JPS6022628Y2 - Laser power supply - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an improvement of a laser power supply device that controls the waveform of laser light.

[Technical background of the invention]

FIG. 1 is a block diagram showing a conventional laser power supply device, which has a structure in which the oscillation repetition rate of a gate pulse laser is particularly increased and the irradiation time can be varied over a wide range.

That is, this device includes a control rectifying element 4 that controls charging of a voltage output from a DC power supply 1 to a charging/discharging capacitor 3 via a waveform shaping coil 2, and a control rectifying element 4 that controls charging of a voltage output from a DC power supply 1 to a charging/discharging capacitor 3 via a waveform shaping coil 2; The control rectifier 7 supplied from the flash lamp 6 and the charging voltage of the charging/discharging capacitor 3 are applied to the control rectifier 7 and reverse biased to turn it into an off state, which is referred to as commutation and hereinafter referred to as such.

), and a control rectifier element 8 for stopping light emission of the flash lamp 6, and these control rectifier elements 4.7.
8 is controlled by a gate pulse control section:9.

This gate pulse control section 9 is connected to a clock pulse generator 10.
In response to the clock pulse from the clock pulse generator 10, a gate pulse is generated to cause the control rectifier elements 4, 7 .
8 gate pulse generators 11.12.
13, and a delay circuit 14.15 that sets the control timing of each control rectifying element 4, 7.8.

16 is a trigger electrode that activates the flash lamp 6 by a trigger signal from a trigger voltage generator (not shown); 17 is a laser material; 18 is a condenser mirror;
9 and 20 are a mirror surface body and a semi-mirror surface body, which together form a resonator; 21 is a condenser lens; and 22 is a workpiece.

To describe the operation of the above device in detail, first, the control rectifying element 4 is ignited to charge the charging/discharging capacitor 3 with the voltage of the DC power supply 1.

After that, the timing control rectifier 7 shown in FIG.
is ignited to apply the voltage of the DC power source 1 to the flash lamp 6.

Therefore, this flash lamp 6 starts emitting light, and this light is collected by the condensing mirror 18 into the laser material 17,
The laser material 17 emits laser light excited by a resonator consisting of a mirror body 19 and a semi-transparent mirror body 20.

This laser light passes through the semi-transparent mirror body 20 and the condensing lens 2
1 and irradiates the workpiece 22.

Here, the workpiece 22 is processed.

Thereafter, the control rectifier 8 is ignited by a processing end timing signal outputted from the delay circuit 15 via the gate pulse generator 13, and the control rectifier 7 is set to reverse bias and turned off. The lamp 6 stops emitting light.

By the way, the irradiation characteristics of this laser beam are determined by the light emission characteristics of the flash lamp 6, which are shown in FIG.

Note that the vertical axis is the light emission output p, and the horizontal axis is the time t.

That is, from time t2 to time t2, it rises slowly depending on the conduction time of the control rectifier 7, and after t2, it falls with a peak waveform A as shown in the figure at time t3.

The degree of protrusion of this peak waveform A is determined by the capacitance value of the charging/discharging capacitor 3.

[Problems with background technology]

By the way, two metal plates 22 are
When welding the butt portions a and 22b, it is necessary to select an appropriate capacitance value for the charge/discharge capacitor 3.

That is, when the capacitance value of this charging/discharging capacitor 3 is set to a value greater than the commutation value, as shown in the welded cross-sectional view of FIG.
Voids 24 are generated inside the welded solidified portion 23 shown by diagonal lines,
Splash particles B (splash) are likely to occur in the surrounding area.

Furthermore, although the laser beam having the waveform shown in FIG. 2 is suitable for cutting and drilling, it is not optimal for welding that requires deeper penetration such as spot welding.

As described above, the conventional device has the disadvantage that once the capacitance value of the charge/discharge capacitor 3 is set, the subsequent use is limited to a very narrow range.

[Purpose of invention]

The purpose of this invention is to provide a laser power supply device that can variably set the pulse width of pulsed light for laser excitation and control the falling part of the pulsed light to perform optimal processing depending on the processing application. shall be.

