JPH04258389A - Laser beam machine - Google Patents

Abstract

PURPOSE:To alway execute the optimum working even if the output loss value of the laser beam is changed on the optical system on the laser beam machine. CONSTITUTION:The laser beam B from the laser oscillator 29 is introduced with the optical system 31 having the bender mirror 30, irradiates the material 27 to be machined on the moving table. It is controlled with the numerical controller 34 based on the machining condition set preliminarily. Before the beginning of the machining, the light in the visible region of laser beam is outputted from the visible light of laser oscillator 35 to the optical route of the laser beam B, and its intensity of illumination is detected with the 1st and the 2nd illumination detecting sensors 36 and 37. Based on this detection, the value of output loss of the laser beam B on the optical system can be estimated and detected, the above machining condition is corrected corresponding to them.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus for processing workpieces such as metal plates by welding, cutting, drilling, etc.

0002

2. Description of the Related Art FIG. 2 shows an example of a laser processing apparatus used for processing, for example, metal plate materials. This thing is
A laser beam B output from a laser oscillator 1 is guided to a processing head 4 by an optical system 3 including a plurality of bender mirrors 2, is focused by a lens 5 provided in the processing head 4, and is directed from a nozzle 4a to a workpiece. It is designed to irradiate the processing point of the object 6. In addition, the processing head 4 has
A processing gas is supplied from a processing gas supply device 7, and is blown out from a nozzle 4a at the same time as the laser beam B. On the other hand, a moving table 8 on which the workpiece 6 is set
can be freely moved in the horizontal direction by an X-axis moving motor 9 and a Y-axis moving motor 10.

[0003] Such a laser processing apparatus includes a numerical control device 11 composed of a microcomputer or the like.
is provided. This numerical control device 11 controls the processing speed (the speed of movement of the moving table 8 in each axis direction), the output value and frequency of the laser beam B, which are set in advance by the operator.
Based on processing conditions such as pulse width, processing gas pressure and flow rate, the laser oscillator 1, processing gas supply device 7,
The motor 9 for moving the axis and the motor 10 for moving the Y-axis are controlled, so that the machining work is automatically executed.

0004

By the way, in the laser processing apparatus as described above, the bender mirror 2 constituting the optical system 3 has an extremely excellent reflectance at the beginning of use. With long-term use, physical and chemical deterioration and surface stains occur, resulting in a decrease in reflectance. If the reflectance of the bender mirror 2 decreases in this way, even if the laser beam B is output from the laser oscillator 1 at an output value suitable for processing, the output loss of the laser beam B will be relatively large while passing through the optical system 3. This causes a problem in which optimal machining cannot be performed. Such defects become a big problem especially in special processing such as thick plate cutting, fine cutting, and special welding.

One way to deal with such problems is to clean the bender mirror 2, but
Although it is possible to recover the reflectance to some extent, it is difficult to recover the reflectance by the time the product is first used, depending on cleaning. Of course, it would be possible to replace it with a new vendor mirror 2, but this would be economically disadvantageous. Therefore, when the reflectance of the bender mirror 2 decreases, processing conditions such as the output value of the laser beam B of the laser oscillator 1 are newly set in the numerical control device 11, even though the type of processing does not change. This would have to be redone, placing a heavy burden on the workers.

The present invention has been made in view of the above circumstances, and its purpose is to always perform laser processing at the optimum output value even if the degree of output loss of the laser beam in the optical system changes. Our goal is to provide a laser processing device that can. [Structure of the invention]

[0007]

[Means for Solving the Problems] A laser processing apparatus of the present invention includes a laser oscillator and an optical system for guiding a laser beam outputted from the laser oscillator to a processing point, and is configured to meet processing conditions set in advance. Based on this, the workpiece is processed by irradiating the workpiece with a laser beam,
The present invention is characterized in that it is provided with a means for detecting the output loss of the laser beam in the optical system, and a control means for correcting the processing conditions based on the detection by the detecting means.

