JPH0985472A - Method for detecting laser output and laser machining head using the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for accurately detecting a laser output at or near the laser machining position and to obtain a laser machining head using the detecting method. SOLUTION: In the method for detecting a laser output emitted to a work W from the machining head of a laser beam machine, a device 77 for measuring the output is provided in the machining head, detecting the output incident on the condensing lens 57 of the machining head. In the laser machining head provided with an optical system consisting of two reflection mirrors that make a laser beam from the light source incident on the condensing lens 57, the reflection mirror on the optical axis of the condensing lens 57 is constituted of a translucent mirror 55 capable of transmitting a part of the laser beam, and then a device for measuring the output so transmitted is provided in the laser beam machining head.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser output detection method and a laser processing head using the detection method.

[0002]

2. Description of the Related Art Carbon dioxide laser processing equipment or YAG
The output of the laser processing device or the like is detected in the laser oscillator. More specifically, a minute laser beam is taken out from a rear mirror that constitutes a laser oscillator, the laser beam is received by a calorimeter, and converted into an actual output of the laser oscillator.

[0003]

The detection of the laser output of the above-mentioned conventional laser processing apparatus detects the output of the laser oscillator, and the laser output at the position where the laser processing is actually performed is detected. It is not detected. In a general laser processing device, laser light from a laser oscillator is guided to a laser processing head provided in a positioning device of the laser processing device through an optical path of several meters.

An optical system such as a collimator and a plurality of bending mirrors is usually provided in the optical path of several meters. In the case of a YAG laser, an optical system such as an optical fiber and a collimator at the laser light emitting end of the optical fiber is provided. Then, the laser light that has passed through these optical systems is finally incident on the condenser lens of the laser processing head and is condensed and irradiated onto the surface of the workpiece.

Therefore, the detected output of the laser oscillator is different from the output on the surface of the workpiece. That is, due to energy loss due to the optical system from the laser oscillator to the surface of the workpiece, the laser output at the processing position is reduced as compared with the laser output of the oscillator. The energy loss is not constant and changes with time due to deterioration of the laser oscillator and the optical system.

[0006] The change in output during laser processing has a great influence on the processing quality, and in the case of welding processing in particular, it may result in defective welding in which the penetration is insufficient even though there is no apparent problem. Therefore, it is important to manage the laser output at the processing position, but there is a problem that the change in output due to the deterioration of the optical system cannot be detected by the conventional output detection method.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method of accurately detecting a laser output at or near a laser processing position and a laser processing head using the detection method. Is to provide.

[0008]

According to a first aspect of the present invention, there is provided a laser output detecting method, wherein the laser output measuring device is a laser output measuring device for irradiating a workpiece with a laser processing head of the laser processing device. It is characterized in that it is provided at a fixed position in the vicinity of the processing table of the processing apparatus, and the laser output is detected by moving the laser processing head to the installation position of the laser output measuring apparatus at regular time intervals.

Therefore, it is possible to detect the laser output at the processing position, which changes with time due to deterioration of the laser oscillator and the optical system, every time a fixed time elapses.

According to a second aspect of the present invention, there is provided a laser output detecting method, wherein a laser output measuring device is provided inside the laser processing head in a method for detecting a laser output applied to a workpiece from a laser processing head of the laser processing device. It is characterized in that the laser output incident on the condenser lens of the laser processing head is detected.

Therefore, it is possible to detect the laser output in the vicinity of the processing position, which changes with time due to deterioration of the laser oscillator and the optical system, every time a fixed time elapses.

A laser processing head according to a third aspect is
In a laser processing head provided with an optical system composed of two reflecting mirrors for making laser light from a laser light source incident on a condenser lens, a reflecting mirror on the optical axis of the condenser lens is part of the laser light. Is formed of a semi-transparent mirror capable of transmitting the laser beam, and an output measuring device for measuring the output of the part of the laser beam transmitted through the semi-transparent mirror is provided inside the laser processing head.

Therefore, it is possible to detect the laser output in the vicinity of the processing position, which changes with time due to deterioration of the laser oscillator and the optical system, inside the laser processing head. Therefore, there is an advantage that the laser output can be detected without moving the laser processing head to the measuring device.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a laser output detecting method of the present invention and a laser processing apparatus using the detecting method will be described below with reference to the drawings.

