KR102615048B1 - Laser processing apparatus and power supply apparatus thereof - Google Patents

Abstract

Provides a laser processing machine and its power supply that can more accurately control the intensity or energy of a laser pulse beam.
The power supply device 120 supplies burst-like high-frequency voltage (V _RF ) to the laser oscillator 110. The photodetector 180 detects the pulse laser (Lp) output from the laser oscillator 110 and generates a pulse-like first detection signal Vs1. The laser control device 140 provides an excitation signal (S4) to the power supply device 120 in accordance with the timing signal (S1) to generate a high frequency voltage (V _RF ) and smoothes the first detection signal Vs1 A second detection signal Vs2 is generated, and the state of the power supply device 120 is adjusted based on the second detection signal Vs2.

Description

Laser processing machine and its power supply {LASER PROCESSING APPARATUS AND POWER SUPPLY APPARATUS THEREOF}

This application claims priority based on Japanese Patent Application No. 2018-081677 filed on April 20, 2018. The entire contents of the application are incorporated by reference into this specification.

The present invention relates to a power supply device.

As an industrial processing tool, laser processing machines are widely used. Figure 1 is a block diagram of the laser processing machine 1r. The laser processing machine 1r is equipped with a laser oscillator 2, such as a CO ₂ laser, and a laser drive device 4r that supplies alternating current power to the laser oscillator 2 to excite it. The laser driving device 4r is provided with a direct current power source 6 and a high frequency power source 8. The direct current power supply 6 generates direct current voltage (V _DC ). The high-frequency power source 8 receives direct current voltage (V _DC ), converts it into high-frequency voltage (V _RF ), and supplies it to the laser oscillator 2, which is a load.

In the laser processing machine 1r for drilling, the laser oscillator 2 operates discontinuously. In other words, a relatively short light emission period of a few microseconds to 10 microseconds and an equally long (or short) rest period are alternately repeated, and therefore, a pulse laser (Lp) is generated from the laser oscillator 2. is released.

The intensity of the pulse laser (Lp) can be controlled according to the amplitude of the high frequency voltage (V _RF ), but in reality, it fluctuates under the influence of environmental temperature and deterioration of the laser gas. That is, even if a high frequency voltage (V _RF ) of the same amplitude is applied, the intensity of the obtained pulse laser (Lp) changes from moment to moment. Fluctuations in the intensity of the pulse laser cause a decrease in processing accuracy. Therefore, a technology to stabilize the intensity of pulsed laser (Lp) has been proposed.

Patent Document 1: Japanese Patent Publication No. 2016-59932 Patent Document 2: Japanese Patent Publication No. 2015-223591

FIG. 2 is a diagram showing an example of the waveform of the intensity of the pulse laser Lp. The waveform of the pulse laser Lp is not necessarily uniform during the emission time Te, and typically rises sharply immediately after emission and gradually decreases when emission is stopped. In this specification, the average intensity (average output within the pulse width) during the emission time Te of the pulse laser Lp is referred to as the effective intensity I _eff . The effective intensity (I _eff ) may be determined as the energy per pulse divided by the emission time (Te).

Patent Document 2 discloses a technique for detecting the intensity of a pulse laser (Lp) and feedback controlling the command value of the intensity of the pulse laser so that the deviation between the integral value of the detected value and the integral value of the output target value is reduced. do.

In the technology of Patent Document 2, the total amount of laser energy can be brought close to the target value in a somewhat long integration period (for example, 1 second) including a plurality of pulse lasers. In other words, it does not guarantee that the effective intensity (I _eff ) of each pulse laser is maintained at the target value.

The present invention has been made in this situation, and one of the exemplary purposes of one aspect thereof is to provide a laser processing machine and a power supply device thereof that can more accurately control the intensity or energy of a laser pulse beam.

One aspect of the present invention relates to a laser processing machine. The laser processing machine includes a processing machine control device that generates a pulse-shaped timing signal, a laser oscillator, a power supply device that supplies a burst-shaped high-frequency voltage to the laser oscillator, and detects a pulse laser output from the laser oscillator, and performs a pulse-shaped first detection. According to the photodetection element that generates the signal and the timing signal, an excitation signal is applied to the power supply to generate a high-frequency voltage, and the first detection signal is smoothed to generate a second detection signal based on the second detection signal. A laser control device is provided to control the status of the power supply.

