JP5414782B2 - Laser processing equipment - Google Patents

Description

  The present invention relates to a laser processing apparatus for laser processing a workpiece using a pulse laser.

  A laser processing apparatus for laser processing a workpiece using a pulse laser processes the workpiece according to various processing conditions such as pulse energy and the number of burst shots (pulse shots) per hole. Such a laser processing apparatus needs to use a pulse laser with an appropriate frequency in order to perform stable laser processing. For this reason, when the laser processing device performs laser processing, it is necessary to accurately measure the pulse energy and adjust the output of the laser oscillation device based on the accurately measured pulse energy.

  For example, in the energy measuring method described in Patent Document 1, the pulse laser is intermittently oscillated by oscillating the pulse laser for several shots and then pausing. Then, when measuring the energy of the output pulse of the laser oscillator, the pulse energy E per shot is obtained by using the output power P, the oscillation frequency f, the oscillation time T1, and the pause time T2 of E = (P / f) × {T1 / (T1 + T2)}.

Japanese Patent Laid-Open No. 2003-90760

  However, in the above conventional technique, the operating conditions (oscillation duty ratio) are set within the capability range of the laser oscillation device, and the capability on the energy measuring device side is not taken into consideration. For this reason, there existed a problem that an energy measuring device might be damaged by beam irradiation more than the measuring capability of an energy measuring device.

  Further, if the operating condition of the laser oscillation device is determined without considering the capability of the energy measurement device, measurement accuracy may be deteriorated due to energy measurement at a small resolution. Further, although there are various phenomena with different time responses in the frequency characteristics of the pulse laser output from the laser oscillation device, the conventional technique can take into account only one phenomenon, so the energy measurement accuracy is poor. Thus, when the measurement accuracy of the pulse energy is poor, there is a problem that the output adjustment of the laser oscillation device cannot be accurately performed, and as a result, there is a difference in the quality of the laser processed hole.

  Further, when a wide range of workpieces are processed by one laser processing apparatus, a pulse laser is irradiated on the workpiece with various output powers. For this reason, in order to process a workpiece widely, it is necessary to use an energy measuring device having a wide output power range that can be measured on the workpiece irradiation surface. However, such an energy measuring device is expensive. was there.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a laser processing apparatus capable of performing laser processing with stable processing quality at low cost while preventing damage to a power meter.

In order to solve the above-described problems and achieve the object, the present invention provides a laser oscillation device that outputs a pulse laser and a transmission that transmits the pulse laser output from the laser oscillation device to a laser light irradiation surface of a workpiece. An optical system; a power measurement device for measuring the laser power of the pulse laser; and the pulse laser applied to the power measurement device and the workpiece within the oscillation capability range of the laser oscillation device and within the power measurement capability range of the power measurement device. And calculating the respective pulse irradiation patterns for the power measuring device and the workpiece based on the laser processing conditions of the workpiece, and controlling the laser oscillation device according to the pulse irradiation pattern At the same time, one shot calculated using the laser power measured by the power measuring device. And a control device that performs laser processing of the workpiece when the pulse energy of the pulse laser per unit is within a predetermined range set in advance, and the arithmetic unit has a predetermined number of drilling times for the workpiece The laser oscillation as the maximum value of the average frequency that is the number of pulse irradiation per unit time in the combined time of the beam-on time and the pause time that is the pause time for the laser oscillation for a predetermined time after the predetermined number of holes are drilled A first maximum average frequency at which the apparatus can oscillate, a second maximum average frequency when the pause time is assumed to be zero in pulse irradiation by the laser oscillation apparatus, and a power range set in the power measurement apparatus in a third of the maximum average frequency acceptable, was calculated, the maximum average frequency smallest from among the first to third maximum average frequency There are and calculates the pulse irradiation pattern.

  According to the present invention, since the pulse irradiation pattern is calculated so that the pulse laser is irradiated within the oscillation capability range of the laser oscillation device and the power measurement capability range of the power measurement device, the processing quality is prevented while preventing the power meter from being damaged. The stable laser processing can be performed at low cost.

FIG. 1 is a block diagram showing the configuration of the laser processing apparatus according to the first embodiment. FIG. 2 is a diagram for explaining a phenomenon in which pulse energy changes with frequency. FIG. 3 is a diagram for explaining a phenomenon in which pulse energy changes with frequency. FIG. 4 is a diagram for explaining a phenomenon in which pulse energy changes with frequency. FIG. 5 is a diagram for explaining a phenomenon in which pulse energy changes with frequency. FIG. 6 is a diagram for explaining a difference in time response of frequency characteristics. FIG. 7 is a diagram illustrating an example of a pulse irradiation pattern of a pulse laser irradiated to a workpiece by the laser processing apparatus. FIG. 8 is a flowchart showing an operation procedure of the laser processing apparatus according to the first embodiment. FIG. 9 is a flowchart showing an operation procedure of the laser processing apparatus according to the first embodiment. FIG. 10 is a flowchart showing an operation procedure of the laser processing apparatus according to the second embodiment. FIG. 11 is a flowchart showing an operation procedure of the laser processing apparatus according to the second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser oscillation apparatus 2 Transmission optical system 3 Mask 4 Work 5 Power meter 6 Control apparatus 7 Calculation part 8 I / F part 9 Work table 10 Laser processing apparatus Fg Average frequency Fm_ave Average positioning frequency Fp Burst frequency Ng Pulse group number Np Burst shot number

  Hereinafter, a laser processing apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing the configuration of the laser processing apparatus according to the first embodiment. The laser processing device 10 includes a laser oscillation device 1, a transmission optical system 2, a work table 9, a power meter (power measurement device) 5, a control device 6, a calculation unit 7, and an I / F (interface) unit 8. ing.

  The laser oscillation device 1 oscillates laser light and sends a pulse laser to the transmission optical system 2. A mask 3 for shaping the spatial distribution shape of the pulse laser is arranged in the transmission optical system 2. The transmission optical system 2 shapes the pulse laser output from the laser oscillation device 1 into a beam condition (spatial distribution shape and output time waveform) suitable for laser processing using a switching element such as a mask 3 or AQ, The shaped pulse laser is transmitted to the work table 9 side.

