JPH03226391A - Detecting device for focal position of laser beam machine - Google Patents

Abstract

PURPOSE:To easily detect a quantity of light and to improve the detecting accuracy by detecting a colored spark generated by mixture with gas generating the colored spark by mixture with laser beam in detecting a focal position be a laser beam machine. CONSTITUTION:In order to improve the detecting accuracy of a focal position in machining a work piece 36 through laser beam, gas different from working gas used in laser beam machining, for example, gas mixing with laser beam and generating a colored spark such as nitrogen gas, etc., is mixed with laser beam 32. An electromagnetic valve 15 changes the working gas used in detecting a focal point with the working gas used in laser beam machining and changing is controlled by a numerical controller 12. In this way, since the quantity of light of a colored spark is so constituted that it can be detected, the quantity of light is easy to be detected by a light quantity detecting means 40 and the detecting accuracy is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application J) This invention relates to a laser beam focal position detection device that is necessary when processing a workpiece with a laser processing device.

[Prior Art] Devices for cutting or welding workpieces using laser light are well known. In this type of equipment, the workpiece is often processed by focusing the laser beam on the workpiece, and the work of detecting the focal position of the laser beam is essential as a work before laser processing. It is a lot of work.

By the way, as a method for detecting the focal position of a laser processing device, the technique disclosed in, for example, Japanese Patent Application Laid-Open No. 59-159290 or Japanese Patent Application Laid-Open No. 60-96392 is publicly known.

FIG. 3 explains the conventional technology disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 60-96392. In the figure, (30) is a laser oscillator, and (31) is a laser beam oscillated from the laser oscillator (30). (32), a reflecting mirror (33), a condensing lens (34), and an irradiation nozzle (3) to change the direction.
5) and is a processing head that irradiates the workpiece (36).

Here, the machining head (31) supplies a gas jet (38) from its inlet (37) as a machining auxiliary means, and blows the gas jet toward a focal point set in the workpiece (36).

(39) is a spark generated from the irradiation position of the workpiece (36), which is received by the optical sensor (40) such as a phototransistor placed near the workpiece (36).
) The electrical signal obtained by the workpiece (36)! The information is input to the control unit (42) that drives the X, Y, and Z axis drive table (41), which is fixed at 12 positions, in the direction of the arrow Z. In other words, the maximum heating efficiency is detected, and the maximum light intensity is To detect.

As is clear from the above, the laser beam (32) is emitted from the laser oscillator (30) through the processing head (31) to the workpiece (3).
Go to 6) - When the elbow is pressed, the light signal of the generated spark (39) is converted into an electrical signal, which constantly adjusts the height position of the workpiece (36) and focuses the laser beam (32). , for example on the surface of the workpiece (36).

[Problem to be Solved by the Invention J] The conventional focus position detection device is configured and operates as described above. That is, the conventional device detects the amount of sparks generated by the laser beam (32) and gas jet (38) generated by the workpiece (36) at the time when the amount of spark light is at its highest and the heating efficiency is at its highest. Although the amount of light received by the optical sensor (40) is the highest, there is a problem to be solved that the detection accuracy is poor because the amount of light is small.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a highly accurate focal position detection device for a laser processing device.

[Means for Solving the Problems] A focal position detection device for a laser processing device according to the present invention includes:
a laser beam irradiation means for irradiating the workpiece with a laser beam when detecting a focal position of the laser processing device; and a gas supply means for supplying a gas that is mixed with the laser light irradiated to the workpiece to generate colored sparks. and a light amount detection means for detecting the amount of colored sparks generated by mixing the laser light irradiated from the laser light irradiation means and the gas supplied from the gas supply means.

[Operation 1] In this invention, the amount of colored sparks generated by mixing the laser beam irradiated from the laser beam irradiation means and the gas that generates colored sparks by mixing with the laser beam is detected.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a diagram showing a schematic configuration of a laser processing device, in which a light amount detection means (40) has, for example, a phototransistor (lO) at its tip, and a processing head (31) near an irradiation nozzle (35). Installed. Phototransistor (
The voltage signal of lO) is sent to the NC device f through the amplifier (111).
12) is sent as data.

