JP2743667B2 - Laser processing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

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 capable of detecting the presence or absence of a risk of blow-up.

2. Description of the Related Art Conventionally, as a laser processing machine, a laser oscillator that oscillates a laser beam, a focus head that irradiates a laser beam oscillated from the laser oscillator onto a workpiece, and melting by irradiation of the laser beam There is known an apparatus including a detection unit that detects light having a wavelength different from the wavelength of the laser beam generated from a portion, and a control device that controls the laser oscillator and inputs a detected light amount detected by the detection unit. Have been. In this type of laser processing machine, it is possible to detect the quality of the processing state from the rate of decrease in the amount of detected light after stopping the irradiation of the laser beam to the workpiece (Japanese Patent Laid-Open No. 62-77195). Conversely, the quality of the processing state is detected from the time from the start of laser beam irradiation to the workpiece until the detected light amount is obtained (Japanese Patent Publication No. Sho 60-10837).
Conventionally, there is also known a laser processing machine which detects reflected light of a laser beam during piercing and determines that the piercing has been completed when the reflected light disappears (Japanese Patent Laid-Open No. 2-179377). Gazette).

In the above-mentioned laser beam machine, which detects light having a wavelength different from the wavelength of the laser beam, which is generated from the melted portion by the irradiation of the laser beam, any of the blow-up ( This does not take into account the detection of the danger of the molten material being blown up), nor does it detect the end of the piercing process. In addition, since both stop and start of laser beam irradiation are used as the reference for measurement,
It could not be applied to a continuous irradiation type laser beam machine. The present invention has been made in view of such circumstances, and provides a laser beam machine capable of detecting the presence or absence of a risk of blow-up.

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 onto a workpiece, and an irradiation of the laser beam. A detecting means for detecting light having a wavelength different from the wavelength of the laser beam, which is generated from a melted portion of the laser light, and a control device for controlling the laser oscillator and for inputting a detected light amount detected by the detecting means. In the processing machine, a blow-up expected determination light amount for previously determining the presence or absence of blow-up is given to the control device, and the control device performs blow-up when the detected light amount becomes equal to or more than the blow-up expected determination light amount. It is determined that there is a danger.

According to the above construction, when the risk of blow-up increases due to an increase in the residual amount of the melt, the detected light amount is increased as the residual amount of the melt increases. Become. Therefore, by providing the control device with a blow-up expected determination light amount for determining the presence or absence of blow-up in advance, there is a risk of blow-up if the detected light amount exceeds the blow-up expected determination light amount. Can be determined. Since the detected light amount has a wavelength different from the wavelength of the laser beam, it can be detected even when the workpiece is continuously irradiated with the laser beam. Can also be applied. Furthermore, during piercing, the amount of light detected by the detection means is large until a hole is drilled in the workpiece, and after the hole is drilled in the workpiece, the detection amount is detected by the detection means. The amount of light decreases. Therefore, if the piercing end determination light amount for determining the end of piercing is given to the control device in advance, the detection means provided for detecting blow-up is also used, and the workpiece is pierced at the time of piercing processing. When the detected light amount at the time of irradiating the laser beam with the laser beam becomes equal to or less than the piercing end determination light amount, it can be determined that the piercing has ended.