The work table 9 mounts a work 4 to be subjected to laser processing, and the power meter 5 has a laser output (pulse laser of the pulse laser) at the work irradiation surface position on the work table 9 (position where the work 4 is irradiated with laser). Measure the average output power P). Thereby, the laser processing apparatus 10 of this Embodiment becomes a structure which measures the average output power P of the pulse laser actually irradiated on the workpiece | work 4 after passing the mask 3. FIG. The average output power P of the pulse laser here is an average of the powers of a plurality of pulses irradiated to the workpiece irradiation surface position.

  Based on the processing conditions input to the I / F unit 8, the calculation unit 7 considers the measurement capability of the power meter 5 and the like, and applies pulse irradiation patterns (beam-on time Ton, beam pause time Toff, etc.) described later. Calculate. In addition, the calculation unit 7 determines the number of pulse irradiations per unit time (pulse average frequency <f> described later) in consideration of the measurement capability of the power meter 5 and the like. The calculation unit 7 is connected to the power meter 5 and calculates the average pulse energy E per shot using the average output power P and the pulse average frequency <f> measured by the power meter 5. Specifically, the average pulse energy E per shot is calculated by E = P / <f>. The calculation unit 7 sends the calculated pulse irradiation pattern to the control device 6.

  The I / F unit 8 is an interface (information input / output unit) between the laser processing apparatus 10 and an operator, and includes a mouse, a keyboard, and the like. Processing conditions and the like are input to the I / F unit 8, and the I / F unit 8 sends the input processing conditions to the control device 6 and the calculation unit 7.

  Based on the processing conditions sent from the I / F unit 8 and the pulse irradiation pattern calculated by the calculation unit 7, the control device 6 calculates the laser oscillation device 1, the transmission optical system 2, the work table 9, the power meter 5, and the calculation. The unit 7 and the I / F unit 8 are controlled.

  The laser processing device 10 controls the laser oscillation of the laser oscillation device 1 and the transmission optical system 2 so that the power meter 5 can be irradiated with a pulse laser corresponding to the measurement capability of the power meter 5 with the above-described configuration.

  The laser processing apparatus 10 uses the pulse energy on the workpiece irradiation surface as a processing condition when performing laser processing. For example, when drilling a workpiece 4, the laser processing apparatus 10 is arbitrarily selected by moving the work table 9 or operating a deflecting device (such as a galvano mirror (not shown)) that can be moved at high speed arranged in the transmission optical system 2. Drill the pattern position. The pulse irradiation pattern (irradiation schedule) at this time has an unspecified time interval depending on the interval of the hole machining position, the position moving speed of the deflecting device, and the like. Therefore, the laser processing device 10 is used for laser processing based on various information such as a device used for drilling (laser oscillation device 1, transmission optical system 2, etc.), a drilling position by a pulse laser, and a measuring ability of the power meter 5. An appropriate pulse irradiation pattern is determined.

  By the way, it is desirable that the pulse energy on the workpiece irradiation surface is stable, but in reality, it may slightly change depending on the frequency. In particular, when the transmission optical system 2 has an optical system that shapes the spatial distribution shape such as the mask 3, the pulse energy on the workpiece irradiation surface is likely to be subject to many output changes due to the frequency. As described above, when the workpiece 4 is processed by the pulse laser, the time response of the frequency characteristic may change variously. For this reason, pulse energy may change due to a difference in time response of frequency characteristics.

  Here, a phenomenon in which the pulse energy changes due to a difference in frequency (change in pulse energy output caused by a difference in time response) will be described. 2-5 is a figure for demonstrating the phenomenon in which pulse energy changes with frequency.

As shown in FIG. 2, the beam pointing (directing direction) of the laser light output from the laser oscillation device 1 may change. In this case, if the frequency is low, the pulse laser passes through the approximate center of the mask 3, whereas if the frequency is high, the pulse laser passes through a position shifted from the center of the mask 3. When the pulse laser passes through a position shifted from the center of the mask 3, the amount of light of the pulse laser passing through the mask 3 is smaller than when the pulse laser passes through the approximate center of the mask 3. For this reason, when the mask 3 is used and the high-frequency pulse laser is irradiated, the pulse energy on the workpiece irradiation surface becomes lower than that at the low frequency (the irradiation energy on the workpiece irradiation surface is reduced in output). To do).

  Further, as shown in FIG. 3, the beam mode shape (mode order) output from the laser oscillation device 1 may change. In this case, the pulse energy on the workpiece irradiation surface is lower at the high frequency than at the low frequency.

  As shown in FIG. 4, the beam diameter of the pulse laser output from the laser oscillation device 1 may change, or the beam diameter of the pulse laser may change in the transmission optical system 2. In the case of FIG. 4, when the frequency is high, the pulse energy on the workpiece irradiation surface becomes higher (output increases) than when the frequency is low.

  Further, as shown in FIG. 5, the beam mode shape may change in the transmission optical system 2. For example, when a beam shaped into a top hat type is used, the profile shape of the beam may collapse from the top hat type due to the high frequency of the pulse laser. In this case, the pulse energy on the workpiece irradiation surface is lower at the high frequency than at the low frequency.

  FIG. 6 is a diagram for explaining a difference in time response of frequency characteristics. A characteristic X1 in FIG. 6 is a characteristic in an ideal apparatus having no frequency characteristic, and shows a case where the pulse energy (output) on the workpiece irradiation surface does not change with time.

  Characteristic X2 is a characteristic when pulse laser processing is performed at a high frequency, and shows a case where the temporal change of pulse energy on the workpiece irradiation surface is extremely fast and stable as it is. The characteristic X2 is, for example, a characteristic when the laser oscillation device 1 is a three-axis orthogonal CO2 laser oscillator and is affected by a pre-pulse discharge.

  A characteristic X3 is a characteristic when pulse laser processing is performed at a high frequency, and shows a case where the time change of the pulse energy on the workpiece irradiation surface is relatively fast and is stable after a predetermined time. The characteristic X3 is a characteristic when an axial movement or the like occurs due to, for example, thermal distortion of the optical resonator.