According to this aspect, the effective intensity or energy of each shot of the pulse laser can be accurately controlled.

The laser control device may adjust the amplitude of the high frequency voltage. Thereby, the intensity of the pulse laser can be adjusted.

Instead, or in addition, the laser control device may adjust the generation time of the high-frequency voltage. As a result, the energy of the pulse laser per shot can be adjusted.

The pulse width and/or frequency of the timing signal is variable, the first detection signal is binarized to generate a third detection signal, the third detection signal is smoothed to detect the fourth detection signal, and the second detection signal is converted to the fourth detection signal. The state of the power supply device may be adjusted based on the fifth detection signal obtained by dividing the detection signal. Accordingly, even when the pulse width or frequency of the timing signal varies, the intensity of each pulse laser can be accurately controlled.

Another aspect of the present invention relates to a power supply device that drives a laser oscillator based on a pulse-like timing signal. The power supply device includes a direct current power source that generates a direct current voltage, a high frequency power source that converts the direct current voltage into a high frequency voltage and intermittently supplies the high frequency voltage to the laser oscillator according to a timing signal, and detects the pulse laser output from the laser oscillator. , a photodetection element that generates a pulse-like first detection signal, and a second detection signal is generated by smoothing the first detection signal, and based on the second detection signal, at least one of the DC voltage of the DC power supply and the operating time of the high-frequency power supply. It is equipped with a laser control device that controls one side.

The pulse width and/or frequency of the timing signal may be variable. The laser control device generates a third detection signal by binarizing the first detection signal, detects a fourth detection signal by smoothing the third detection signal, and detects a fifth detection signal obtained by dividing the second detection signal by the fourth detection signal. Feedback control may be performed so that the signal approaches the target value.

The laser control device may update the operating parameters of the direct current power supply and/or the high frequency power supply for each pulse of the timing signal, that is, for each laser shot.

However, any combination of the above components or substitution of the components or expressions of the present invention among methods, devices, systems, etc. are also effective as aspects of the present invention.

According to one aspect of the present invention, the intensity or energy of the laser pulse beam can be controlled more accurately.

Figure 1 is a block diagram of a laser processing machine.
Figure 2 is a diagram showing an example of the waveform of the intensity of the pulse laser (Lp).
Figure 3 is a block diagram showing the configuration of a laser processing machine.
Fig. 4 is a block diagram of a laser device according to the first embodiment.
Figure 5 is an operation waveform diagram of the laser device of Figure 4.
Figure 6 is a block diagram showing a configuration example of a power supply device.
Figure 7 is a block diagram of a laser control device according to the first embodiment.
Figure 8 is a waveform diagram showing an example of a correction operation.
Fig. 9 is a block diagram of a laser control device according to the second embodiment.
Fig. 10 is a block diagram of a laser control device according to the third embodiment.
Fig. 11 is a block diagram of a laser control device according to the fourth embodiment.
Fig. 12 is a block diagram of a laser control device according to the second embodiment.
Figure 13 is a block diagram of a laser device according to a modified example.

Hereinafter, the present invention will be described with reference to the drawings based on appropriate embodiments. Identical or equivalent components, members, and processes appearing in each drawing are given the same reference numerals, and duplicate descriptions are omitted as appropriate. In addition, the embodiment does not limit the invention but is an example, and all features or combinations thereof described in the embodiment are not necessarily essential to the invention.

Figure 3 is a block diagram showing the configuration of a laser processing machine. The laser processing machine 900 processes the object 902 by irradiating the object 902 with a laser pulse beam 904. The type of object 902 is not particularly limited, and the type of processing includes punching (drilling), cutting, etc., but is not limited thereto.

The laser processing machine 900 includes a laser device 100, an optical system 910, a processing machine control device 920, and a stage 930. The object 902 is placed on the stage 930 and fixed as necessary.