Referring to FIG. 1, FIG. 1 shows an example of a laser processing apparatus using the laser output detecting method of the present invention. The laser processing apparatus 1 shown in FIG. 1 is a laser processing apparatus using a known playback type articulated robot 3, and the articulated robot 3 is installed near a YAG laser oscillator 5 and the articulated robot 3 is installed. The YAG laser oscillator 5 and the optical fiber 9 on the wrist portion 7 of the
The laser processing head 11 connected with is fixed. The laser processing head 11 is provided with a known CCD camera 13 for observing the surface of the material to be processed.

A table 15 is provided in front of the articulated robot 3 (on the right side in FIG. 1), and a workpiece W is placed on the table 15 for laser processing. Further, the YAG laser oscillator 5 is provided with a hand-held laser processing head 17 which is separate from the laser processing head 11 provided on the articulated robot 3, and between the laser processing head 17 and the YAG laser oscillator 5 as well. It is connected by an optical fiber 9. Also, this Y on hand
The AG laser processing head 17 is also provided with a CCD camera 13 for observing the surface of the material to be processed.

A known calorimeter 1 for receiving a laser beam from the laser processing head 11 at a fixed position near the table 15 and measuring the laser output thereof.
9 is installed.

The multi-joint robot 3 is controlled by a robot controller 21 having a CNC device (not shown) incorporated therein to cut or weld the workpiece W. This robot controller 21
Is provided with a teaching box 23 for teaching the operation of the articulated robot 3 and a CRT monitor 25A for monitoring an image from the CCD camera 13.

Further, a work table 27 is provided adjacent to the table 15 for temporarily welding the workpiece with the laser processing head 17 in hand, and a CCD camera 13 provided in the laser processing head 17 in hand. There is provided a CRT monitor 25B for monitoring the image from.

The laser processing head 17 on hand has a safety mechanism for protecting the worker from danger.
For example, a detection means (not shown) for detecting that the laser processing head 17 and the workpiece W are in contact is provided,
Except when the detection means detects the contact between the laser processing head 17 and the workpiece W and the operator depresses the foot switch 29 and then presses the laser emission switch (not shown) provided on the laser processing head 17. Has a safety mechanism to prevent the laser light from coming out.

In the above structure, the laser processing head 11 of the articulated robot 3 is moved to the calorimeter 19 every time the laser processing by the articulated robot 3 elapses for a predetermined time.
The laser beam from the laser processing head 11 is moved upward, and the calorimeter 19 is irradiated with the laser beam from the laser processing head 11, and the output of the laser emitted from the laser processing head 11 is measured. At this time, the laser light incident on the light receiving portion of the calorie meter 19 is incident in a defocused state of the laser light so as not to damage the light receiving portion of the calorie meter 19.

As described above, the output of the laser emitted from the laser processing head 11 is measured at regular time intervals. Therefore, if the output that has a great influence on the processing quality in laser processing is lower than the allowable range, the laser is output. It is possible to adjust the output of the oscillator or take appropriate measures immediately, such as cleaning or replacing the optical system. Therefore, for example, it becomes possible to prevent in advance the defect welding due to insufficient penetration which causes no apparent problem in the welding process. The laser processing apparatus 1 according to the present embodiment has been described as a playback type articulated robot, but it is obvious that a general Cartesian laser processing machine can be similarly used.

Now, FIG. 2 shows another embodiment of the laser output detecting method which can be used in the laser processing apparatus 1 and the laser processing head using the detecting method. In FIG. 2, the same parts as those in FIG. 1 are designated by the same reference numerals.

This embodiment will be described below with reference to the drawings. The laser processing head 50 includes a laser processing head main body 51. Inside the laser processing head main body 51, a reflecting mirror 53 that reflects a laser beam and a semi-transparent mirror 55 that transmits visible light and 1% of the laser beam are provided. It is installed. The laser processing head body 5 below the semi-transparent mirror 55
A condenser lens 57 is mounted in the unit 1. Further, below the condenser lens 57, a drawer device 61 having a transmitted light window 59 is provided. This pull-out device 61 operates the push button 63 to move the laser processing head body 5
The laser processing head body 51 is pulled out from the apparatus 1 or set in the laser processing head body 51. A nozzle 65 is detachably provided at the tip (lower end) of the laser processing head body 51.

