JPS58103992A - External optical apparatus for laser processing machine - Google Patents

Abstract

PURPOSE:To decrease the variation of a laser output and to prevent a lens strain etc. by providing a means for absorbing laser beams between a lens mounting part and an exit hole of laser beams at a nozzle part of an external optical apparatus. CONSTITUTION:A laser absorbing barrel 18 provided with a laser absorbing part 17 painted with a laser absorbing agent 16 is attached between the nozzle 8 fixed at the nozzle mounting part 14 and the lens mounting part 12. Thereby, the laser beams excepting beams which are penetrated the exit hole 9 of the laser beams are reflected to a specified direction at the part 17 and almost all of the laser beams are absorbed due to an effect of the agent 16. Thus, the laser beams impinged to the nozzle 8 are passed through a hole diameter D', are reflected and absorbed at the lense mounting parts 12, 11. Accordingly the force is not so strong to give an effect to cause the strain for a lens 4. A more amount of the laser beams entered a condenser lens 4 can be picked out from the hole 9.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an external optical device that uses a nozzle having a laser beam exit hole smaller than the laser beam diameter in a laser processing machine that performs processing using a laser. Laser processing machines that need to reduce fluctuations in laser output (variations relative to the workpiece, where changes in the laser position relative to the laser beam exit hole affect machining), and laser output from the workpiece or outside of the nozzle Related to optical devices.

First, Figure 1 shows the general principle of use of a laser processing machine. In the figure, 1 is a laser oscillator, 2 is a laser beam, 3 is a total reflection mirror that refracts the laser beam 2, 4 is a condensing lens for condensing the laser beam 2, and 6 is a nozzle for spraying assist gas. , 6 is the focal point of the laser beam, and 7 is the workpiece.

FIG. 2 shows an external optical device for a conventional laser processing machine.

The laser beam 2 is passed through a total reflection mirror 3 to a condensing lens 4.
The laser beam is refracted and irradiated onto the workpiece through the laser beam exit hole/gas exit hole 9 of the nozzle 8. 1o is the gas inlet of the nozzle 8.

Normally, the i-light lens 4 is held between lens mount parts 11 and 12, and is fixed to a nozzle mount part 14 with a screw 13. Further, the nozzle 8 is fixed to the nozzle mount section 14 by a screw 16. This fixing may be performed using a cap nut, a drumstick, etc., instead of the screws 15 as shown in the figure.

If the laser beam 2 is correctly irradiated to the mirror center point and the angle of the total reflection mirror 30 is well adjusted, the laser beam 2 will penetrate from the laser beam exit hole 9 of the nozzle 8 to the workpiece side with an amount almost equal to the input amount. However, normally the total reflection mirror 3 is located at an unknown position. For example, if the total reflection mirror 3 is in the wrong position, the laser beam 2 will not exit from the laser beam exit hole 9 and will be reflected repeatedly within the nozzle 8. However, most of the laser beam power is absorbed by the nozzle 8 and the lens mount section 12. The lens mount section 12 thermally expands due to the laser beam absorbed by the lens mount section 12, giving distortion to the lens 4. The distorted lens 4 deteriorates the laser mode, and the transmission angle of the laser beam after passing through becomes unstable, making laser processing impossible.

To solve this problem, there is a method of attaching a flange to the condensing lens side of the nozzle 8 as shown in Figure 3, or a method of reducing the inner diameter of the nozzle 8 itself in accordance with the direction of the laser beam as shown in Figure 4. . However, in this case, the laser beam is reflected more directly and returns to the laser oscillator itself rather than to the condenser lens 4, reducing the output. This means that the cavity length (distance between the final stage mirror and the output mirror) is
1. This is caused by the fact that some oscillation occurs between the mirror and the nozzle.

The present invention aims to provide an external optical device that can extract more of the laser beam that has entered the condensing lens through the laser beam exit hole at the tip of the nozzle and has less loss.

In other words, even when nearly 100% of the laser beam is reflected within the nozzle, as in the initial adjustment, a laser absorbing cylinder coated with a laser absorbing agent such as carbon paint is provided.
The aim is to obtain stable laser output and optical axis.

FIG. 6 shows an embodiment of the external optical device according to the present invention,
Parts equivalent to those in FIG. 2 are given the same numbers. The nozzle mount section 14, the nozzle 8, and the method of attaching them to each other are the same as those of the conventional device shown in FIG. Attach the I laser absorption tube 1B provided with the I laser absorption tube 1B. As a result, most of the laser beams other than those that penetrated through the laser beam exit hole 9 are reflected and re-reflected repeatedly.
Since the reflection at the laser absorption part 17 is re-reflected in a specific direction (the narrow direction of the tube), in addition to the effect of the laser absorption agent 16,
The entire amount is absorbed. As a result, the laser beam hitting the nozzle 8 passes through the hole diameter D' and is reflected and absorbed by the lens mount portions 12 and 11, so that it cannot become a force sufficient to cause distortion to the lens 4. In addition, in terms of design, the diameter relationship is D (D').

Note that the laser absorption cylinder 18 may be provided with a cooling structure such as air cooling, water cooling, oil cooling, or the like.

The external optical device of the present invention having the above configuration absorbs most of the laser beam reflected by the nozzle, thereby producing a laser beam with enough power to distort the lens that is most susceptible to the effects. The laser beam does not return due to reflection, and even during initial adjustment, fine adjustments can be made over a long period of time regardless of the reflection of the laser beam. Furthermore, it has a very simple structure mechanically and can be supplied at low cost.

Furthermore, additional modifications can be easily made to devices that are already on the market, making them highly practical.

[Brief explanation of the drawing]

Fig. 1 is a front view showing a schematic configuration of a laser processing machine, Fig. 2 is a cross-sectional front view of a conventional external optical device for a laser processing machine, Figs. 3 and 4 are schematic cross-sectional front views of a conventional nozzle, FIG. 6 is a cross-sectional front view of an embodiment of the external optical device for a laser cutting machine according to the present invention. 1... Laser oscillator, 2... Laser beam, 4... Condensing lens, 7... Workpiece, 8... Nozzle , 9... Laser beam exit hole, 11, 12... Lens mount) L
13... Screw, 14... Nozzle mount part, 16... Screw, 16... Laser absorbent, 17... Laser absorbing part, 18...
・Laser absorption tube. Fig. 1 Fig. 2 Fig. 3 WIJ Fig. 4 Fig. 5 Procedural amendment June 2, 1980, to the Commissioner of the Japanese Patent Office 1986 Patent Application No. 203911, Title of Invention: External optics for laser processing machine Relationship with the device 3 amendment person case Patent application Appointment Location 1006 Kadoma, Kadoma City, Osaka Prefecture Name
(582) Matsushita Electric Industrial Co., Ltd. Representative Yama
Toshihiko Shimo 4 Agent 571 Address 1006 Oaza Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Column 6 for a brief explanation of the drawings in the specification subject to the amendment, page 6, 13 of the statement of contents of the amendment We will correct "Laser external processing machine" in the row to "Laser processing machine".

Claims (1)

[Claims] A nozzle mount part, a lens mount part mounted with a condensing lens for condensing a laser beam of a laser processing machine attached to the nozzle mount part, and a workpiece attached to the nozzle mount part. 1. An external optical device for a laser processing machine, comprising: a nozzle for guiding assist dregs; and a laser absorption device provided between the lens mount section and a laser beam exit hole of the nozzle.