JPH0714097B2 - Laser output controller - Google Patents

Description

Description: INDUSTRIAL APPLICABILITY The present invention relates to a laser output command sequentially issued from an output setting device via an NC tape or the like during laser processing so that the command value and the actual laser output value match. The present invention relates to a laser output control device improved.

2. Description of the Related Art In cutting processing using laser light, it is necessary to set a laser output suitable for the material of the workpiece and the processing speed. That is, the processing speed is variously changed depending on the thickness of one type of work or the required processing accuracy. When the processing speed changes during processing in this way, it is necessary to prevent the deterioration of cutting quality by changing the laser output according to the speed.

FIG. 6 is a block diagram of a conventional laser output control device that has been used for such a purpose. Half mirror A,
B is arranged so as to face each other through the anode C and the cathode D, and forms a laser resonator. A part of the laser light is guided to the detector E by the half mirror A and is guided to the converter F for correcting the non-linearity of the detector E, and the laser output is displayed on the display G. On the other hand, from the half mirror B,
A laser beam for processing is taken out and a laser beam is guided to a work W or a damper I by a mirror H, and the damper I absorbs laser energy during non-processing. The current control circuit J controls the power supply K so that a discharge current proportional to the voltage applied to its input is given to the laser resonator, and the laser power is controlled by the magnitude of this discharge current.

On the other hand, although the output characteristics of the laser oscillator output are not constant due to the season, installation environment, secular change, etc., the discharge current and the laser output have characteristics as shown in FIG. 7 (a). The characteristics of the voltage applied to the input terminal of the current control circuit J and the laser output are also as shown in FIG. 7 (b). Therefore, when the command output of the laser oscillator is changed to a desired value during laser processing, the current control circuit J is provided with a plurality of laser output setting volumes L, and each volume L is preset.
Are set so that the actual laser output becomes a desired laser output, and during processing, the volume L is switched according to each command laser output programmed by the NC unit M to perform processing.

However, this method requires a large number of setting volumes L when there are many types of command laser output used during processing, and it is necessary to adjust each of these volumes L to a desired output before processing. However, the adjustment required a lot of labor and time. Further, even if it is set once, the characteristics of the discharge current and the laser output change due to the above reason and the gas temperature change in the laser oscillator, so that there is a drawback that it is necessary to adjust all the volumes L each time. It was

SUMMARY OF THE INVENTION The present invention has been made in order to eliminate such drawbacks, and an actual laser output value with respect to various preset command voltage values is automatically sampled, and this sampling is performed. Since the required command voltage for each command output is automatically determined based on this, the time and effort for setting the laser output is not required and the burden on the operator is greatly reduced.
Operation can be started quickly, the actual power as commanded by the output setting means can be obtained, and moreover, unlimited types of laser output can be commanded according to changes in laser processing speed, etc. An object of the present invention is to provide a laser output control device capable of improving reproducibility.

Therefore, the present invention provides a plurality of types of command voltages measured in advance to the current control means for controlling the current to the laser oscillator, and stores and samples the actual laser output value for each of the command voltage values. Determine the required command voltage value based on the sampled memory value for the command output value specified by the output setting means based on the instruction from the NC device etc., and give this command voltage to the current control means. Is used to control the current to the laser oscillator.

Configuration of the Invention Hereinafter, the configuration of the present invention will be specifically described with reference to FIGS. 1 to 5.

In FIG. 1, 1 is a discharge part 4 between an anode 2 and a cathode 3.
And a laser oscillator that outputs a laser from the discharge unit 4. The laser oscillator 1 has a pair of half mirrors 5 and 6 arranged to face each other via the discharge unit 4. Reference numeral 7 is a detector that detects a laser output by the laser beam that has passed through the one half mirror 5, and 8 is a converter that outputs a value proportional to the signal extracted from the detector 7. The output detection means 9 is constituted by the converter 8. Reference numeral 10 is an A / D converter for converting the output of the converter 8 into a digital signal. Reference numeral 11 is a power supply for supplying a voltage between the anode 2 and the cathode 3 of the laser oscillator 1, and 12 is a current control circuit for controlling the current to the laser oscillator 1, which is composed of the current control circuit 12 and the power supply 11. The current control means 13 is configured. 14 is the current control circuit 12
It is a D / A converter that gives a current value to. Reference numeral 15 is an output setting means for designating a command output value to the laser oscillator 1 based on an instruction from an NC device or the like, and 16 is a switcher for switching between a sampling mode and an operation mode. Also, 17
Is a CPU having the A / D converter 10, the setting means 15, each input circuit of the switching device 16 and the output circuit to the D / A converter 14, and the CPU 17 is the sampling means 18 for performing the sampling mode and the operation It has both functions of the output control means 19 for performing the mode. Reference numeral 20 denotes a mirror that guides the processing laser beam extracted from the other half mirror 6 onto the work W during processing and to the damper 21 during non-processing.

