JPS6257791A - Laser beam machine - Google Patents

Abstract

PURPOSE:To optimize the mode of laser light and to improve processing quality by monitoring the mode pattern of the laser light detected just before a condenser lens by using a bead mode analyzer. CONSTITUTION:A wire 6c is swiveled by a motor 6a and part of the laser light 2 reflected to the wire 6c is extracted. The sampled laser light 2a is radiated to a sensor 7 which detects the energy distribution at the section of the laser light 2a, i.e., transverse mode, and displays the pattern thereof on a display device 8. The cause for the defect is traced when the transverse mode pattern fluctuates beyond the prescribed permissible range. A normal state is restored after the cause is eliminated and the processing by the laser light of the prescribed mode is executed. The good processing quality is thus obtd.

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, in laser processing, one of the factors that affects the processing ability of the laser beam irradiated onto the workpiece is the distribution of laser energy in the cross section of the laser beam, that is, the second
An example of this is the so-called transverse mode, which is a distribution mode of laser energy in a cross section as illustrated in the figure. For example, when cutting widths are required to be extremely small, such as in precision cutting, the problem is caused by the deterioration of the concentration of energy caused by the difference in the minute spot diameter of the laser light that is focused by the condenser lens and irradiated onto the workpiece. It is known that this can significantly reduce machining performance.

In Fig. 2, the single mode of (al) is the intensity distribution of the beam energy in the cross section of the laser light propagation path, that is, the relationship between the relative intensity and the beam diameter shows Gacks distribution characteristics, the intensity at the center of the beam is maximum, and the entire wavefront is It is the lowest mode in which oscillates in the same phase, and is also called the equiphase mode or fundamental mode.The other modes (bl, (cl * fdl,
fe+, the multimode of the mountain is a combination of multiple beam intensity patterns, and compared to a single mode, the energy is dispersed within the cross section, so the concentration of laser energy focused by the condenser lens is inferior. .

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 laser beam spot, it is necessary to periodically We are examining the factors that change the behavior 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 the machining ability for the workpiece is changed due to this, the machining efficiency decreases and malfunctions occur. There were problems such as non-defective products being produced.

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 immediately before it enters the condenser lens, it is possible to always maintain a predetermined level. The object of the present invention is to obtain a laser processing machine that can perform processing using a laser beam with a transverse mode pattern.

[Means for solving problems]

A laser beam processing machine according to the present invention extracts a laser beam emitted from a laser oscillator and propagated to a condensing lens via a reflecting mirror by reflecting it on a wire rotating in an optical path just before the condensing lens, and extracts the laser beam in a transverse mode. It detects and displays a pattern.

[Effect]

In this invention, the transverse mode of the laser beam is detected and displayed in the optical path just before the condenser lens, so the mode pattern of the laser beam irradiated onto the workpiece is constantly grasped and processed.

〔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 reflector that refracts the laser beam (2), and (4) is a laser beam (
2) is a condensing lens that focuses and irradiates the workpiece (5).

(6) is a rotating wire beam mode analyzer, (6a) is a motor rotating at a constant speed, (6b) is a motor shaft directly connected to this motor (6a), and (6c) is a rotating wire beam mode analyzer. Molybdenum (MO
), (2a) is the sampling laser beam extracted by the laser beam (2) reflected on the wire (6c), (7) is the sampling laser beam (2a)
), and (8) is a display device that displays the beam mode pattern based on the output of the sensor (7).

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.
) The sampling laser beam (2a), which is a part (1 to 2%) of the laser beam (2) reflected on the surface , i.e. detects the transverse mode and displays the display family f(8)
display the pattern.

If the transverse mode pattern displayed on this display family ff1f (8) K fluctuates beyond a predetermined tolerance range, the cause of the pattern fluctuation in the laser beam path to the laser oscillator (1) or the extraction lid of the laser beam (2) is determined. By tracking and restoring the defective part to the normal state at the time of initial setting, proper processing is performed while always irradiating the workpiece (5) with the laser light (2) in a predetermined mode.

In the above embodiment, an example was explained in which a rotating wire beam mode analyzer was used as a means for extracting the laser beam (2), but the laser beam (2) could also be extracted using a pinhole beam mode analyzer. You can do it like this.

〔Effect of the invention〕

As explained above, this invention is configured to extract a part of the laser light emitted from the laser oscillator and propagated at a position immediately in front of the condenser lens, and display the transverse mode pattern of the laser light. By controlling the mode of laser light based on the displayed mode pattern, the workpiece is always irradiated with laser light in the appropriate mode, resulting in good processing quality.

[Brief explanation of the drawing]

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 generator, (2) is a laser beam, (3) is a reflective casting, (4) is a condenser lens, (5 is a workpiece, (6) is a rotating beam mode, Analyzer, (7) is a sensor, and (8) is a display device. Agent: Patent Attorney Masaru Sato Figure 1

Claims (3)

[Claims] (1) A mirror that reflects the laser light emitted from the laser oscillator;
In a laser processing machine that processes a work by propagating it through a condensing lens and irradiating it onto a workpiece, a means for extracting a laser beam in a laser optical path immediately before the condensing lens and detecting a mode pattern of the extracted laser beam are provided. 1. A laser processing machine, comprising: means for monitoring a mode pattern of laser light at a position immediately in front of the condensing lens. (2) The laser processing machine according to claim 1, wherein the means for detecting and displaying the mode pattern of the laser beam is a rotating wire beam mode analyzer. (3) The laser processing machine according to claim 1, wherein the means for detecting and displaying the mode pattern of the laser beam is a pinhole beam mode analyzer.