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 provided with a condenser lens 2 that converges the laser beam L oscillated from the laser oscillator 1. The oscillator 1 is a control device 4
The pulse oscillation is controlled by this. 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 of an optical fiber 7 connected to the optical fiber connector 6 through the optical fiber connector 6 faces the inside of the focus head 3. The other end of the optical fiber 7 faces a photodiode 9 as a detecting means via an optical fiber connector 8, and an electric signal converted by the photodiode 9 is input to the control device 4. . 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. The photodiode 9 receives the light generated by the irradiation of the laser beam L continuously, that is, both when the laser beam L is irradiated with the pulse oscillation and when the laser beam is stopped. At this time, the wavelength of the laser beam is, for example, 10600 nm, and the wavelength of the light generated from the molten portion is about 300 to 900 nm. For example, if the photodiode 9 that can detect the wavelength of 700 nm is used, the laser beam L can be used. Only the light generated from the fused portion can be detected without detection. Next, the control device 4 is provided with a blow-up expected determination light amount A for determining the presence or absence of blow-up and a piercing end determination light amount B for determining the end of piercing in advance. Reference numeral 4 indicates that if the detected light amount detected by the photodiode 9 is equal to or larger than the blow-up expected determination light amount A, there is a risk of blow-up. Further, the control device 4 is configured to, when irradiating the workpiece 5 with the laser beam L at the time of the piercing processing, if the detected light amount detected by the photodiode 9 is equal to or less than the piercing end determination light amount B,
It is determined that the piercing is completed. More specifically, as shown in FIG. 2, at the time of piercing, the control device 4 controls the pulse oscillation of the laser oscillator 1 under conditions suitable for the piercing, and at the same time, detects the amount of light by the photodiode 9. ing. At this time, the control device 4 uses the detected light amount detected by the photodiode 9 as the comparison value for the piercing end determination light amount B. That is, until the piercing is completed and a hole is formed in the workpiece 5,
The detected light amount D at the time of irradiation C of the laser beam L is large,
The light amount exceeds the piercing end determination light amount B.
However, when a hole is formed in the workpiece 5, the detected light amount D at the time of the irradiation C of the laser beam L becomes small and becomes equal to or less than the piercing end determination light amount B. Can be determined. Then, the control device 4 ends the piercing processing by the laser oscillator 1 immediately after determining that the piercing is completed or after confirming the completion of the piercing a plurality of times. On the other hand, as shown in FIG. 3, the control device 4 compares the detected light amount F at the irradiation stop time E in the middle of the irradiation time C, not the irradiation time C of the laser beam L, with respect to the blow-up expected judgment light amount A. Used as a value. That is, normally, at the time of the irradiation stop E in the middle of the time C of the irradiation of the laser beam L, the melt of the workpiece 5 is removed by the assist gas and cooled down. The detected light amount F at E is small and does not exceed the blow-up expected determination light amount A. However, if the removal of the molten portion is incomplete and heat is gradually accumulated, the detected light amount F at the time of the irradiation stop E increases. The control device 4 operates at the time of stopping the irradiation E
When the detected light amount F obtained by the integration exceeds the blow-up expected determination light amount A, the control device 4 determines that there is a risk of blow-up before the blow-up. become. The risk of blow-up can be detected not only at the time of piercing but also at the time of cutting. In the case where the laser oscillator 1 is controlled to be continuously oscillated, the blow-up expected determination light amount is set to be larger than that in the above embodiment, and the detected light amount at the time of irradiation with the laser beam L is compared with the blow-up expected determination light amount. Good. Further, in the above embodiment, the photodiode 9 can detect light having a wavelength different from the wavelength of the laser beam L. However, the photodiode 9 detects light of all wavelengths and detects the wavelength of the laser beam L therefrom. May be used. Further, the end of the optical fiber 7 facing the inside of the focus head 3 may of course be disposed toward the workpiece 5.

As described above, according to the present invention, the danger of blow-up can be determined, and the end of the piercing can be detected by using the detecting means therefor. Can be

[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 whether there is a risk of blow-up.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Laser oscillator 3 ... Focus head 4 ... Control device 5 ... Workpiece 9 ... Photodiode (detection means) A ... Expected blow-up judgment light quantity B ... Piercing end judgment light quantity

 ────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-1-1388082 (JP, A) JP-A-2-179374 (JP, A) JP-A-4-361889 (JP, A) JP-A-6-180 114583 (JP, A) JP-A-6-55283 (JP, A) JP-A-51-127196 (JP, U)

Claims (2)

(57) [Claims] A laser oscillator for oscillating a laser beam;
A focus head that irradiates a laser beam oscillated from the laser oscillator toward a workpiece, and a detection unit that detects light having a wavelength different from the wavelength of the laser beam, which is generated from a melted portion by the irradiation of the laser beam. A control device for controlling the laser oscillator and for inputting the amount of light detected by the detection means. A blow-up prediction determination for determining in advance whether or not blow-up has occurred in the control device. A laser processing machine, wherein a light amount is provided, and the control device determines that there is a risk of blow-up when the detected light amount is equal to or greater than the blow-up expected determination light amount. 2. A piercing end determination light amount for previously determining piercing end is given to the control device,
The control device determines that the piercing is completed when the detected light amount at the time of irradiating the workpiece with the laser beam is equal to or less than the piercing end determination light amount during the piercing process. 2. The laser beam machine according to claim 1.