  A characteristic X4 is a characteristic when pulse laser processing is performed at a high frequency, and shows a case where the time change of the pulse energy on the workpiece irradiation surface is relatively gradual and stable after a predetermined time. The characteristic X4 is, for example, a characteristic when receiving an influence of a thermal lens of an optical component.

  As described above, since the cause of the output change due to the frequency exists in the laser oscillation device 1 and the transmission optical system 2, the laser processing device 10 of the present embodiment measures the average output power P on the workpiece irradiation surface (transmission). This is performed after the optical system 2.

As described with reference to FIG. 6, when the workpiece 4 is processed by the pulse laser, the time response of the frequency characteristics may change variously. For example , when laser processing is performed by burst shot, the first pulse laser is irradiated with a pulse energy output that is not affected by the frequency. However, the second and subsequent pulse lasers are irradiated with a pulse energy output affected by the frequency of the pulse laser.

  FIG. 7 is a diagram illustrating an example of a pulse irradiation pattern of a pulse laser irradiated by the laser processing apparatus. FIG. 7 shows an average pulse irradiation pattern simulating actual machining, not a pulse irradiation pattern in actual machining. Although the burst frequency is determined by the processing conditions, the galvano frequency varies depending on the actual hole position, and in this embodiment, the average frequency used is used as a pulse irradiation pattern at the time of energy irradiation. Note that actual processing is not performed by the pulse irradiation pattern shown in FIG. The laser processing apparatus 10 performs a plurality of holes in the workpiece 4 by burst processing. Burst processing is a processing method that repeats the process of irradiating a single processing hole with a plurality of shot pulse lasers, and then moving to the next processing hole and irradiating with a plurality of shot pulse lasers. FIG. 7 shows a pulse irradiation pattern at the time of burst processing, and shows a case where the number of shots to one hole at the time of burst processing (hereinafter referred to as burst shot number Np) is 3 shots.

  The number of sets of pulse groups (3 shots) irradiated to one hole of the workpiece 4 while a predetermined number of holes are drilled in the workpiece 4 is the pulse group number Ng (number of holes). The total number of shots irradiated to the workpiece 4 before the pause time Toff is a value obtained by multiplying the number of pulse groups Ng by the number of burst shots Np.

The frequency in the irradiation time for one shot of the pulse laser irradiated by the laser processing apparatus 10 during burst processing is the burst frequency Fp. Moreover, the average value of the pulse laser which the laser processing apparatus 10 irradiates with respect to one processing hole is the average frequency (galvano frequency) Fg for every hole. The average frequency Fg for each hole is the time (per hole per hole), which is the sum of the time for irradiating the pulse laser to one processing hole and the time for moving to the next processing hole (time for operating the galvano scanner and galvano mirror). The frequency of the pulsed laser at the processing time).

  The average positioning frequency Fm_ave is a frequency when positioning the irradiation position to the processing hole, and is an average value of the number of times positioning can be performed per unit time by a galvano scanner or a galvano mirror. The average positioning frequency Fm_ave may be an average frequency in actual machining or a frequency calculated by another method. In the present embodiment, the average positioning frequency Fm_ave is half of the maximum positioning frequency Fm_max described later. The maximum positioning frequency Fm_max is a frequency when the irradiation position to the processing hole is positioned, and is the maximum value of the number of times positioning can be performed per unit time by a galvano scanner or a galvano mirror.

  The laser processing device 10 pauses the laser oscillation device 1 at a predetermined timing for a predetermined time (rest time Toff) as necessary so that the power meter 5 can stably measure the average output power P. When the laser oscillation device 1 needs to be stopped, the laser oscillation device 1 stops the oscillation of the pulse laser for the pause time Toff after performing a predetermined number of holes in the workpiece 4.

A frequency at a time obtained by combining a predetermined number of drilling times (beam on time Ton) to the workpiece 4 and the pause time Toff is a pulse average frequency <f>. In other words, the pulse irradiation pattern (pulse average frequency <f>) has a frequency (burst frequency Fp) in the irradiation time of one hole portion of the burst processing, the average of each hole assumes a speed associated with the position movement of the irradiation a frequency Fg, the average value of the pulse frequency determined the pause time Toff for protecting the power meter 5 by. In the present embodiment, the average output power P is measured by repeatedly irradiating the power meter 5 with this pulse irradiation pattern as one pattern.

The calculation unit 7 calculates an average pulse energy E per shot when the average pulse irradiation frequency (number of pulse irradiations per unit time) is set to the pulse average frequency <f> by the equation (1). P in the equation (1) is an average output power P measured by the power meter 5.
E = P / <f> (1)

  Thereby, the average pulse energy E in a pulse irradiation pattern can be measured easily. The laser processing apparatus 10 performs laser processing on the workpiece 4 by repeating laser processing at the pulse average frequency <f>. In the present embodiment, the calculation unit 7 of the laser processing apparatus 10 calculates a pulse average frequency <f> optimum for energy measurement based on the processing conditions of the workpiece 4.

  Next, an operation procedure of the laser processing apparatus according to Embodiment 1 will be described. 8 and 9 are flowcharts showing the operation procedure of the laser processing apparatus according to the first embodiment. FIG. 8 and FIG. 9 show the calculation processing procedure of the pulse average frequency <f> and the measurement processing procedure of the average pulse energy E based on the processing conditions input to the laser processing apparatus 10.

  When calculating the pulse average frequency <f>, machining conditions are input to the control device 6 via the I / F unit 8 (step S10). This processing condition may be input by an operator or may be received from another device. Processing conditions include, for example, laser oscillation conditions (pulse width Wd, current value Ip, etc.) that depend on input power, processing reference energy (pulse energy that is a reference per shot) Est, burst to one hole during burst processing The number of shots Np, the burst frequency Fp during burst processing, and the like. In the present embodiment, an example in which the processing conditions are a pulse width Wd = 10 μs, a processing reference energy Est = 10 mJ, a burst shot number Np = 3 shots, and a burst frequency Fp = 10000 Hz will be described.