A part of the laser light extracted from the laser oscillator 1 is guided to the detector 7 from the half mirror 5 and is converted into an output proportional to the laser output via the converter 8 and the A / D converter. It is taken in by the CPU 17 as a digital signal by 10. Also, this CPU17 is
A signal for controlling the laser output is output to the current control circuit 12 via the D / A converter 14, and the sampling mode from the switch 16 and the input for accepting the operation mode and the laser output from the setting means 15 It has an input that accepts a command value.

Operation of the Invention Next, the operation of the present invention will be described with reference to the flow charts of FIGS. 4 and 5.

First, the selector of the switch 16 is set to the sampling mode. As a result, the sampling means 18 works and the CPU 17
The preset stepwise command voltage V _j as shown in FIG. 2 is output to the current control circuit 12 via the converter 14. The number N of steps of this staircase is determined by the required resolution of the command output value, and the time Δt from step to step is determined by the response time of the detector 7 required for sampling, for example.
Further, the maximum voltage V _max (= V _N ) of this staircase wave is determined by the maximum value of the allowable current of the laser oscillation tube.

As shown in the flow of FIG. 4, the CPU 17 first outputs the first voltage V ₁ of the staircase wave, then reads the laser output value P ₁ from the detector 7 at that time, and stores it in the memory. Then, after Δt, the next command voltage V ₂ is output and the laser output value P ₂ from the detector 7 is read and stored in the memory. By repeating the same processing N times, the third time is stored in the memory of the CPU17.
As shown in the figure, a sampled data table 22 of the laser outputs P _{1 to} P _N for each preset voltage V _{1 to} V _N is created.

Next, when performing laser processing, the selector of the switch 16 is switched to the operation mode. As a result, the output control means 19
5, the CPU 17 reads the laser output value Pcom commanded by the output setting means 15 via NC tape or the like as shown in the flow of FIG. 5, and based on the stored value on the data table 22 created in the sampling mode. Required command voltage Vcom
Is determined. That is, if the value equal to the output value P _j which command output value Pcom is stored, the command voltage V _j for the output value P _j is directly outputted to the D / A converter 14.
However, if the command output value Pcom is not in the stored value, select the range between the two points (P _j and P _j-1 ) where the command output value Pcom exists,
Proportional distribution is made within the range from the data of these two points (P _j and P _j-1 ) and the required command voltage value Vcom for the command output value Pcom is calculated. That is, it is obtained by the following formula.

Then, the calculated data Vcom is used for the D / A converter 14
Is output to.

In this way, it is possible to set the command output value Pcom innumerably according to the change of the material of the work piece and the processing speed even during the processing, and the CPU 17 repeats the above operation mode for each command and commands it. By calculating the voltage Vcom and controlling the current applied to the laser oscillator 1, it is possible to obtain the actual power that matches the commanded output value Pcom.

EFFECTS OF THE INVENTION According to the present invention, a plurality of kinds of command voltages preset in the current control means are applied stepwise by the sampling means, and actual laser output values corresponding to the respective command voltage values are read to read the command voltage values. Since a data table of laser output values is automatically created, sampling is very easy, and a large amount of data can be automatically sampled at any time in a short time regardless of the installation environment.

At the time of laser processing, the output control means automatically outputs an appropriate command voltage value based on the data table, regardless of the presence or absence of the same data, on the data table sampled for the command output value arbitrarily commanded. Therefore, good processing can always be performed.

That is, regardless of the place to be processed or the date and time, the actual power as commanded by the output setting means can be obtained, and after sampling, there is no limitation on the type of output value that can be commanded.
An unlimited number of laser outputs can be commanded according to changes in the material of the work piece, the laser processing speed, etc. Therefore, the processing efficiency and the reproducibility of the processing can be improved.

[Brief description of drawings]

1 is a block diagram showing the device of the present invention, FIG. 2 is a diagram showing command voltage waveforms, FIG. 3 is a diagram showing a data table,
FIG. 4 is a flow chart of the sampling mode, FIG. 5 is a flow chart of the operation mode, FIG. 6 is a block diagram showing a conventional device, and FIGS. 7 (a) and 7 (b) are diagrams showing laser output characteristics. . DESCRIPTION OF SYMBOLS 1 ... Laser oscillator, 9 ... Output detection means, 13 ... Current control means, 15 ... Output setting means, 17 ... CPU, 18 ... Sampling means, 19 ... Output control means, 22 ... Data table

Claims (1)

[Claims] 1. A laser oscillator, an output detection means for detecting a laser output of the laser oscillator, a current control means for controlling a current to the laser oscillator, and a plurality of types of commands preset in the current control means. Sampling means for creating a data table of the command voltage value and the laser output value by applying the voltage stepwise and reading and storing the laser output value for each command voltage value from the output detection means, and the command to the laser oscillator. If the output setting means for instructing the output value and the command output value instructed by the output setting means are equal to the laser output value on the data table, the command voltage value for this laser output value is directly used as the command output value. Determine the required command voltage value for
If the command output value is not the laser output value on the data table, the range between the two laser output values on the data table in which this command output value exists is selected and the two laser output values corresponding to the two laser output values are selected. A command voltage value necessary for the command output value is determined by proportional distribution within the range between the command voltages, and an output control means for applying the determined command voltage to the current control means is provided. Laser output control device.