The processing machine control device 920 comprehensively controls the laser processing machine 900. Specifically, the processing machine control device 920 outputs a timing signal (S1) and an intensity command (S2) that specifies the intensity of the laser pulse beam to the laser device (100). Additionally, the processing machine control device 920 generates a position control signal (S3) for controlling the stage 930 according to data (recipe) describing the processing.

The stage 930 positions the object 902 according to the position control signal S3 from the processing machine control device 920, and relatively scans the irradiation position of the object 902 and the laser pulse beam 904. do. The stage 930 may be one-axis, two-axis (XY), or three-axis (XYZ).

The laser device 100 oscillates using the timing signal S1 from the processing machine control device 920 as a trigger and generates a laser pulse beam 906. The timing signal S1 is a pulse signal that takes two values: high and low. For example, the high section becomes the light emission section, and the low section becomes the stop section. The intensity during the emission section of the laser pulse beam 906 is set based on the intensity command (S2). The optical system 910 irradiates the object 902 with a laser pulse beam 904. The configuration of the optical system 910 is not particularly limited and may include a mirror group for guiding the beam to the object 902, a lens or aperture for beam forming, etc.

This is the configuration of the laser processing machine 900. Hereinafter, the laser device 100 that operates based on the timing signal S1 and the intensity command S2 from the processing machine control device 920 will be described.

<First embodiment>

Fig. 4 is a block diagram of the laser device 100 according to the first embodiment. The laser device 100 includes a laser oscillator 110, a power supply 120, a laser control device 140, and a photodetector 180.

The laser oscillator 110 includes a pair of discharge electrodes, a pair of mirrors forming a laser resonator, etc.

The power supply device 120 generates a high frequency voltage (V _RF ) and applies it to a pair of discharge electrodes of the laser oscillator 110. The frequency (referred to as synchronous frequency) of the high-frequency voltage (V _RF ) is defined according to the capacitance of a pair of discharge electrodes of the laser oscillator 110 and the resonance frequency of the inductor accompanying it.

The power supply device 120 includes a direct current power supply 200 and a high frequency power supply 300. The direct current power supply 200 generates a direct current voltage (V _DC ). For example, a voltage command (S5) indicating the target level of the direct current voltage (V _DC ) is input to the direct current power supply 200. The voltage command S5 may be an analog reference voltage (V _REF ) representing the target value of the direct current voltage (V _DC ), or may be a digital value representing the reference voltage (V _REF ). The DC power supply 200 stabilizes the voltage level of the DC voltage (V _DC ) to the reference voltage (V _REF ).

The high frequency power source 300 receives direct current voltage (V _DC ) and converts it into alternating current high frequency voltage (V _RF ). The high-frequency power source 300 may include an inverter that converts direct current voltage (V _DC ) into alternating current voltage and a transformer that boosts the output of the inverter. Since the amplitude of the high frequency voltage (V _RF ) is proportional to the direct current voltage (V _DC ), the effective intensity of the pulse laser (Lp) can be controlled based on the voltage command (S5) (reference voltage (V _REF )).

A timing signal (S1) and an intensity command (S2) are input to the laser control device 140. The laser control device 140 supplies an excitation signal S4 of the synchronous frequency to the inverter of the power supply device 120 while the timing signal S1 is high. Accordingly, a burst-like high-frequency voltage (V _RF ) is supplied from the power supply device 120 to the laser oscillator 110, and the laser oscillator 110 alternately repeats oscillation and stopping in accordance with the timing signal S1. Typically, the repetition frequency of the timing signal (S1) is about 1 kHz to 10 kHz, and the pulse width (i.e., the laser excitation time) is on the order of several tens of μs.

The laser control device 140 generates a reference voltage (V _REF ) according to the intensity command (S2). Accordingly, the amplitude of the high frequency voltage (V _RF ) and, by extension, the intensity of the pulse laser (Lp) are controlled according to the intensity command (S2).

The above is the basic configuration of the laser device 100. Next, the basic operation of the laser device 100 will be described. FIG. 5 is an operation waveform diagram of the laser device 100 of FIG. 4. In Figure 5, in order from the top, the timing signal (S1), the excitation signal (S4), the high frequency voltage (V _RF ), the discharge current (I _DIS ) flowing through the discharge electrode of the laser oscillator 110, and the pulse laser (Lp). The intensity appears. However, the vertical and horizontal axes of the waveform diagrams or time charts referred to in this specification are appropriately enlarged or reduced for ease of understanding, and each waveform diagram that appears is simplified, exaggerated, or emphasized for ease of understanding. .

