JP2705485B2 - Laser processing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser beam machine, and more particularly, to a laser beam machine configured to monitor a machining state of a workpiece.

[0002]

2. Description of the Related Art Conventionally, as a laser processing machine, a laser oscillator for oscillating a laser beam, a focus head for irradiating a laser beam oscillated from the laser oscillator to a workpiece, and a laser beam for irradiating the laser beam. Detecting means for detecting light generated from the melted portion of the workpiece, and a control device for controlling the laser oscillator and for inputting a detected light amount detected by the detecting means; 2. Description of the Related Art There is known a configuration in which a processing state of a workpiece can be monitored by a change in light amount. As such an apparatus, for example, Japanese Patent Application Laid-Open No. 62-771
No. 95, JP-A-2-179377, JP-A-4
No. 812286 is known.

[0003]

However, none of the above-mentioned conventional devices has a sensor for detecting whether the function of the detecting means itself is good or not. Therefore, when the function of detecting the light by the detecting means itself is reduced for some reason or when the function becomes defective, there is a disadvantage that the processing state of the workpiece is erroneously grasped. In addition, the above-described conventional apparatus has a drawback that it can detect the end of the piercing process, but cannot detect a cutting failure during the cutting process of the workpiece. The present invention has been made in view of such circumstances, and provides a laser processing machine capable of determining a malfunction of the detection means and determining a cutting failure of a workpiece during cutting.

[0004]

That is, the present invention provides a laser oscillator that oscillates a laser beam, a focus head that irradiates a laser beam oscillated from the laser oscillator toward a workpiece, and a laser device that oscillates the laser beam. Detecting means for detecting light generated from the molten portion of the workpiece by irradiation,
A control device that controls the laser oscillator and receives the detected light amount detected by the detection unit, and monitors a processing state of the workpiece based on a change in the detected light amount detected by the detection unit. In the laser processing machine, a reference light generating means for generating a predetermined amount of reference light and emitting the reference light toward the detection means is provided, and the control device determines in advance that the lower limit is an allowable lower limit. A detection function determination unit that stores the amount of light is provided,
The detection function determination unit provides a laser processing machine that determines that the function of the detection unit is defective when the detected light amount of the reference light actually detected by the detection unit is smaller than a previously stored determination light amount. der Ru.

[0005]

According to this structure, the provision of the reference light generating means and the detecting function determining section makes it possible to easily determine whether the function of the detecting means is normal. Such, as compared with the conventional apparatus has not been determined, it is Ru can <br/> for monitoring processing status of more accurate workpiece.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a pulse oscillation type laser beam machine will be described below.
The laser beam machine includes a laser oscillator 1 that oscillates a laser beam L in a pulse, and a focus head 3 that houses a focusing lens 2 that focuses the laser beam L oscillated from the laser oscillator 1. The oscillation of the oscillator 1 is controlled by a control device 4. The focus head 3 is moved up and down by a lifting mechanism (not shown), and the focus head 3 and a processing table (not shown) on which the workpiece 5 is placed are orthogonal to each other in a horizontal plane by an appropriate driving mechanism. By performing the relative movement in the direction, the workpiece 5 can be subjected to required laser processing.

An optical fiber connector 6 is attached to the focus head 3, and one end 7 a of an optical fiber 7 connected to the optical fiber connector 6 faces the inside of the focus head 3 via the optical fiber connector 6. The other end of the optical fiber 7 is connected to a photodiode 9 via an optical fiber connector 8.
The detection light is converted into an electric signal by the photodiode 9 and input to the control device 4. The two connectors 6 and 8, the optical fiber 7 and the photodiode 9 constitute a detecting means 10. Therefore, the laser beam L from the laser oscillator 1, whose pulse oscillation is controlled by the control device 4, is condensed by the condenser lens 2 of the focus head 3 and irradiates the workpiece 5. Then, the photodiode 9 constituting the detection means 10 receives the light generated by the irradiation of the laser beam L continuously, that is, both during the irradiation of the pulsed laser beam L and during the stop. At this time, the wavelength of the laser beam L is, for example, 10600 nm.
The wavelength of the light L2 generated from the melted portion of the workpiece 5 is about 300 to 900 nm.
If the photodiode 9 that can detect the wavelength of 0 nm is used, only the light L2 generated from the fused portion can be detected without detecting the laser beam L. The light L2 generated from the melted portion of the workpiece 5 has a weak light amount, and the molten light reflected by the condenser lens 2 is transmitted to the end face 7a of the one end 7a of the optical fiber 7 rather than received directly from the workpiece 5. When the light is received obliquely upward toward the condenser lens 2, the amount of detected light increases, and damage due to dust or the like can be prevented.