[0008]

According to the above means, the laser beam output from the laser oscillator is guided to the processing point by the optical system, and the workpiece is processed. At this time, if there is deterioration such as a decrease in reflectance in the optical system, the output of the laser beam will be lost when passing through the optical system, but this output loss will be detected by the detection means. Then, based on the detection, the preset machining conditions are corrected by the correcting means, and the workpiece is machined using the corrected machining conditions. Therefore, even if the degree of laser beam output loss in the optical system changes, processing can be performed with the optimum laser beam output.

[0009]

[Embodiment] An embodiment of the present invention will be described below with reference to FIG. FIG. 1 schematically shows the overall configuration of a laser processing apparatus 21 according to this embodiment, and here, 22
is a moving table, which includes a Y-axis moving table 24 provided on a base (not shown) and moved in the Y-axis direction by a Y-axis moving motor 23, and an X-axis moving table 24 provided on this Y-axis moving table 24. It is composed of an X-axis moving table 26 that is moved in the X-axis direction by a moving motor 25. A workpiece 27 such as a metal plate is set on the moving table 22 (X-axis moving table 26), and the workpiece 27 is
3 and 25, it can be freely moved in the horizontal direction.

On the other hand, above the moving table 22,
A processing head 28 is fixedly provided. A laser beam B output from a laser oscillator 29 is guided to the processing head 28 while being reflected by an optical system 31 comprising three bender mirrors 30, and a processing gas Processing gas (shielding gas) is supplied from a supply device 32. The processing head 28 focuses the laser beam B introduced through the optical system 31 using a built-in lens 33, and irradiates the processing point A of the workpiece 27 from the nozzle 28a at the tip. and the nozzle 28a
Processing gas is sprayed from there toward the processing point A.

[0011]The laser processing device 21 includes:
A numerical control device 34 composed of a microcomputer or the like is provided. This numerical control device 34 controls the machining speed (piercing time and moving speed of the moving table 22 in each axis direction), the output value, frequency, pulse width, and machining gas pressure set by the operator in advance. Based on processing conditions such as flow rate, the laser oscillator 29
, processing gas supply device 32, X-axis movement motor 25 and Y
The shaft moving motor 23 is controlled so that machining operations are automatically executed. In this case, these processing conditions are optimal for performing the desired processing on the workpiece 27, with reference to the beginning of use of the laser processing device 21, that is, when the reflectance of each bender mirror 30 is approximately 100%. set to become something.

Now, in the laser processing apparatus 21 configured as described above, the laser beam B in the optical system 31 is
Means are provided for detecting a power loss of. In this embodiment, as this detection means, the reflectance of the bender mirror 30 is detected by measuring the illuminance using a visible light laser, and based on this, the laser beam B is indirectly detected.
A mechanism is provided to detect the degree of output loss.

That is, a visible light laser (He-Ne laser) oscillator 35 is incorporated in the laser oscillator 29, and is configured to output a visible light laser beam along an optical path that coincides with the optical path of the laser beam B. It has become. In the optical path of this visible laser beam (the optical path of laser beam B), a first illuminance detection sensor 36 is provided at a position immediately after the laser oscillator 29, and a first illuminance detection sensor 36 is provided in the optical path of the visible laser beam (the optical path of the laser beam B). A second illuminance detection sensor 37 is provided at the rear portion. These first and second
The illuminance detection sensors 36 and 37 are each provided in such a manner that its detection portion can be moved into the optical path (indicated by a two-dot chain line),
The illuminance of the visible laser beam at that position can be detected.

The detection data from the first and second illuminance detection sensors 36 and 37 are input to a processing condition calculation and correction device 38. This processing condition calculation correction device 38 calculates the degree of decrease in illuminance in the optical system 31 (reflectance of the bender mirror 30) from the difference in illuminance detected by the two illuminance detection sensors 36 and 37, The degree of output loss of the beam B in the optical system 31 is estimated. The output loss data calculated by the processing condition calculation correction device 38 is input to the numerical control device 34, and the numerical control device 34 corrects the processing conditions based on this output loss,
Each mechanism is controlled based on the corrected machining conditions. In this way, the numerical control device 34 functions as a control means according to the present invention.

Furthermore, when the output loss exceeds a preset threshold, the numerical control device 34 displays a message on the display device 39 to the effect that the bender mirror 30 should be cleaned or replaced. It looks like this.