After the machining conditions are input to the control device 6, the calculation unit 7 calculates the maximum average frequency Fmax_1 of the laser oscillation device 1 using the machining conditions (step S20). The maximum average frequency Fmax_1 of the laser oscillation device 1 is the maximum average frequency at which the laser oscillation device 1 can oscillate. For example, the maximum average frequency Fmax_1 is 3000 Hz. The maximum average frequency Fmax_1 is obtained from the maximum input power of the laser oscillation device 1, the power input to one shot (such as the pulse width Wd and the current value Ip), the load on the optical component, and the like. Since the frequency that can be oscillated by the laser oscillation device 1 is different for each processing, the maximum average frequency Fmax_1 is the maximum value among the averaged frequencies that can be oscillated by the laser oscillation device 1 for each processing.

  Thereafter, the calculation unit 7 performs the first processing condition determination based on the input processing conditions based on the capability of the laser oscillation device 1 (maximum average frequency Fmax_1 of the laser oscillation device 1), the capability of the laser processing device 10, and the like. It is determined whether or not the laser processing apparatus 10 is operable (whether or not the processing conditions are appropriate) (step S30).

  When the laser processing apparatus 10 cannot operate with the input processing conditions (step S30, NG), the calculation unit 7 rejects the input processing conditions (step S40). Specifically, when a processing condition that exceeds the performance of the laser processing apparatus 10 or a processing condition that exceeds the performance of the laser oscillation apparatus 1 is input, the processing unit 7 rejects the input processing condition. As a result, the control device 6 notifies the operator from the I / F unit 8 that the laser processing device 10 cannot operate under the input processing conditions. Thereafter, the machining conditions are re-input to the control device 6 (step S10). The laser processing apparatus 10 repeats the processes of steps S10 to S30 until the calculation unit 7 determines that the laser processing apparatus 10 can operate under the input processing conditions.

  When the laser processing apparatus 10 can operate under the input processing conditions (step S30, OK), the calculation unit 7 uses the average positioning frequency Fm_ave, burst frequency Fp, pulse width Wd, and burst shot number Np for each hole. An average frequency Fg is calculated (step S50). As described above, the average positioning frequency Fm_ave is, for example, half of the maximum positioning frequency Fm_max.

When the maximum positioning frequency Fm_max is Fm_max = 2000 Hz, Fm_ave = 2000 Hz / 2 = 1000 Hz. The calculating part 7 calculates the average frequency Fg for every hole using Formula (2).
Fg = 1 / {(Np−1) / Fp + Wd + (1 / Fm_ave)} (2)
Using this equation (2), the average frequency Fg for each hole is Fg = 1 / {(3-1) /10000+0.00001+ (1/1000)} = 826 Hz.

  Next, the computing unit 7 calculates the maximum average frequency Fmax_2 when the laser oscillation device 1 repeats the oscillation of the pulse group (step S60). Specifically, the maximum average frequency Fmax_2 is Fmax_2 = Fg × Np = 2478 Hz.

  Moreover, the calculating part 7 calculates the maximum average frequency Fmax_3 which can be accept | permitted by the power range set to the laser processing apparatus 10 (step S70). This maximum average frequency Fmax_3 is calculated using the upper limit output PWR_max of the power range and the machining reference energy Est. When the upper limit output PWR_max (maximum output) of the power range is 3 W, Fmax_3 = PWR_max / Est = 3 / 0.01 = 300 Hz. Note that either step S60 or step S70 may be performed first.

  Thereafter, the calculation unit 7 calculates a pulse average frequency Fmax_min (step S80). The calculation process of the pulse average frequency Fmax_min in step S80 is the first calculation process c1 of the pulse average frequency. The pulse average frequency Fmax_min is an average frequency of the pulse laser allowed in the laser processing apparatus 10. The calculation unit 7 compares the maximum average frequencies Fmax_1, Fmax_2, and Fmax_3 and sets the minimum one as the pulse average frequency Fmax_min. This is because the maximum average frequencies Fmax_1, Fmax_2, and Fmax_3 are frequencies at the capacity limit, respectively, and in order to be used below the capacity limit, it is necessary that the frequencies be all the maximum average frequencies Fmax_1, Fmax_2, and Fmax_3. It is. In the example of the present embodiment, Fmax_min = Fmax_3 = 300 Hz.

  Next, the computing unit 7 calculates the number of pulse groups Ng (step S90). In the example of the present embodiment, the number of pulse groups Ng is Ng = Fmax_min / Np = 300/3 = 100 groups.

  When the pulse average frequency Fmax_min is not divisible by the burst shot number Np, the calculation unit 7 performs fine correction of the pulse average frequency Fmax_min to calculate the pulse average frequency Fx after fine correction (step S100). The calculation process of the pulse average frequency Fx in step S100 is a second calculation process c2 of the pulse average frequency. Specifically, the calculation unit 7 rounds down the value after the decimal point of the calculated pulse group number Ng to make the pulse group number Ng a natural number. Then, a value obtained by multiplying the natural number of the pulse group number Ng and the burst shot number Np is set as the finely corrected pulse average frequency Fx. In the example of the present embodiment, Fx = Ng × Np = 100 × 3 = 300 Hz, which is the same as the pulse average frequency Fmax_min before fine correction, and therefore the processing in step S100 may be omitted.

  In the following processing, the calculation unit 7 performs different processing depending on whether the pulse average frequency Fmax_min is Fmax_1, Fmax_2, or Fmax_3. For this reason, the calculating part 7 confirms which of Fmax_1, Fmax_2, and Fmax_3 is selected as the pulse average frequency Fmax_min (step S110).

  When Fmax_1 or Fmax_3 is selected as the pulse average frequency Fmax_min (step S110, Fmax_1 or Fmax_3), the calculation unit 7 puts the average frequency of the pulse laser oscillated by the laser oscillation device 1 into the measurement capability range of the power meter 5, A pause time Toff is set (step S120). In the example of the present embodiment, since Fmax_min = Fmax_3, the calculation unit 7 sets the pause time Toff. It has been found that if the pause time Toff is too long, the measurement accuracy of the power meter 5 deteriorates. Although it is possible to optimize the pause time Toff from various viewpoints, in the present embodiment, a case where the pause time Toff is a fixed value of Toff = 0.15 s will be described.