Next, the control device 4 includes a piercing determination unit 4A for determining that the piercing has been completed, a cutting failure determination unit 4B for determining that a cutting failure has occurred during the cutting of the workpiece 5, and Further, a blow-up determination unit 4C for determining whether there is a risk of occurrence of blow-up during laser processing is provided. In addition, the control device 4 includes a display unit 4D that displays a result of the determination by each of the determination units 4A, 4B, and 4C. Piercing judgment unit 4A
As shown in FIG. 2, a piercing end determination light amount A serving as a reference for determining the end of piercing is stored in advance. Then, the laser beam L is actually applied to the workpiece 5.
When piercing is performed by irradiating the piercing, the detected light amount input from the detection means 10 to the control device 4 is compared with the piercing end determination light amount A. More specifically, at the time of piercing, the control device 4 controls the laser oscillator 1 to perform pulse oscillation under conditions suitable for the piercing, and at the same time, detects the amount of light by the detection means 10. At this time, the control device 4 uses the light amount detected by the photodiode 9 as it is as the comparison value for the piercing end determination light amount A. That is, before the piercing is completed and before the hole is formed in the workpiece 5, the detected light amount C at the time of irradiation B of the laser beam L is large, and exceeds the piercing end determination light amount A. On the other hand, when a piercing hole is formed in the workpiece 5, the piercing hole B
Is smaller than the light amount A for determining the end of the piercing, the piercing determination unit 4A determines that the piercing is completed at this time. If the piercing determination unit 4A determines that the piercing is completed, the display unit 4 indicates that fact.
D, the control device 4 ends the piercing processing by the laser oscillator 1 immediately after it is determined that the piercing is completed, or after confirming the completion of the piercing a plurality of times.

Next, the cutting failure judging section 4 B
The cutting failure determination light amount D for determining that a cutting failure has occurred during the cutting process of the above is stored in advance. Then, the cutting failure judging unit 4B performs the above-described detecting means 10 when actually irradiating the workpiece 5 with the laser beam L to perform the cutting.
Is compared with the detected light quantity D input to the control device 4 from the above and the cutting failure determination light quantity D. That is, as shown in FIG. 3, the controller 4 controls the laser oscillator 1 to perform pulse oscillation under conditions suitable for the cutting process, as in the case of the piercing process, and at the same time, detects the amount of light by the detecting unit 10. doing. Then, when the workpiece 5 is normally cut by the laser beam L during the cutting process, the detected light amount E at the time of irradiation B of the laser beam L is small, and therefore does not exceed the cutting defect determination light amount D. . On the other hand, when the workpiece 5 is not completely cut and the cutting failure occurs, when the laser beam L is irradiated,
In this case, the detected light amount E becomes larger than or equal to the cutting failure determination light amount D, and at that time, the cutting failure determination unit 4B
Are determined to be defective. When the cutting failure is determined by the cutting failure determining unit 4B, the fact is displayed on the display unit 4D, and the controller 4 immediately stops the laser beam irradiation by the laser oscillator 1 after that. Let it.

Next, as shown in FIG. 4, the blow-up judging section 4C sets a blow-up judging light amount F for judging whether or not there is a danger of blow-up in the processing section of the workpiece 5. It is stored in advance. Then, the blow-up determining unit 4C uses the detected light amount H at the irradiation stop time G in the middle of the irradiation time B, not the irradiation time B of the laser beam L, as the comparison value for the blow-up determination light amount F. That is, normally, at the time of the irradiation stop G, which is the middle of the time B of the irradiation of the laser beam L, the melt of the workpiece 5 is removed by the assist gas and cooled. The detected light amount I in G is small and does not exceed the blow-up determination light amount F. On the other hand, if the removal of the molten portion is incomplete and heat is gradually accumulated, the detected light amount I at the irradiation stop time G increases. The blow-up determining unit 4C integrates the detected value at the time of the irradiation stop G, and when the integrated light amount I exceeds the blow-up determining light amount F, the blow-up determining unit 4C Before it is determined that there is a risk of blow-up.
In this case, the display section 4D displays the fact. The risk of blow-up can be detected not only at the time of piercing but also at the time of cutting. In addition, laser oscillator 1
When the laser beam L is continuously oscillated, the blow-up determination light amount F is set to be larger than in the above embodiment, and the detected light amount H and the blow-up determination light amount F at the time of irradiation B of the laser beam L are set.
Should be compared with.