When the timing signal (S1) becomes high at time t ₀ , an excitation signal (S4) having a synchronous frequency is generated. By switching the high frequency power source 300 according to the excitation signal S4, the high frequency voltage V _RF is supplied to the laser oscillator 110. When a high frequency voltage (V _RF ) is applied to the discharge electrode of the laser oscillator 110, discharge occurs, and discharge current (I _DIS ) begins to flow. The excitation signal S4 continues for the on time (excitation time) Ton during which the timing signal S1 becomes high.

At time t ₁ after the start of discharge and a predetermined delay time, the intensity of the pulse laser Lp increases. The waveform of the laser pulse depends on the characteristics of the laser oscillator. In this example, a large peak appears immediately after occurrence, and a flat portion continues thereafter.

When the timing signal S1 becomes low at time t ₂ , the excitation signal S4 stops and the high-frequency voltage V _RF also stops. Then, the discharge gradually weakens and eventually disappears. The intensity of the pulse laser (Lp) also decreases after time _t2 .

The laser device 100 generates a pulse laser (Lp) by repeating this operation.

As described above, even when a high frequency voltage (V _RF ) of a predetermined amplitude is applied, the intensity of the pulse laser (Lp) changes depending on the temperature or deterioration of the gas. Accordingly, the laser control device 140 corrects the state of the power supply device 120 to keep the intensity of the pulse laser (Lp) constant. Returning to FIG. 4, correction of the intensity (or energy) of the pulse laser Lp will be explained.

A portion of the pulse laser (Lp) output from the laser oscillator 110 is branched and input to the photodetector 180 by a beam splitter or the like. The photodetector 180 detects the intensity of the pulse laser Lp and supplies the first detection signal Vs1 to the laser control device 140. The photodetector 180 needs to have a high-speed response capable of detecting the intensity of individual pulses, and therefore it is preferable to use a quantum-type detection element rather than a thermal detection element. The output (first detection signal) Vs1 of the photodetector 180 becomes a pulse-shaped signal according to the waveform of the pulse laser (Lp).

The laser control device 140 stabilizes the intensity (and energy) of the pulse laser Lp based on the first detection signal Vs1 and reduces the effects of temperature and gas deterioration. More specifically, the laser control device 140 includes a smoothing circuit 142 that smoothes the first detection signal Vs1 on the pulse, and based on the smoothed second detection signal Vs2, the state of the power supply device 120 ( Adjust operating parameters). The smoothing circuit 142 can be configured as an analog or digital low-pass filter. The time constant (i.e. cutoff frequency) of the low-pass filter can be determined based on the repetition frequency of the assumed timing signal (S1). For example, the time constant of the low-pass filter is set to about 1 to 20 ms. do. For example, when the frequency of the timing signal S1 is 1 kHz to 10 kHz and the time constant of the low-pass filter is set to 5 ms, the time constant is 5 to 50 times the period of the timing signal S1. The second detection signal Vs2 generated by the smoothing circuit 142 can be understood as representing the average of the effective intensity of several consecutive pulses of the first detection signal Vs1.

When Tp is the repetition period of the timing signal (S1) and Te is the laser emission time (pulse width), their ratio is called the duty ratio (DR).

DR=Te/Tp

The second detection signal Vs2 is proportional to the effective intensity (I _eff ) of the pulse laser multiplied by the duty ratio (DR) of the timing signal (S1). In other words, the detected value of the effective intensity (I _eff ) is expressed by the following equation.

I _eff ∝Vs2/DR

Assuming that the duty ratio (DR) is constant, the second detection signal Vs2 represents the effective intensity (I _eff ).

The laser control device 140 is a correction unit that corrects the operating parameters of the power supply device 120 by feedback control so that the detected value of the effective intensity of the laser obtained based on the second detection signal Vs2 matches the target value. Includes (144). The target value of the effective strength is generated according to the strength command (S2). In this embodiment, the operating parameter to be corrected is the amplitude of the high frequency voltage (V _RF ), that is, the laser control device 140 corrects the direct current voltage (V _DC ).