  The calculator 7 calculates the beam on time Ton (step S130). In the example of the present embodiment, Ton = Ng / Fg = 100/826 = 0.121 s. Thereafter, the calculation unit 7 determines the beam on time Ton (step S140). Specifically, the calculation unit 7 determines whether or not the beam on time Ton is shorter than the maximum beam on time Ton_max. The maximum beam-on time Ton_max is an allowable beam-on time, and the laser processing apparatus 10 is allowed to irradiate a pulse laser for a time shorter than the maximum beam-on time Ton_max.

  When the beam on time Ton is equal to or longer than the maximum beam on time Ton_max (step S140, NG), the calculation unit 7 recalculates the pulse average frequency Fx (step S150). The calculation process of the pulse average frequency Fx in step S150 is a third calculation process c3 of the pulse average frequency. When the beam on time Ton is equal to or longer than the maximum beam on time Ton_max, the calculation unit 7 fixes the beam on time Ton at Ton_max, and calculates the pulse average frequency <f> (step S160). Thus, when the pause time Toff is set, the pulse average frequency <f> determined by the beam on time Ton and the pause time Toff may be defined based on the capability of the power meter 5.

  When the beam on time Ton is shorter than the maximum beam on time Ton_max (step S140, OK), the calculation unit 7 determines the pulse average frequency <f> to be <f> = Fx (step S160). For example, the maximum beam on time Ton_max is set to Ton_max = 0.15 s. In this case, since the beam on time Ton is smaller than the maximum beam on time Ton_max, the pulse average frequency <f> is <f> = Fx = 300 Hz. In other words, in the example of the present embodiment, since the beam on time Ton is within the range of the maximum beam on time Ton_max, the pulse average frequency is determined as <f> = Fx = 300 Hz.

  When Fmax_2 is selected as the pulse average frequency Fmax_min (step S110, Fmax_2), irradiation is performed with an ideal pulse group irradiation pattern. Therefore, the calculation unit 7 determines that the setting of the pause time Toff is unnecessary, and determines the pulse average frequency <f> as <f> = Fx without setting the pause time Toff (step S160).

  After the irradiation pattern condition (pulse average frequency <f>) is determined, the power meter 5 starts measuring the average output power (actual power) P. First, the power meter 5 is moved onto the work table 9 and fixed at the irradiation position of the pulse laser. Then, the laser oscillation device 1 oscillates a pulse laser and irradiates the power meter 5 through the transmission optical system 2. Thereby, the power meter 5 measures the average output power P of the pulse laser (step S170). The average output power P measured by the power meter 5 is sent to the calculation unit 7.

  The computing unit 7 determines whether the power range (actual power range) of the average output power P is within a predetermined range (step S180). Specifically, it is determined whether or not the average output power P is within the range from the power range lower limit output PWR_min to the power range upper limit output PWR_max. In other words, the calculation unit 7 determines whether or not the pulse laser oscillated by the laser oscillation device 1 is a pulse laser that is equal to or higher than the measurement capability of the power meter 5.

  If the average output power P (measured value) is outside the power range range (step S180, NG), the calculation unit 7 sends the determination result to the control device 6. As a result, the control device 6 causes the laser oscillation device 1 to stop the beam output (step S190), and performs an alarm display (a1) from the I / F unit 8 or the like (step S200). The alarm display (a1) is a message indicating that the average output power P is out of the power range.

  If the average output power P is within the power range range (step S180, OK), the computing unit 7 calculates the pulse average energy E by E = P / <f> (step S210). And the calculating part 7 determines whether the pulse average energy E is in a regulation range as energy determination (step S220).

  For example, if the pulse average energy E is not within the required accuracy range of pulse average energy (within the machining reference energy Est ± x%) (step S220, NG), for example, the calculation unit 7 determines that the pulse average energy E Is outside the specified range, and the determination result is notified to the control device 6.

  When the pulse average energy E is outside the specified range, the calculation unit 7 counts the number of adjustments of the pulse laser output adjusted by the control device 6 (step S230), and the number of adjustments thus counted is the maximum number of adjustments set in advance. It is determined whether it is within the range (step S240).

  If the counted number of adjustments is within the range of the maximum number of adjustments set in advance (within the allowable range of the number of adjustments) (step S240, OK), the controller 6 is informed that the pulse average energy E is outside the specified range. Notice. Accordingly, the control device 6 controls the laser oscillation device 1 and the transmission optical system 2 to adjust the output of the pulse laser (step S250). Then, the laser processing apparatus 10 returns to the process of step S170, and performs the process after step S170.

  If the counted number of adjustments exceeds the preset maximum number of adjustments (step S240, NG), the controller 6 is notified that the counted number of adjustments exceeds the maximum number of adjustments. As a result, the control device 6 causes the laser oscillation device 1 to stop the beam output (step S260), and performs an alarm display (a2) from the I / F unit 8 or the like (step S270). The alarm display (a2) is a message indicating that the pulse average energy E is out of the specified range, and that the number of adjustments of the pulse laser output exceeds the maximum number of adjustments.

  At the time of energy determination (step S220), the calculation unit 7 determines that, for example, if the pulse average energy E is within a predetermined processing reference energy Est ± x% (step S220, OK), the pulse average energy E Is within the specified range, and the determination result is notified to the control device 6. Thereby, the control apparatus 6 completes the measurement of the pulse average energy E (step S280). Thereafter, the control device 6 uses the laser irradiation device 1 and the transmission optical system 2 based on the pulse irradiation pattern (pulse average irradiation number <f>) obtained by using the pulse energy measurement method of the present embodiment described above. To control.

  As described above, when processing conditions are input from the I / F unit 8, an appropriate pulse irradiation pattern (pulse average frequency <f>) is automatically set in consideration of the capabilities of the laser oscillation device 1 and the power meter 5. The Since an appropriate pulse irradiation pattern is set in the presence of an arbitrary pulse irradiation pattern, an appropriate average output power P can be measured. Furthermore, since the accurate pulse average energy E is calculated from E = P / <f>, laser processing based on the appropriate pulse average energy E can be performed. Thereby, it becomes possible to improve the machining quality of the entire workpiece 4.