[Summary of the idea]

In order to achieve the above object, the present invention includes a power supply section,
first to third control rectifiers that are turned on at predetermined respective timings; a discharge light emitting body to which a voltage is applied from the power supply section when the first control rectifiers are turned on; and the second and third control rectifiers. The first and second charging/discharging capacitor sections having different time constants perform charging and discharging operations depending on the on state of the controlled rectifying element No. 3. In this laser power supply device, the discharge voltage of the second charging/discharging capacitor section is applied to the discharge luminous body when the control rectifying element is turned off.

[Example of idea]

An embodiment of the present invention will be explained using the constituent countries shown in FIG. 4 and the characteristic diagram shown in FIG. 5.

In FIG. 4, 1 is a DC power supply, and two control rectifiers 30 and 31 are branch-connected to the output side of the DC power supply, and a resonant charging coil 32 is connected to the output side of the control rectifier 30. .

Furthermore, a series circuit 36 consisting of a waveform shaping coil 33 (air-core coil or iron-core coil), a charging/discharging capacitor 34, and a switch 35 is connected between the other end of the resonant charging coil 32 and the ground.

The interconnection point between the series circuit 36 and the waveform shaping coil 32 is grounded via a charging/discharging capacitor 37, and is further connected to the flash lamp 6 via a control rectifying element 38 and a waveform shaping coil 39 to apply voltage to the flash lamp 6. I am trying to supply voltage.

Further, the control rectifier element 31 is arranged in parallel to these control rectifier elements 30, 32, 38.

Further, a trigger electrode 16 is wrapped around the flash lamp 6, and a laser material 17 and a resonator (separated from a mirror surface 19 and a semi-transparent mirror surface 20) equipped with a focusing mirror 18 are located near the flash lamp 6. A light lens 21 is arranged to irradiate the workpiece 22 with laser light generated by the flash lamp 6 emitting light.

The three controlled rectifying elements 30, 31, and 38 are controlled to fire at predetermined timings by a gate pulse control section 9 having a configuration similar to that shown in FIG.

Next, the operation of the laser power supply device configured as above will be explained.

First, after closing the switch 35, the gate pulse controller 9 outputs a gate pulse to ignite the control rectifying element 30.

As a result, the voltage output from the DC power supply 1 is resonantly shaped into a waveform by the resonant charging coil 32, and then charged into the two charging/discharging capacitors 34 and 37.

Therefore, in this case, the two charging/discharging capacitors 34, 37
The total charging voltage is approximately twice the voltage of the DC power supply 1.

Also, at this time, the charged voltage is
, resonant charging/waveform shaping coil 33 and charging/discharging capacitor 3
The resonant charging voltage is determined by 4.37.

Next, at time F1, a gate pulse is output from the gate pulse control section 9 to ignite the control rectifying element 31.

At the same time, from the trigger voltage generator (not shown)) IJ
A Gar pulse is applied to the trigger electrode 16.

Therefore, an applied voltage is supplied from the DC power source 1 to the flash lamp 6 via the control rectifying element 31 and the waveform shaping coil 39, and the flash lamp 6
emits excitation light.

The workpiece 22 is irradiated with laser light in accordance with this light.

Furthermore, at time F2, a gate pulse is output from the gate pulse controller 9 to ignite the control rectifier 38.

As a result, the voltage charged in the charge/discharge capacitor 37 is first applied as a reverse voltage to the output side of the control rectifier 31 via the control rectifier 38.

As a result, the controlled rectifying element 31 has a characteristic turn-off time (
The current is commutated within a few tens of microseconds (usually several tens of microseconds).

Next, the control rectifying element 31 is commutated, and the voltage applied from the DC power source 1 to the flash lamp 6 is stopped. as control rectifier element 38
is applied to the flash lamp 6 via.

Since the discharge at this time is performed via the waveform shaping coil 33, the peak discharge current is sufficiently suppressed, and the discharge time constant can also be set long depending on the value of the waveform shaping coil 33, resulting in a flash lamp. In the light emission of No. 6, the peak waveform C immediately after the commutation is suppressed, and the pulsed light has a gradual falling waveform.

This light emission waveform is shown in FIG. 5a.

The gate pulse control unit 9 changes the control rectifier 31 from the on state at time T□ to the off state at time T2 (commuting effect due to the on state of the control rectifier 38) by adjusting the delay circuit 15. The time can be increased.

That is, time T2 can be set to time T'2 (T2<T'2), and pulsed light with a longer light emission time of the flash lamp 6 can also be obtained as shown in FIG.