According to this laser device 100, the effective intensity or energy for each shot of the pulse laser can be accurately controlled by referring to the second detection signal Vs2 smoothed by the smoothing circuit 142. This advantage becomes clear by comparing it with the technology of Patent Document 2.

In Patent Document 2, the energy of the pulse laser is integrated for each shot. If the energy of one shot is normalized to 1, the target value for each shot is 1, 2, 3... is increasing. For example, if the energy (intensity) of 1 pulse at the 100th shot is 1.1, the integrated value fed back is 1000.1, and the target value at this time is 1000. Therefore, even if there is an error of 10% with one short, when viewed as an integrated value, it becomes an error of 0.01%. Therefore, the intensity of the pulse laser is controlled on a long time scale by relatively weak feedback.

In contrast, in this embodiment, the second detection signal Vs2 represents the average of the effective intensity of several consecutive pulses of the first detection signal Vs1. For example, assume it is the average value of 5 pulses. If, among five consecutive pulses, the detection values of four are 1 and the remaining are 1.1, their average will be 1.02, and the error from the target value (1) will be 2%. Therefore, the error is relatively larger than in Patent Document 2, and the intensity of the pulse laser is corrected with strong feedback. Therefore, according to this embodiment, it is possible to control the light intensity more accurately and at higher speed than in Patent Document 2.

FIG. 6 is a block diagram showing a configuration example of the power supply device 120. The DC power supply 200 includes a bank capacitor 202, a charging circuit 210, and a charging controller 230. The direct current power source 200 and the high frequency power source 300 are connected through a DC link 204. A bank capacitor 202 is connected to the DC link 204.

After the laser short circuit ends, the bank capacitor 202 is discharged, and the direct current voltage (V _DC ) decreases. The charging circuit 210 supplies charging current (I _CHG ) to the bank capacitor 202 until the next short circuit, thereby recovering the direct current voltage (V _DC ). The charging controller 230 controls the charging operation by the charging circuit 210 so that the direct current voltage (V _DC ) of the DC link 204 approaches the target voltage (V _REF ) according to the voltage command (S5). . For example, the charging controller 230 may control the charging time and/or charging number of the charging circuit 210 based on the voltage command S5.

The charging circuit 210 can be configured with a switching converter (for example, a step-down DC/DC converter). The charge controller 230 may charge the bank capacitor 202 by the preceding main charge and the subsequent sub-charge.

In main charging, a one-shot pulse having a pulse width according to the voltage command (S5) is generated, the charging circuit 210 is switched once, and charging is performed with approximate precision. As a result, a large charging current is supplied to the bank capacitor 202, and the direct current voltage (V _DC ) recovers to a voltage level approximately close to the reference voltage (V _REF ). Continuing to transition to sub-charging, the DC/DC converter is switched several times so that the direct current voltage (V _DC ) matches the reference voltage (V _REF ).

The high-frequency power source 300 includes a boost transformer 302 and an inverter 310. The secondary winding (W2) of the boosting transformer (302) is connected to the discharge electrode of the laser oscillator (110). The inverter 310 includes, for example, a full bridge circuit. A direct current voltage (V _DC ) is supplied to the power terminal of the inverter 310 . The inverter 310 performs a switching operation according to the excitation signal (S4), applies an alternating current voltage (V _AC ) to the primary winding (W1) of the boost transformer (302), and generates a high-frequency voltage (V) to the secondary winding (W2). _RF ) is generated. However, the configuration and topology of the inverter 310 or the boost transformer 302 are not particularly limited.

<First Example>

Fig. 7 is a block diagram of the laser control device 140A according to the first embodiment. The main part of the laser control device 140A is composed of a digital circuit such as a PLC (Programmable Logic Controller). For simplicity, the repetition frequency and pulse width, or in other words the duty ratio, of the timing signal S1 are assumed to be constant.

The correction unit 144A operates for one cycle of the timing signal S1, that is, for each shot of the pulse laser Lp, and corrects the voltage command S5 (reference voltage V _REF ). In the figure, (n) represents the signal of the nth cycle, and (n-1) represents the signal of the (n-1)th cycle one previous time.