  Even if there is a machine difference in the frequency characteristics, the laser machining is performed based on the calculated appropriate pulse average energy E, so that the machining quality difference of the entire workpiece 4 can be reduced. In addition, since the average output power P is not measured beyond the measurement capability of the power meter 5, it is possible to prevent the laser light receiving unit (power measurement light receiving unit) of the power meter 5 from being damaged.

  In addition, since the average output power P of the average frequency simulating actual machining is measured on the workpiece irradiation surface, the frequency effect of the pulse output generated in the laser oscillation device 1 and the thermal effect received in the transmission optical system 2 are also measured. It is possible to measure an accurate average output power P taking into account. Further, when the transmission optical system 2 has the mask 3 for shaping the beam mode shape, the pulse energy on the workpiece irradiation surface also affects the change of the beam pointing generated in the laser oscillation device 1. receive. Also in this case, it is possible to measure the accurate average output power P by measuring the average output power P on the workpiece irradiation surface.

  As described above, according to the first embodiment, the measurement of the average output power P of the pulse laser is performed in a pattern close to the average irradiation pattern at the time of machining, so that the machining quality of the entire workpiece can be improved. . In addition, since the average output power P of the pulse laser is not measured with a measurement capability higher than that of the power meter 5, it is possible to prevent the power meter 5 from being damaged. Moreover, since the pulse average energy E is calculated based on the measurement capability of the power meter 5, it is possible to calculate the accurate pulse average energy E, and the output adjustment of the pulse laser based on the pulse average energy E can be adjusted. It becomes possible to carry out appropriately. Therefore, it is possible to perform laser processing with stable processing quality at low cost while preventing the power meter 5 from being damaged.

Embodiment 2. FIG.
Next, a laser processing apparatus according to Embodiment 2 will be described with reference to FIGS. In the second embodiment, the power range of the power meter 5 is configured to be switchable in a plurality of stages. For example, when measuring a low average output power P, it is measured in a low power range, and when measuring a high average output power P, it is measured in a high power range. Further, the power range may be automatically set based on the processing conditions input from the I / F unit 8. In addition, since the laser processing apparatus 10 which concerns on Embodiment 2 has the structure similar to the laser processing apparatus 10 which concerns on Embodiment 1, the description is abbreviate | omitted.

  Hereinafter, an operation procedure of the laser processing apparatus 10 according to the second embodiment will be described. 10 and 11 are flowcharts showing the operation procedure of the laser processing apparatus according to the second embodiment. FIG. 10 and FIG. 11 show the calculation processing procedure of the pulse average frequency <f> and the measurement processing procedure of the average pulse energy E based on the processing conditions input to the laser processing apparatus 10. In addition, the description about the procedure which performs the process similar to the laser processing apparatus 10 of Embodiment 1 may be abbreviate | omitted.

  The laser processing apparatus 10 performs the processes of steps S310 to S360 as the same processes as steps S10 to S60 of the first embodiment. That is, when calculating the pulse average frequency <f>, the machining conditions are input to the control device 6 via the I / F unit 8 (step S310). In the present embodiment, an example in which the processing conditions are a pulse width Wd = 10 μs, a processing reference energy Est = 10 mJ, a burst shot number Np = 3 shots, and a burst frequency Fp = 10000 Hz will be described.

  After the machining conditions are input to the control device 6, the calculation unit 7 calculates the maximum average frequency Fmax_1 of the laser oscillation device 1 using the machining conditions (step S320). For example, the maximum average frequency Fmax_1 = 3000 Hz.

  Thereafter, the calculation unit 7 determines whether or not the laser processing apparatus 10 can operate under the input processing conditions based on the capabilities of the laser oscillation device 1 and the optical transmission system 2 as the first processing condition determination. Determination is made (step S330).

  When the laser processing apparatus 10 cannot operate under the input processing conditions (step S330, NG), the calculation unit 7 rejects the input processing conditions (step S340). As a result, the control device 6 notifies the operator from the I / F unit 8 that the laser processing device 10 cannot operate under the input processing conditions. Thereafter, the machining conditions are re-input to the control device 6 (step S310). The laser processing apparatus 10 repeats the processes of steps S310 to S330 until the calculation unit 7 determines that the laser processing apparatus 10 is operable under the input processing conditions.

  When the laser processing apparatus 10 can operate under the input processing conditions (step S330, OK), the calculation unit 7 uses the average positioning frequency Fm_ave, burst frequency Fp, pulse width Wd, and burst shot number Np for each hole. An average frequency Fg is calculated (step S350). As described above, the average positioning frequency Fm_ave is, for example, half of the maximum positioning frequency Fm_max.

  When the maximum positioning frequency Fm_max is Fm_max = 2000 Hz, Fm_ave = 2000 Hz / 2 = 1000 Hz. The calculation unit 7 calculates the average frequency Fg for each hole using the equation (2) described in the first embodiment. When Expression (2) is used, Fg = 826 Hz as in the first embodiment.

  Next, the computing unit 7 calculates the maximum average frequency Fmax_2 when the laser oscillation device 1 repeats the oscillation of the pulse group (step S360). Specifically, the maximum average frequency Fmax_2 is Fmax_2 = Fg × Np = 2478 Hz.

  The computing unit 7 predicts the expected average output power PW_2 by calculating the average power output of the pulse laser irradiated onto the workpiece irradiation surface (step S370). In the example of the present embodiment, the expected average output power PW_2 is PW_2 = Est × Fmax_2 = 0.01 × 2478 = 24.8W.

  In the present embodiment, the following four power ranges are set in the power meter 5. The power ranges set in the power meter 5 are (1) power range R1: 0 to 1 W, (2) power range R2: 1 to 3 W, (3) power range R3: 3 to 5 W, and (4) power range R4: 5-10W.