Next, the operation of the above configuration will be described. In starting a predetermined processing operation on the workpiece 27, first, the visible light laser oscillator 35 is driven to output a visible light laser beam to the optical path of the laser beam B. First, the illuminance of this visible laser beam is
The illuminance is measured by the first illuminance detection sensor 35 at the position immediately after the visible light laser beam is output from the optical system 31. It is measured by the second illuminance detection sensor 36.

These first and second illuminance detection sensors 36
The detection data of
From the difference in illuminance, the degree of decrease in illuminance in the optical system 31 (reflectance of the bender mirror 30) is calculated, and the degree of output loss of the laser beam B in the optical system 31 is estimated. As a result, when the reflectance of the bender mirror 30 input in advance to the numerical control device 34 is approximately 100%, the processing speed (piercing time and moving speed of the moving table 22 in each axis direction), the laser beam B Processing conditions such as output value, frequency, pulse width, and processing gas pressure and flow rate are corrected.

After that, based on the corrected processing conditions,
The laser oscillator 29, the processing gas supply device 32, the X-axis movement motor 25, and the Y-axis movement motor 23 are controlled by the numerical control device 34, and a predetermined process is performed on the workpiece 27. At this time, even if the reflectance of the bender mirror 30 that constitutes the optical system 31 has decreased compared to when it was first used due to physical or chemical deterioration or surface dirt, the current optical The machining work is performed under optimal machining conditions commensurate with the output loss in the system 31.

Furthermore, if the reflectance of the bender mirror 30 exceeds the threshold value at this time, a message to that effect is displayed on the display device 39, and the operator is instructed to replace or clean the bender mirror 30 based on the display. This allows you to know when the right time is.

As described above, according to this embodiment, even if there is an output loss of the laser beam B in the optical system 31 due to a decrease in the reflectance of the bender mirror 30, the processing conditions can be adjusted according to the magnitude of the output loss. will be corrected. Therefore, unlike the conventional method, in which the processing conditions had to be newly set in the numerical control device 11 when the reflectance of the bender mirror 2 decreased, the processing conditions can be constantly set without imposing a burden on the operator. Laser processing can be performed under optimal processing conditions.

Furthermore, in this embodiment in particular, a message indicating that the bender mirror 30 should be replaced or cleaned is displayed on the display device 39 in accordance with the detected output loss, so that the operator can easily know when it is time to clean the bender mirror 30 or to clean it. It also has the advantage of knowing when to replace it.

In the above embodiment, the illuminance of the visible laser beam is detected by the two illuminance detection sensors 36 and 37, and the output loss is indirectly detected from the reflectance in the optical system 31. As the detection means, for example, an output detection sensor that can directly detect the output of the visible laser beam may be provided in place of the illuminance detection sensors 36 and 37, or a sensor that directly detects the output of the laser beam B for processing. may be provided. In addition, the present invention is not limited to the above embodiments, and various changes can be made without departing from the scope of the invention.

[0023]

Effects of the Invention As is clear from the above description, the laser processing apparatus of the present invention includes a means for detecting the output loss of a laser beam in an optical system, and a processing condition that can be adjusted based on the detection by the detection means. Since a control means for correction is provided,
Even if the degree of output loss of the laser beam in the optical system changes, the excellent effect is that laser processing can always be performed at the optimum output value.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing the overall configuration of a laser processing device showing an embodiment of the present invention.

[Figure 2] A diagram equivalent to Figure 1 showing a conventional example

[Explanation of symbols]

21 is a laser processing device, 22 is a moving table, 27 is a workpiece, 28 is a processing head, 29 is a laser oscillator, 30
is a bender mirror, 31 is an optical system, 34 is a numerical control device, 35 is a visible light laser oscillator, 36 is a first illuminance detection sensor, 37 is a second illuminance detection sensor, 38 is a processing condition calculation correction device, and 39 is a display. Show the device.

Claims (1)

[Claims] Claim 1: A laser oscillator and an optical system for guiding a laser beam outputted from the laser oscillator to a processing point, and irradiating the workpiece with the laser beam based on preset processing conditions. The processing is characterized in that it is provided with means for detecting an output loss of the laser beam in the optical system, and a control means for correcting the processing conditions based on the detection by the detection means. Laser processing equipment.