The laser processing head body 51 (see FIG.
(Upper left side in FIG. 4), a conical cylindrical body 67 is provided. A collimator lens 69 is attached to the lower portion of the tubular body 67, and an optical fiber plug 71 is attached to the upper portion of the tubular body 67.
Is provided. The laser light emitting end of the optical fiber 9 is provided at the end of the optical fiber plug 71, and the other end of the optical fiber 9 is at the YAG laser oscillator 5
Connected to

The laser processing head body 51 (see FIG.
(Upper right side in FIG. 1), a hollow cylinder 73 is provided, and the CCD camera 13 for observing the surface of the work W and a light source 75 for illuminating the surface of the work W are provided in the hollow cylinder 73. There is. The CCD camera 13 is connected to the CRT monitor 25A.

Further, the laser processing head main body 51 on the back side of the semi-transparent mirror 55 receives 1% laser light transmitted through the semi-transparent mirror 55 and measures the laser output thereof. 77 is provided.

With the above structure, the output of the received laser light can be measured by injecting the laser light into the output measuring device 77 every time a predetermined time elapses. The output of the laser light measured in the present embodiment is the output of the laser light immediately before entering the condenser lens 57, but the decrease in the output of the laser light due to only the condenser lens 57 is almost negligible. Since there is no problem in practical use. Further, with such a configuration, the output of the laser light can be measured in the laser processing head. Therefore, when it is applied to the articulated robot 3 or the Cartesian coordinate type laser processing machine, it is installed at a fixed position. It is not necessary to move the processing head to the laser power measuring device.

[0029]

According to the first aspect of the present invention, since the laser output at the processing position, which changes with time due to deterioration of the laser oscillator and the optical system, can be detected at regular time intervals, laser processing is possible. With this, output control at the processing position, which is one of the factors that greatly affects the processing quality, becomes possible, and the processing quality of laser processing becomes stable. As a result, it is possible to prevent in advance, for example, a defect welding due to insufficient penetration which is apparently no problem in the case of welding.

According to the second aspect of the present invention, since the laser output in the vicinity of the processing position, which changes with time due to deterioration of the laser oscillator and the optical system, can be detected at regular time intervals, the laser processing is performed. Quality is stable. In particular, in the case of welding, it is possible to prevent in advance the defect welding due to lack of penetration, which is apparently no problem.

According to the third aspect of the present invention, the laser output in the vicinity of the processing position, which changes with time due to the deterioration of the laser oscillator and the optical system, can be detected at regular time intervals. Quality is stable. Moreover, since the laser output can be detected without moving the laser processing head to the measuring device, the output detection time can be shortened.

[Brief description of drawings]

FIG. 1 is an embodiment of a laser processing apparatus using a laser output detection method of the present invention.

FIG. 2 is another embodiment of the laser output detection method of the present invention and the laser processing head using the detection method.

[Explanation of symbols]

 1 Laser processing device 3 Articulated robot 5 YAG laser oscillator 9 Optical fiber 11 Laser processing head 13 CCD camera 15 Table 19 Calorimeter 25 (A, B) CRT monitor 50 Laser processing head 51 Laser processing head body 53 Reflector 55 Semi-transparent mirror 57 Condensing lens 69 Collimating lens 77 Output measuring instrument

Claims (3)

[Claims] 1. A method for detecting a laser output applied to a workpiece from a laser processing head of the laser processing apparatus, wherein a laser output measuring apparatus is provided at a fixed position near a processing table of the laser processing apparatus, and a predetermined time has elapsed. A laser output detecting method, wherein the laser processing head is moved to an installation position of the laser output measuring device for each time to detect a laser output. 2. A method for detecting a laser output applied to a workpiece from a laser processing head of a laser processing apparatus, wherein a laser output measuring device is provided inside the laser processing head, and is incident on a condenser lens of the laser processing head. A laser output detection method, which comprises detecting a laser output according to the present invention. 3. A laser processing head provided with an optical system comprising two reflecting mirrors for making laser light from a laser light source incident on a condenser lens, wherein the reflector on the optical axis of said condenser lens is a laser. Laser processing characterized by comprising a semi-transparent mirror capable of transmitting a part of light and providing an output measuring device for measuring the output of the part of the laser light transmitted through the semi-transparent mirror inside the laser processing head. head.