  The calculation unit 7 temporarily sets, as the power range PW_max (1), a power range in which the expected average output power PW_2 is included in the power range set in the power meter 5 or a power range close to the expected average output power PW_2. (Step S380). In the example of the present embodiment, (4) power range R4: a power range larger than the power range of 5 to 10 W is required, but a power range larger than power range R4 is not set in power meter 5. The power range R4 is applied to the power meter 5, and (4) PW_max = 10W is set.

The computing unit 7 calculates a maximum average frequency Fmax_3 (n) (n is any one of R1 to R4) that is allowable in the power range set in the laser processing apparatus 10 (step S390).
The maximum average frequency Fmax_3 (n) is calculated using the upper limit output PWR_max (10W) of the power range R4 and the machining reference energy Est. Since the maximum output of the power range is 10 W, the maximum average frequency Fmax_3 (R4) is Fmax_3 (R4) = PWR_max / Est = 10 / 0.01 = 1000 Hz.

  Thereafter, the calculation unit 7 calculates a pulse average frequency Fmax_min (step S400). The calculation process of the pulse average frequency Fmax_min in step S400 is the first calculation process c11 of the pulse average frequency. The calculation unit 7 compares the maximum average frequencies Fmax_1, Fmax_2, and Fmax_3 (n) and sets the minimum one as the pulse average frequency Fmax_min. In the example of the present embodiment, Fmax_min = Fmax_3 (4R) = 1000 Hz.

  Next, the computing unit 7 calculates the number of pulse groups Ng (step S410). In the example of the present embodiment, the pulse group number Ng is Ng = Fmax_min / Np = 1000/3 = 333.3 group.

  When the pulse average frequency Fmax_min is not divisible by the burst shot number Np, the arithmetic unit 7 performs fine correction of the pulse average frequency Fmax_min to calculate the pulse average frequency Fx (n) after fine correction (step S420). . The calculation process of the pulse average frequency Fx in step S420 is a second calculation process c12 of the pulse average frequency. Specifically, the calculation unit 7 rounds down the value after the decimal point of the calculated pulse group number Ng to make the pulse group number Ng a natural number. In the example of the present embodiment, the number of pulse groups Ng = 333. Then, a value obtained by multiplying the natural number of the pulse group number Ng and the burst shot number Np is set as the finely corrected pulse average frequency Fx. In the example of the present embodiment, Fx = Ng × Np = 333 × 3 = 999 Hz. If the pulse average frequency Fmax_min before the fine correction is the same as the pulse average frequency Fx after the fine correction (when the pulse average frequency Fmax_min is divisible by the burst shot number Np), the process of step S420 may be omitted. .

  In the following processing, the calculation unit 7 performs different processing depending on whether the pulse average frequency Fmax_min is Fmax_1, Fmax_2, or Fmax_3. This is because whether or not the pause time Toff needs to be set and whether or not the power range needs to be changed depends on which pulse average frequency Fmax_min is.

  For example, if the maximum average frequency Fmax_1 is selected, the power range may be switched because the frequency of the pulse laser is output from the laser oscillation device 1, and at a frequency lower than the power range of the maximum average frequency Fmax_2. Since there is, it can be determined that it is necessary to include the pause time Toff.

  If the maximum average frequency Fmax_2 is selected, there is no problem of the power range because the frequency of the pulse laser is a value derived from the ideal pulse group irradiation pattern, and it is not necessary to set the pause time Toff. It can be judged.

  If the maximum average frequency Fmax_3 (n) is selected, it may be considered that there is no problem in the power range. However, since the frequency is lower than the power range of the maximum average frequency Fmax_2, it is necessary to include the pause time Toff. It can be judged that there is.

  Therefore, the calculation unit 7 confirms which of Fmax_1, Fmax_2, and Fmax_3 is selected as the pulse average frequency Fmax_min (step S430). When Fmax_1 is selected as the pulse average frequency Fmax_min (step S430, Fmax_1), the calculation unit 7 calculates the expected average output power PW_n (step S440). And the calculating part 7 determines a power range anew by comparing the estimated average output power PW_n with the power range currently set (step S450). The calculation unit 7 determines whether or not the average output power P is within the range from the power range lower limit output PWR_min to the power range upper limit output PWR_max. For example, when the difference or ratio between the expected average output power PW_n and the currently set power range is greater than or equal to a predetermined value, the calculation unit 7 may determine that the currently set power range is inappropriate. .

  If the currently set power range is inappropriate (step S450, NG), the calculation unit 7 determines whether or not the currently set power range can be switched to a new power range (step S460). In other words, the calculation unit 7 determines whether another power range is more appropriate than the currently set power range. When it is possible to switch from the currently set power range to a new power range (step S460, OK), the computing unit 7 changes the power range to an appropriate power range (step S470). Then, the laser processing apparatus 10 returns to the process of step S390, and performs the process after step S390.

  On the other hand, when the currently set power range is appropriate (step S450, OK) or when it is not possible to switch from the currently set power range to a new power range (step S460, NG), the laser processing apparatus 10 The rest time Toff is set without changing the power range of the power meter 5 (step S480).

  When Fmax_3 (n) is selected as the pulse average frequency Fmax_min (step S430, Fmax_3 (n)), the calculation unit 7 measures the average frequency of the pulse laser oscillated by the laser oscillation device 1 with the power meter 5. In order to enter the capability range, a pause time Toff is set (step S480). In the example of the present embodiment, since Fmax_min = Fmax_3 (R4), the calculation unit 7 sets the pause time Toff. It has been found that if the pause time Toff is too long, the measurement accuracy of the power meter 5 deteriorates. Although it is possible to optimize the pause time Toff from various viewpoints, in the present embodiment, a case where the pause time Toff is a fixed value of Toff = 0.15 s will be described.

  The calculator 7 calculates the beam on time Ton (step S490). In the example of the present embodiment, Ton = Ng / Fg = 333/826 = 0.403 s. Thereafter, the calculation unit 7 determines the beam on time Ton (step S500). Specifically, the calculation unit 7 determines whether or not the beam on time Ton is shorter than the maximum beam on time Ton_max.