Further, in this embodiment, as shown in FIG.
A reference light generating means 13 for generating a reference light J detectable by the detecting means 10 is provided so that the detecting means 10 can detect the reference light J generated by the reference light generating means 13. At the same time, the control device 4 is provided with a detection function determination unit 4E for determining whether the detection means 10 is functioning normally. More specifically, one end 15a of an optical fiber 15 is attached by an optical fiber connector 14 so as to face the one end 7a of the optical fiber 7 of the detection means 10. This optical fiber 1
The other end of 5 faces the light emitting diode 17 by the optical fiber connector 16. When necessary, the control device 4 generates a reference light J of a predetermined wavelength to the light emitting diode 17.
Is emitted from one end 15a of the optical fiber 15 toward one end 7a of the optical fiber 7 of the detecting means 10. Then, the detection unit 10 inputs the detection light that has detected the reference light J to the control device. On the other hand, the detection function determination unit 4E
0, the detected light amount J ′ of the reference light J actually detected is
The lower limit detection function determination light amount K at which a normal range can be determined is stored in advance. When the detected light amount J 'of the reference light J actually detected by the detection means 10 is smaller than the determination light amount K, the function of the detection means 10 is determined to be defective. At that time,
To that effect, it is displayed on the display unit 4D.

Therefore, in this embodiment, the detecting means 10
It can be easily detected that the one end 7a of the optical fiber 7 constituting the optical fiber 7 is hazy due to dust or the like and the light receiving function is reduced. According to the above-described embodiment, when performing the laser processing on the workpiece 5, it is possible to monitor the processing state from the start of the piercing processing to the end of the required laser processing very well. Moreover, the provision of the reference light generating means 13 and the detection function determining section 4E makes it possible to easily detect even the malfunction of the detection means 10. In the above embodiment, the detecting means 10 detects light having a wavelength different from the wavelength of the laser beam L, but detects light of all wavelengths and removes the wavelength of the laser beam L therefrom. Alternatively, a detection unit that performs the operation may be used. Further, the end 7 a of the optical fiber 7 that faces the inside of the focus head 3 may be disposed toward the workpiece 5.

[0013]

As described above, according to the present invention, it is possible to more accurately monitor the processing state of a workpiece as compared with the conventional apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention.

FIG. 2 is an explanatory diagram for detecting the end of piercing.

FIG. 3 is an explanatory diagram for detecting a cutting failure.

FIG. 4 is an explanatory diagram for detecting whether there is a risk of blow-up.

FIG. 5 is an explanatory diagram for detecting whether the function of a detection unit is good or bad.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Laser oscillator 3 ... Focus head 4 ... Control device 5 ... Workpiece 10 ... Detection means 13 ... Reference light generation means 4B ... Cutting failure determination part 4E ... Detection function determination part D ... Cutting failure determination light amount K ... Detection function determination Light intensity

Claims (2)

(57) [Claims] A laser oscillator for oscillating a laser beam;
A focus head for irradiating a laser beam oscillated from the laser oscillator toward the workpiece, detecting means for detecting light generated from a molten portion of the workpiece by the irradiation of the laser beam, and controlling the laser oscillator And a control device to which the detected light amount detected by the detecting means is input, and a laser processing machine configured to monitor a processing state of the workpiece by a change in the detected light amount detected by the detecting means. A reference light generating unit that generates a predetermined amount of reference light and emits the reference light toward the detection unit, and the control device stores in advance a determination light amount that is an allowable lower limit. A detection function determination unit, wherein the detection function determination unit determines that the detected light amount of the reference light actually detected by the detection unit is smaller than the previously stored determination light amount. If have, laser processing machine, characterized in that the function of the detection means is determined to be defective. To 2. The upper SL controller, prefabricated parts of the workpiece provided a cutting defect determining unit that stores cutting defects amount for determining that a defective cut, the cut defect determination unit, the processed 2. The laser beam machine according to claim 1, wherein when the amount of light detected by the detection means during the cutting of the object is larger than the amount of defective cutting, the workpiece is determined to be defective.