(13) is a motor (14) that moves the machining head (31) in the direction of arrow Z in the figure in response to a command from the NC device (Ill).
) is a servo amplifier that transmits command signals to the Also,(
15) is a solenoid valve that switches the type of processing gas, and is controlled by the NC device (12).

By the way, in the above embodiment apparatus, the workpiece (36
), the focal point is set to the workpiece (3), for example.
As mentioned above, it is necessary to adjust the surface of A gas that mixes with the light to generate colored sparks is mixed with the laser light. The solenoid valve (15) is used to switch between the gas used during focus detection and the processing gas used during laser processing, and is connected to the NC device (12).
Switching is controlled by

The embodiment device of this invention is configured as described above,
Next, its operation will be explained. In the 11th g, the operator places the irradiation nozzle (35) on the workpiece (36) in advance.
). Next, the operator turns the focus adjustment function to "F" using a switch provided in the NC device (12). FIG. 2 is a flowchart of the focus adjustment operated by the switch. Focus adjustment will be explained according to this flowchart.

First, determine whether the gas being supplied to the workpiece (36) is nitrogen gas by the type of solenoid valve (15) (step Sl), and if it is not nitrogen gas, select the solenoid valve (1511) for nitrogen gas. (Step S2).Next, the workpiece (36) is irradiated with laser light and nitrogen gas is supplied (Step S3).Then, the phototransistor (lO)
The output voltage of the phototransistor (lO) is compared with a reference value set in advance in the NC device (12), and the processing head (31) is turned to zero, for example, until the output voltage of the phototransistor (lO) exceeds the reference value.
．． It is raised at a relatively fast speed of about 5 m/min (steps S4 and S5). When the phototransistor (lO) output voltage exceeds the reference value, the processing head (31) is set to 0.
Every time the process goes up by 01mm, the Z-axis coordinate value of the processing head (31) and the voltage value of the phototransistor (10) at that time are stored in the memory in the NC device (12) (step S).
6, S7), this process is repeated until the voltage value of the phototransistor (lO) becomes below the reference value (step S8).
). When the voltage value of the phototransistor (lO) becomes less than the reference value, the processing head (31) stops rising, and the laser light irradiation and processing gas supply are stopped (step S9). Next is NC outfit! (12) searches for the maximum value of the voltage values in the memory (step 310), and issues a movement command for the processing head (31) so that the corresponding processing head (31) has a two-axis coordinate value of 4° (step 310). ). Finally, when the Z-axis movement is completed (step 512), automatic focus adjustment ends. When the focus adjustment for the workpiece (36) is completed as described above, the primary solenoid valve (1
5) is switched from the solenoid valve (151) to the solenoid valve (152) to perform laser processing on the workpiece (36).

〔Effect of the invention〕

As described above, according to the present invention, when detecting the focal point position of a laser processing device, the amount of light of colored sparks generated by mixing a laser beam and a gas that generates colored sparks by mixing with this laser beam is detected. This has the advantage that the amount of light is easily detected by the light amount detection means, and the detection accuracy is greatly improved.

[Brief explanation of drawings]

FIG. 1 is a partial side cross-sectional configuration diagram illustrating a focus detection device of a laser processing device according to an embodiment of the present invention, FIG. 2 is a flowchart of focus detection of a laser processing device according to an embodiment of the invention, and FIG. The figure is a configuration diagram showing a conventional device. In the figure, (12) is an NC device, and (15) is a solenoid valve. (30) is a laser oscillator, (31) is a processing head, (3
2) is a laser beam, (35) is an irradiation nozzle, (36) is a workpiece, (39) is a spark, and (40) is a light amount detection means. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] In an apparatus that irradiates a workpiece with a laser beam and detects a spark generated at a laser beam irradiation part of the workpiece to detect a focal position of the laser beam, the laser beam irradiates the workpiece with a laser beam and detects a focal position of the laser beam. a laser beam irradiation means for irradiating the workpiece with laser light; a gas supply means for supplying a gas that is mixed with the laser light irradiated to the workpiece to generate colored sparks; 1. A focal position detection device for a laser processing apparatus, comprising: a light amount detection means for detecting the light amount of colored sparks generated by mixing the laser beam and the gas supplied from the gas supply means.