  When the beam on time Ton is equal to or longer than the maximum beam on time Ton_max (step S500, NG), the calculation unit 7 recalculates the pulse average frequency Fx (n) (step S510). The calculation process of the pulse average frequency Fx (n) in step S510 is a third calculation process c13 of the pulse average frequency. For example, the maximum beam on time Ton_max is set to Ton_max = 0.15 s. In this case, in the example of the present embodiment, since the beam on time Ton is equal to or longer than the maximum beam on time Ton_max, the beam on time Ton is fixed at Ton_max, and the pulse average frequency <f> is calculated. The number of pulse groups Ng2 included in the beam-on time Ton is Ng2 = Ton_max / (1 / Fg) = 0.15 / (1/826) = 123.9. Therefore, when the number of decimal places of the pulse group number Ng2 is rounded down, the pulse group number Ng2 = 123 groups. As a result, the pulse average frequency Fx (R4) after fine correction becomes Ng2 × Np = 123 × 3 = 369 Hz.

  Thereafter, the calculation unit 7 calculates an expected average output power PW_n (step S520). The expected average output power PW_n in the example of the present embodiment is PW_ (R4) = Est × Fx (R4) = 0.01 × 369 = 3.69W. Then, the computing unit 7 determines the power range again by comparing the predicted average output power PW_n with the currently set power range (step S530). The calculation unit 7 determines whether or not the average output power P is within the range from the power range lower limit output PWR_min to the power range upper limit output PWR_max.

  When the currently set power range is inappropriate (step S530, NG), the calculation unit 7 determines whether or not the currently set power range can be switched to a new power range (step S540). In other words, the calculation unit 7 determines whether another power range is more appropriate than the currently set power range. If the power range that is currently set can be switched to a new power range (step S540, OK), the computing unit 7 changes the power range to an appropriate power range. In the example of the present embodiment, since the expected average output power PW_n is 3.69 W, the power range R2 (3 to 5 W) is preferable to the power range R4. Therefore, the laser processing apparatus 10 changes the power range of the power meter 5 from 10 W to 5 W (step S550), and determines the pulse average frequency <f> (step S560).

  On the other hand, when the currently set power range is appropriate (step S530, OK) or when it is not possible to switch from the currently set power range to a new power range (step S540, NG), the laser processing apparatus 10 The pulse average frequency <f> is determined without changing the power range of the power meter 5 (step S560).

  When the beam on time Ton is shorter than the maximum beam on time Ton_max (step S500, OK), the calculation unit 7 determines the pulse average frequency <f> without changing the power range (step S560).

  When Fmax_2 is selected as the pulse average frequency Fmax_min (step S430, Fmax_2), irradiation is performed with an ideal pulse group irradiation pattern. Therefore, the calculation unit 7 determines that it is not necessary to change the power range or set the pause time Toff. Therefore, the calculation unit 7 determines the pulse average frequency <f> without changing the power range or setting the pause time (step S560).

  In the example of the present embodiment, since Fmax_min = Fmax_3 (R4), the pulse average frequency <f> is determined as <f> = Fx (R4) = 369 Hz. After the pulse average frequency <f> is determined, the power meter 5 starts measuring the average output power P. Thereafter, the laser processing apparatus 10 measures the pulse average energy E by the same process as the laser processing apparatus 10 of the first embodiment, and the description thereof is omitted. Note that the processing in steps S570 to S680 shown in FIG. 11 corresponds to the processing in steps S170 to S280 shown in FIG. Thereafter, the control device 6 controls the laser oscillation device 1 and the transmission optical system 2 based on the pulse average energy E obtained by using the pulse energy measurement method of the present embodiment described above.

  As described above, according to the second embodiment, it is possible to calculate the accurate pulse average energy E while switching the power range to an appropriate power range, and to adjust the output of the pulse laser based on the pulse average energy E. It becomes possible to carry out appropriately. Therefore, laser processing with stable processing quality can be performed at low cost.

  As described above, the laser processing apparatus according to the present invention is suitable for laser processing of a workpiece using a pulse laser.

Claims (5)

A laser oscillation device that outputs a pulse laser; and
A transmission optical system for transmitting the pulse laser output from the laser oscillation device to a laser light irradiation surface of a workpiece;
A power measuring device for measuring the laser power of the pulse laser;
Each pulse to the power measuring device and the work is irradiated so that the pulse laser is applied to the power measuring device and the work within the oscillation capacity range of the laser oscillating device and within the power measuring capability range of the power measuring device. An operation unit that calculates an irradiation pattern based on laser processing conditions of the workpiece,
When the laser oscillation device is controlled according to the pulse irradiation pattern and the pulse energy of the pulse laser per shot calculated using the laser power measured by the power measurement device is within a predetermined range set in advance. A control device for performing laser processing of the workpiece;
With
The computing unit is
Number of pulse irradiations per unit time in a combined time of a beam-on time, which is a predetermined number of drilling times for the workpiece, and a pause time, which is a time for stopping laser oscillation for a predetermined time after the predetermined number of holes are drilled As the maximum value of the average frequency is
A first maximum average frequency at which the laser oscillation device can oscillate;
A second maximum average frequency when the pause time is assumed to be zero in pulse irradiation by the laser oscillation device;
A third maximum average frequency allowable in the power range set in the power measuring device;
And calculating the pulse irradiation pattern using the smallest maximum average frequency among the first to third maximum average frequencies.   The laser processing apparatus according to claim 1, wherein the power measuring apparatus measures a laser power of the pulse laser at a position when laser processing is performed on the workpiece. The transmission optical system has a mask for shaping the spatial distribution shape of the pulse laser,
The laser processing apparatus according to claim 1, wherein the pulse laser is irradiated onto the power measuring device and the workpiece after a spatial distribution shape is shaped by the mask.   The said power measurement apparatus is comprised so that a measurement power range can be switched in multiple steps | paragraphs, The said measurement power range is switched based on the magnitude | size of the estimated laser power. Laser processing equipment. The calculation unit calculates the pulse energy per shot by dividing the laser power measured by the power measuring device by the number of pulse irradiations per unit time,
The laser processing apparatus according to claim 1, wherein the control device performs laser processing of the workpiece when the pulse energy calculated by the calculation unit is within a predetermined range set in advance.

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