frequency of the galvano scanner before performing laser processing on a first processing position, and executes a process of setting the frequency to be attenuated by the notch filter to the measured resonance frequency of the galvano scanner. A laser processing device characterized by:

2. When a laser processing command to perform laser processing on a plurality of processing positions is input, the control unit measures a resonance frequency of the galvano scanner when processing the last processing position among the processing positions within a scan area of ​​the galvano scanner, and executes a process of setting the frequency to be attenuated by the notch filter to the measured resonance frequency of the galvano scanner.

2. The laser processing device according to claim 1.

3. a laser oscillator that oscillates a laser; a galvanometer scanner for positioning an irradiation position of the laser emitted from the laser oscillator; a control unit that controls the laser oscillator and the galvano scanner, the control unit has a notch filter that attenuates a frequency set in a drive signal to the galvano scanner, and when a laser processing command to perform laser processing on a plurality of processing positions is input, measures a resonance frequency of the galvano scanner when processing the last processing position among the processing positions within a scan area of ​​the galvano scanner, and executes a process of setting the frequency to be attenuated by the notch filter to the measured resonance frequency of the galvano scanner. A laser processing device characterized by:

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