The correction unit 144A includes an A/D converter 150, a subtractor 152, a feedback controller 154, an adder 156, a memory 158, and a D/A converter 160. However, when the correction unit 144A is configured as a PLC, the subtractor 152, feedback controller 154, adder 156, and memory 158 represent functions of a processor executing a software program. The A/D converter 150 converts the analog second detection signal Vs2 into a digital signal DVs2 for each cycle of the timing signal S1, that is, for each laser one shot.

When generating the voltage command (S5) of the nth cycle, the output DVs2 (n-1) of the A/D converter 150 of the immediately preceding cycle (n-1) is referred to. The operation timing of the A/D converter 150 may be immediately after the laser short circuit is completed.

The subtractor 152 generates a difference ΔI(n) between the digital second detection signal DVs2(n-1) and the target value D _REF . The feedback controller 154 generates a correction amount ΔDV so that the difference ΔI approaches zero. In this embodiment, the feedback controller 154 is a P (proportional) controller, and gains multiplies the difference ΔI to generate the correction amount D _CMP (n). However, as the feedback controller 154, a PI (proportional integral) controller or a PID (proportional integral derivative) controller may be used.

The adder 156 adds the correction amount D _CMP (n) to the target value DV _REF (n-1) of the previous cycle and sets it as the target value DV _REF (n) of the next cycle. The D/A converter 160 converts the target value DV _REF (n) into an analog reference voltage V _REF (n). The target value DV _REF (n) is stored in memory 158 and input to adder 156 in the next cycle.

However, the adder 156 may add the correction amount D _CMP (n) to the standard value of the reference voltage V _REF .

Next, the correction operation of the laser device 100 will be described. Figure 8 is a waveform diagram showing an example of a correction operation. Immediately before the emission period of the laser oscillator 110, the direct current voltage (V _DC ) is stabilized at the target voltage (V _REF ). According to the timing signal S1, the laser oscillator 110 oscillates, and a first detection signal Vs1 indicating the intensity of the pulse laser Lp is generated.

The first detection signal Vs1 is smoothed in the laser control device 140, and the second detection signal Vs2 is generated. The second detection signal Vs2 is converted into a digital detection value DVs2 for each cycle. In this example, sampling by the A/D converter is performed immediately after light emission. When the digital detection value DVs2 is acquired, a correction amount (D _CMP ) is generated based on the error ΔI between the digital detection value DVs2 and the target value (D _REF ), and the digital value DV _REF is updated.

For example, as a result of a short circuit in the (n-1) cycle, the digital detection value DVs2(n-1) is lower than the target value (D _REF ). Therefore, a positive correction amount D _CMP (n) is generated, and the reference voltage V _REF (n) in the next n cycle increases. The DC power supply 200 charges the DC voltage (V _DC ) to the new reference voltage V _REF (n) until the next short circuit.

As a result, the amplitude of the high frequency voltage (V _RF ) in the nth cycle becomes larger than the amplitude in the previous (n-1) cycle, and the intensity of the pulse laser Lp in the nth cycle increases. As a result, the second detection signal Vs2 also increases. In this example, since DVs2(n) is higher than the target value (D _REF ), it is fed back so that the reference voltage (V _REF ) becomes smaller in the next cycle. By repeating this operation, the intensity of the pulse laser (Lp) can be stabilized regardless of temperature fluctuations or gas deterioration.

<Second Embodiment>

Consider a case where the duty ratio DR of the timing signal S1 changes, that is, a situation where at least one of the pulse width (excitation time) and the repetition frequency of the timing signal S1 changes. As described above, the second detection signal Vs2 (DVs2) represents the effective intensity (I _eff ) of the pulse laser multiplied by the duty ratio (DR). Therefore, in a system where the duty ratio (DR) is variable, the second detection signal DVs2 or its target value (D _REF ) can be scaled according to the duty ratio (DR).

Fig. 9 is a block diagram of the laser control device 140B according to the second embodiment. _The correction unit 144B adjusts the correction amount (D CMP) so that the value DVs5 (=DVs2/DR) obtained by dividing the second detection signal DVs2 by the duty ratio (DR) is close to the target value (D _REF ). do.

