JPH042352B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser processing machine that performs welding, cutting, etc. by focusing laser light emitted from a laser oscillator and irradiating it onto a workpiece.

[Conventional technology]

In general, one of the factors that affects the machining ability of a laser beam irradiated onto a workpiece in a laser processing machine is the distribution of laser energy in a laser beam cross section called a transverse mode, as illustrated in FIG. In other words, the energy distribution of the laser beam changes due to the influence of gas components or floating dust in the laser optical path from the emission port of the laser oscillator to the condensing lens via the reflector, as well as due to deterioration of the reflector. It is known that even if the laser beam is in the same transverse mode, the energy distribution of the laser beam focused by the condenser lens changes, significantly reducing the processing ability. In addition, due to the factors mentioned above,
It is also known that the transverse mode itself sometimes changes.

By the way, in the single mode a in Fig. 2, the intensity distribution of the beam energy in the cross section of the laser beam propagation path, that is, the relationship between the relative intensity and the beam diameter, shows a Gaussian distribution characteristic, with the intensity at the center of the beam being the maximum, and the wavefront This is the lowest mode in which the whole body vibrates in the same phase, and is also called the equiphase mode or fundamental mode. The other b, c, d, e, and f multimodes are a combination of multiple beam intensity patterns, and compared to single modes, the energy is dispersed within the cross section, so they are focused by the condenser lens. This results in poor concentration of laser energy.

As mentioned above, the degree of concentration of the laser energy irradiated to the workpiece differs depending on the mode of energy distribution in the cross section of the laser beam, so in order to obtain an appropriate spot of laser beam, it is necessary to periodically We are examining the factors that cause variations in the state of the laser mode in the optical path.

[Problem that the invention seeks to solve]

In conventional laser processing machines such as those mentioned above, if the initially set transverse mode of the laser beam fluctuates, and if the processing capacity for the workpiece is changed due to this, the processing efficiency may decrease or defective products may be produced. There were problems such as the occurrence of

This invention was made to solve this problem, and by detecting and displaying the transverse mode pattern of the laser beam emitted from the oscillator just before it enters the condensing lens, it is possible to always maintain a predetermined The object of the present invention is to obtain a laser processing machine that can perform processing using a laser beam having a transverse mode pattern.

[Means for solving problems]

The laser processing machine according to the present invention propagates a laser beam emitted from a laser oscillator through a reflecting mirror and a condensing lens, and processes the workpiece by irradiating the laser beam with the laser beam in the optical path immediately before the condensing lens. A rotating wire beam mode analyzer that reflects and extracts light by rotating a wire set at a predetermined angle with respect to the optical axis at high speed, and detects the mode pattern, and this rotating wire.・Display means for displaying the mode pattern of the laser light detected by the beam mode analyzer is provided.

[Effect]

In this invention, a wire rotating at high speed in a rotating wire beam mode analyzer reflects and extracts laser light in an optical path just before a condensing lens, and detects the mode pattern. Since the display means displays the mode pattern of the laser light irradiated onto the workpiece, it is possible to grasp the mode pattern of the laser light irradiated onto the workpiece in real time even during processing.

〔Example〕

FIG. 1 is a schematic diagram showing the configuration of a laser processing machine according to an embodiment of the present invention. 1 is a laser oscillator, 2 is a laser beam emitted from the laser oscillator 1,
3 is a reflecting mirror that refracts the laser beam 2, and 4 is a condenser lens that focuses the laser beam 2 and irradiates it onto the workpiece 5. 6 is a rotating wire beam mode analyzer, 6a is a motor that rotates at a constant speed,
6b is a motor shaft directly connected to this motor 6a, 6c
2a is a wire made of a rigid body such as molybdenum (Mo) that rotates around the motor shaft 6b;
7 is a sampling laser beam extracted by reflecting the laser beam 2 on a wire 6c, 7 is a sensor that detects the beam mode from the sampling laser beam 2a, and 8 is a display device that displays the pattern of the beam mode based on the output of the sensor 7. It is.

In the laser processing machine according to the present invention configured as described above, the motor 6a rotates the wire 6c at a high speed of, for example, about 1800 rpm, while controlling a portion (1 to 2%) of the laser beam 2 reflected on the surface of the wire 6c.
The sampled laser beam 2a extracted from the sensor 7
The energy distribution in the cross section of the laser beam 2, that is, the transverse mode, is detected, and the pattern is displayed on the display device 8.

If the transverse mode pattern displayed on the display device 8 fluctuates beyond a predetermined tolerance, the cause of the pattern fluctuation in the laser optical path up to the laser oscillator 1 or the extraction position of the laser beam 2 is traced, and the defective part is located at the beginning. By restoring to the normal state at the time of setting, proper processing is performed while always irradiating the workpiece 5 with the laser beam 2 in a predetermined mode.

In this way, the laser processing machine of the present invention detects the mode pattern of the laser beam just before the condensing lens, so when the present invention is applied to a laser welding machine, for example, it is possible to detect the mode pattern of the laser beam just before the condenser lens. The mode pattern of the irradiated laser light can be grasped in real time even during welding, and it is possible to prevent spatter during welding from affecting mode pattern detection.

〔Effect of the invention〕

As explained above, this invention uses a wire that rotates at high speed in a rotating wire beam mode analyzer to reflect and extract laser light in the optical path just before the condensing lens, and detect the mode pattern. Since the mode pattern is displayed on the display means, the mode pattern of the laser light irradiating the workpiece can be grasped in real time even during processing, making it possible to always irradiate the workpiece with the appropriate mode of laser light. This has the effect of providing good processing quality.

Further, when the present invention is applied to a laser welding machine, it is possible to prevent spatter during welding from affecting mode pattern detection.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the configuration of a laser processing machine according to an embodiment of the present invention, and FIGS. 2 a to 2 f are diagrams showing examples of mode patterns of laser light. In the figure, 1 is a laser oscillator, 2 is a laser beam, 3 is a reflecting mirror, 4 is a condensing lens, 5 is a workpiece,
6 is a rotating wire beam mode analyzer, 6c is a wire, 7 is a sensor, and 8 is a display device.

Claims (1)

[Claims] 1. In a laser processing machine that processes a workpiece by propagating a laser beam emitted from a laser oscillator through a reflecting mirror and a condensing lens, the laser beam in the optical path immediately before the condensing lens A rotating wire beam mode analyzer that reflects and extracts light by rotating a wire set at a predetermined angle with respect to the optical axis at high speed, and detects the mode pattern;・Beam mode・
1. A laser processing machine comprising display means for displaying a mode pattern of laser light detected by an analyzer.