JPS5939492A - Laser working method - Google Patents

Abstract

PURPOSE:To prevent the creater to be generated when melt working ends and to perform laser working with good quality, by defocusing the beam on the surface of the material to be worked when the irradiation of the laser beam is stopped and decreasing gradually the beam output. CONSTITUTION:A laser beam 4 which is released from a laser oscillator 1 provided with an electric power source 2 is irradiated through a total reflection mirror 5 and a condenser lens 6 to the material to be worked 8 on a working table 9 whereby melt working is performed. When said working ends, a driving mechanism 10 is operated by the instruction from a controller 11 to move a working head 7 in the Z-axis direction perpendicular to the material 8 thereby changing continuously and gradually the relative position between the focusing position of the beam 4 by the lens 6 and the surface of the material 8. The power source 2 of the oscillator 1 is then stopped. It is possible to prevent the spreading of the heat affected zone by defocusing, by decreasing continuously the beam output by controlling the power source in the above-mentioned method.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laser processing method that prevents craters from occurring at the end of laser melting processing.

FIG. 1 shows a conventional laser processing device. In the figure (
1) is a controller for controlling the laser output, (
2) is the power supply, (3) is the laser oscillator, (4) is the laser beam, (5) is the total internal reflection that changes the direction of the laser beam (4), (6) is the condensing lens, and (7) is the processing head. , (8
) is a workpiece, and (9) is a processing table that supports and moves the workpiece (8).

Next, the operation will be explained. A laser beam (4) emitted from a laser oscillator (3) is bent by a total internal reflection furnace (5) and is perpendicularly incident on a condenser lens (6). The beam focused by the condenser lens (6) passes through the processing head (7) and is irradiated onto the surface of the workpiece (8). At the same time, a shielding gas is introduced into the processing head (7) and is emitted coaxially with the beam to perform processing. At the end of the irradiation with the laser beam (4), that is, at the end of the laser melting process, the power supply (2) by the controller (11) is activated.
The laser output is gradually lowered by control. Although this has the effect of suppressing the remaining craters to some extent, it has the disadvantage that the laser output becomes unstable near the oscillation darkness value and the craters cannot be completely eliminated.

In order to eliminate the drawbacks of the above, the present invention aims to provide a laser processing device that can gradually and stably lower the beam output by defocusing the beam on the surface of the workpiece at the end of processing. .

An embodiment of the present invention will be described below with reference to the drawings. Second
In the figure, 01 is a drive mechanism that drives a processing head (7) containing a condensing lens (6) along an axis (Z-axis) perpendicular to the workpiece (8) and the processing table (9). The processing head and condensing lens are driven by a pulse motor using a control signal from a 0υ controller. When the melting process is completed, this drive mechanism operates according to instructions from the controller Op, and the distance between the focal position of the laser beam and the surface of the workpiece is gradually changed, and when the power density has decreased sufficiently, the laser beam is finally turned off. The beam is stopped by operating the power source (2).

In the above example, the power intensity is lowered by simply defocusing the beam to treat the crater, but at the same time, the beam cross-sectional area also becomes wider, so the heat-affected zone on the workpiece (8) also becomes wider. There is.

To prevent this, reduce the amount of beam defocus,
At the same time, it is preferable to continuously reduce the beam output in the stabilization region by controlling the power source.

As described above, according to the present invention, the beam intensity can be continuously and stably lowered at the end of laser or other melting processing, and high-quality processing without craters can be achieved. effective.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional laser processing apparatus. FIG. 2 is a block system diagram of a laser processing apparatus according to an embodiment of the present invention. In the figure, (1) is a controller that controls laser output, (2) is a power supply, (3) is a laser oscillator, (4) is a laser beam, (5) is a total reflection mirror, (6) is a condenser lens, (7) is the processing head (8) is the workpiece, (9) is the processing table, Of) is the drive mechanism of the processing head or lens (built-in pulse motor), and 0υ is the control for the drive mechanism of the laser output and processing head, etc. It is a controller that In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Agent Makoto Kuzuno - Engraving of the drawings (no changes to the contents) Figure 1 Figure 2 Procedural amendment (method) Mr. Commissioner of the Japan Patent Office ■, Indication of fact r'i No. 19iil 17457
-149811 No. 2, Title of the invention Laser processing method 3.1 Relationship to the case when doing the mountain
2WF35'j Name (ro, (601):, Ryodenki Co., Ltd. Representative Kata 111 Jinhachibe 4, Agent 11 Address Tokyo, T-dai 111-ku Marunouchi-1'
l + 2 fishing 3 shi] 5. Date of amendment order: 1981
January 80th 6, application subject to amendment ν1, specification, drawings. 7. Contents of the amendment' - Gankichi, specification, and drawings shall be inscribed as attached. (No change in content) That's all

Claims (2)

[Claims] (1) In processing in which a workpiece is irradiated with a laser beam and melted, the relative position of the focus position of the laser beam and the surface of the workpiece is continuously moved when the laser beam irradiation is stopped. Laser processing method. (2) The laser processing method according to claim 1, wherein the laser output is continuously decreased when laser beam irradiation is stopped.