The laser control device 140B includes a duty ratio detector 170 in addition to the laser control device 140A of FIG. 7. The duty ratio detector 170 detects the duty ratio (DR). For example, the duty ratio detector 170 may detect the duty ratio DR based on the first detection signal Vs1 indicating the intensity of the pulse laser Lp. The binarization circuit 172 is a comparator, and compares the first detection signal Vs1 with a predetermined threshold value and binarizes it into high and low (1/0). The smoothing circuit 174 is a low-pass filter with the same characteristics as the smoothing circuit 142, and smoothes the binarized third detection signal Vs3 to generate the fourth detection signal Vs4. The fourth detection signal Vs4 represents the duty ratio (DR) described above.

The correction unit 144B includes an A/D converter 162 and a divider 164 in addition to the correction unit 144A in FIG. 7. The A/D converter 162 converts the fourth detection signal Vs4 into a digital value DVs4. Divider 164 divides DVs2 by DVs4 to generate scaled DVs5. DVs5 represents the effective intensity (I _eff ) of the pulse laser (Lp).

According to the laser control device 140B of FIG. 9, the effective intensity (I _eff ) of the pulse laser can be stabilized in a system where the duty ratio (DR) changes.

However, the configuration of the duty ratio detector 170 is not particularly limited. If the duty ratio of the timing signal S1 can be approximated to the duty ratio of the light emission period, the timing signal S1 may be input to the smoothing circuit 174.

<Third Embodiment>

Fig. 10 is a block diagram of a laser control device 140C according to the third embodiment. The correction unit 144C adjusts the correction amount D _CMP so that the second detection signal DVs2 is close to the target value D _REF multiplied by the duty ratio DR D _REF '(=D _REF × DR). do. The correction unit 144C is provided with a multiplier 166 instead of the divider 164 of the correction unit 144B in Fig. 9.

<Example 4>

Fig. 11 is a block diagram of a laser control device 140D according to the fourth embodiment. The correction unit 144D may separately detect the emission time (Te) and repetition period (Tp). The repetition period Tp may use the pulse width of the timing signal S1.

The correction unit 144D may adjust the correction amount D _CMP so that the value E _FB obtained by multiplying DVs2 by Tp is close to the target value E _REF obtained by multiplying D _REF by Te. Multipliers 169a and 169b perform multiplication. E _{REF =} D _REF That is, the correction unit 144D adjusts the reference voltage V _REF so that the energy error ΔE(n) approaches zero, or in other words, the energy per pulse approaches the target value.

(Second Embodiment)

In the first embodiment, the effective intensity of the pulse laser Lp was stabilized at the target value, but application of the present invention is not limited to this. Depending on the purpose of the laser and the type of processing, the energy per pulse may affect processing precision. In this case, the energy per pulse may be stabilized at the target value.

In the second embodiment, the excitation time Ton' for supplying the excitation signal S4 to the laser control device 140 is adjusted. Fig. 12 is a block diagram of the laser control device 140E according to the second embodiment. The basic configuration of the correction unit 144E is the same as the correction unit 144D in FIG. 11, but the correction target is the aftershock time Ton'. The command value of the excitation time Ton' can be the value obtained by adding the correction amount D _CMP (n) to the pulse width Ton of the timing signal S1.

The excitation signal generator 146 supplies an excitation signal (S4) to the laser oscillator 110 during the excitation time Ton'.

According to the second embodiment, the energy per pulse can be stabilized.

As mentioned above, the present invention has been explained based on several embodiments. These embodiments are examples, and it is understood by those skilled in the art that various modifications are possible in the combination of each component or each processing process, and that such modifications are also within the scope of the present invention. Below, these modified examples will be described.

The first embodiment and the second embodiment may be combined. In other words, both the excitation time Ton and the direct current voltage (V _DC ) may be controlled.

In addition, the correction target by the laser control device 140 is not limited to the direct current voltage (V _DC ) and the excitation time Ton.