In addition, in both FIGS. 5a and 5b, the vertical axis shows the light emission output P, the horizontal axis shows the light emission time T, and T3. T'3 indicates the light emission end time, and C indicates the peak waveform immediately after commutation.

A flash lamp with a gradual fall like this 6
If the abutting portion of the two metal sheets 22a and 22b is welded using the laser beam obtained by the emission of the The number of air bubbles generated can be minimized.

In addition, the welded surface can be finished flat and have sufficient strength.

In order to further suppress the peak waveform C immediately after the commutation shown in FIG. 5 a or b, the diode 4 shown by the dotted line in FIG.
This is made possible by connecting 0 to the control rectifying element 31 in parallel with reversed polarity, and it is possible to obtain pulsed light as shown in FIG. 7a or b.

Therefore, it is possible to deal with machining problems caused by peak waveforms.

Note that the vertical and horizontal axes in FIGS. 7a and 7b indicate the light emission output P and time T, as in FIG. 5, and C' indicates the peak waveform.

As described above, a first charging/discharging capacitor section consisting of the charging/discharging capacitor 37 and a second charging/discharging capacitor section consisting of the waveform shaping coil 33 and the charging/discharging capacitor 34 are provided, and the difference in discharge time constant between the two allows the Charge amount: 1
One is used to stop the main discharge light emission of the flash lamp 6, and the other is used for the fall of the light emission of the same lamp, thereby making it possible to form various light emission waveforms with a gradual fall or a wide light emission waveform. By turning off the switch 35, a steep falling waveform after commutation can be obtained, and the variety of light emission waveforms is further increased.

Further, the present invention is not limited to the above-mentioned embodiments, and for example, series circuits of the waveform shaping coil 33 and the charging/discharging capacitor 34 can be provided in multiple stages to increase the types of falling waveforms.

With this, by selecting the required number of stages, it is possible to obtain a falling waveform according to each processing purpose, and the range of processing applications is further expanded.

[Effect of idea]

As described above, according to the present invention, the falling waveform of the flash lamp's pulsed light emission can be changed into various types with a simple configuration of a coil, a capacitor, and a switch, and even when processing using laser light, the processing purpose A laser power supply that can improve the processing performance of laser processing by creating various waveforms with a steep falling edge, a gentle falling edge, or any waveform with an arbitrarily set pulse width. equipment can be provided.

[Brief explanation of the drawings] Figure 1 shows the configuration of a conventional laser power supply device, Figure 2 shows the light emission characteristics of the device with the configuration shown in Figure 1, and Figure 3 shows welding performed using the equipment shown in Figure 1. 4th cross-sectional view of the welded part when
The figure shows the constituent countries showing one embodiment of the laser power supply device according to the present invention, Fig. 5 shows the light emission characteristics of the device with the configuration shown in Fig. 4, and Fig. 6 shows the state when welding is performed using the device shown in Fig. 4. FIG. 7 is a sectional view of the welded portion of FIG. 7, and a light emission characteristic diagram obtained when a diode is newly added to the device shown in FIG. 4. 9... Gate pulse control section, 30...
First controlled rectifying element, 31... Second controlled rectifying element, 36... Second charging/discharging capacitor section, 3
7...First charging/discharging capacitor section, 38...
...Third controlled rectifier element, 40...Diode.

Claims (1)

[Scope of utility model registration request] a power supply section that supplies power; a date pulse control section that outputs first, second, and third gate pulse signals at predetermined timing; and a date pulse control section that outputs first, second, and third gate pulse signals at predetermined timing; first and second controlled rectifiers that are turned on by a gate pulse signal; first and second control rectifiers that have different time constants that charge the voltage of the power supply section when the first controlled rectifier is turned on; a part of the charging/discharging capacitor, a discharge light emitter that discharges and emits light in response to a voltage from the power supply section when the second control rectifying element is turned on, and a third charge/discharge capacitor that is output from the gate pulse control section.
The first and second charge/discharge capacitors are turned on in response to a gate pulse signal, and the charging voltage of the first and second charge/discharge capacitors is applied to the second control rectifier to turn them off, and the discharge light is emitted with a slow falling characteristic. a third controlled rectifying element that applies the charging voltage to the body.