Fig. 13 is a block diagram of a laser device 100F according to a modified example. The laser device 100F further includes a chiller 102 and a blower 104 for cooling the laser oscillator 110 and stabilizing the temperature. The laser control device 140 may correct the flow rate of the chiller 102 or the set temperature of the coolant of the chiller 102. Alternatively, the laser control device 140 may correct the rotation speed of the blower. These corrections may be performed alone or in combination with corrections for direct current voltage (V _DC ) and excitation time Ton.

Although the present invention has been described using specific phrases based on the embodiments, the embodiments only show one aspect of the principle and application of the present invention, and the embodiments do not include the spirit of the present invention defined in the claims. Many modifications and changes in arrangement are permitted as long as they do not deviate from the above.

100 laser device
110 Laser oscillator
120 power supply
140 Laser control device
142 Smoothing circuit
144 Compensation Department
146 Aftershock signal generator
150 A/D converter
152 subtractor
154 Feedback Controller
156 adder
158 memory
160 D/A converter
162 A/D converter
164 Divider
166 multiplier
170 Duty ratio detector
172 Identification circuit
174 Smoothing circuit
180 Photodetector
200 DC power
202 bank capacitor
204 DC Link
210 charging circuit
230 charging controller
300 high frequency power
302 Boosting transformer
310 inverter
900 laser processing machine
910 optical system
920 Processing machine control device
930 stages
Lp pulse laser
S1 timing signal
S2 intensity command
S3 position control signal
S4 aftershock signal
S5 voltage command

Claims (8)

A processing machine control device that generates a pulse-shaped timing signal,
laser oscillator,
A power supply device that supplies burst-like high-frequency voltage to the laser oscillator;
A photodetector that detects the pulse laser output from the laser oscillator and generates a pulse-like first detection signal;
According to the timing signal, an excitation signal is applied to the power supply to generate the high-frequency voltage, and the first detection signal is smoothed to generate a second detection signal, and the power supply is based on the second detection signal. Equipped with a laser control device that controls the state of the device,
The duty ratio of the timing signal is variable,
The laser control device further includes a duty ratio detector that detects a duty ratio, which is the ratio of the emission time and repetition period of the pulse laser, and scales the second detection signal or its target value according to the duty ratio,
The duty ratio detector,
A laser processing machine characterized by generating a third detection signal by binarizing the first detection signal, and generating a fourth detection signal representing the duty ratio by smoothing the third detection signal. According to paragraph 1,
The laser processing device is characterized in that the laser control device adjusts the amplitude of the high frequency voltage. According to paragraph 1,
The laser processing device is characterized in that the laser control device controls the generation time of the high frequency voltage. A power supply device that drives a laser oscillator based on a pulse-phase timing signal,
A direct current power source that generates direct current voltage,
a high-frequency power supply that converts the direct current voltage into a high-frequency voltage and supplies the high-frequency voltage in bursts to the laser oscillator according to the timing signal;
A photodetector that detects the pulse laser output from the laser oscillator and generates a pulse-like first detection signal;
A laser control device is provided for smoothing the first detection signal to generate a second detection signal and adjusting at least one of the DC voltage of the DC power source and the operation time of the high frequency power source based on the second detection signal. do,
At least one of the pulse width and frequency of the timing signal is variable,
The laser control device further includes a duty ratio detector that detects a duty ratio, which is the ratio of the emission time and repetition period of the pulse laser, and scales the second detection signal or its target value according to the duty ratio,
The duty ratio detector binarizes the first detection signal to generate a third detection signal, and smoothes the third detection signal to generate a fourth detection signal indicating the duty ratio. A processing machine control device that generates a pulse-shaped timing signal,
laser oscillator,
A power supply device that supplies burst-like high-frequency voltage to the laser oscillator;
A photodetector that detects the pulse laser output from the laser oscillator and generates a pulse-like first detection signal;
According to the timing signal, an excitation signal is applied to the power supply to generate the high-frequency voltage, and the first detection signal is smoothed to generate a second detection signal, and the power supply is based on the second detection signal. Equipped with a laser control device that controls the state of the device,
The laser control device includes a smoothing circuit composed of an analog circuit that inputs the first detection signal and outputs the second detection signal, and the time constant of the smoothing circuit is 5 times the period of the first detection signal. A laser processing machine characterized in that it is 50 to 50 times faster. delete delete delete