JPH058073A - Laser beam machine - Google Patents

Abstract

PURPOSE:To obtain a laser beam machine whose converging point of the laser beam has no deviation from a work and for which the just-focusing is always kept even in the cose of a huge work. CONSTITUTION:On the incoming side of the laser beam of a condensing lens 3 which condenses the laser beam 8 on the work 1, a beam radius stabilizing device 9 which is provided with an operature part 12 whose radius is the same or smaller than the radius of the beam is provided. Defective machining caused by out-of-focus of the laser beam is eliminated since the just-focusing is always maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus for cutting, welding, heat treating, trimming and the like of a work (hereinafter referred to as a work) using a laser beam.

[0002]

2. Description of the Related Art FIG. 8 shows an example of a conventional technique disclosed in Japanese Patent Laid-Open No. 64-87098. Reference numeral 1 is a work, and 2 is a beam converging point of the laser beam collected by the condensing lens 3 at one point, and optimum processing can be performed at this point. 4 is a processing head for attaching the condenser lens 3, 5 is a bend mirror for changing the direction by reflecting the laser beam, 6
Is a variable length beam transmission line, 7 is a laser beam oscillator,
8 is a laser beam. In the figure, (a) is the time when the transmission distance of the laser beam is the shortest during processing of the workpiece, and (b) is the time when it is the longest. D1 is the beam diameter of the laser beam that enters the condenser lens 3 in the case of (a), and D2 is the beam diameter of the laser beam that enters the condenser lens 3 in the case of (b).

Since the conventional laser processing apparatus is constructed as described above, the laser beam 8 is emitted from the laser beam oscillator 7, passes through the beam transmission path 6 and is reflected by the bend mirror 5 to change the direction of the work 1. To be
The laser beam 8 is condensed by the condenser lens 3 attached to the processing head 4, and is converged at the beam condensing point 2. The optimum processing condition is when the beam converging point 2 is on the surface of the work 1 (FIG. 8A), which is called just focus.

[0004]

When the work is enormous in the conventional laser processing apparatus as described above, from the laser beam oscillator 7 to the condenser lens 3 at the shortest distance (a) and the longest distance (b) in FIG. The transmission distance of the laser beam 8 is greatly different. The beam diameter of the laser beam 8 becomes larger as the transmission distance becomes longer due to the influence of the divergence angle. Therefore, in the case of (b), the beam diameter D2 incident on the condenser lens 3 is (a). Beam diameter D
Greater than 1. In general, the distance from the condensing lens 3 to the beam condensing point 2 (hereinafter referred to as the focal length) changes depending on the beam diameter of the laser beam 8 incident on the condensing lens 3, so that the focal length in the case of (b) and (a There is a difference in the focal length in the case of). Therefore, the just focus at the position (a) is out of the just focus at the position (b), which causes a problem that a processing defect occurs.

The present invention has been made in order to solve the above problems, and an object thereof is to obtain a laser processing apparatus which always keeps a just focus regardless of the transmission distance of a laser beam.

Further, the beam diameter stabilizing device used in the apparatus is intended to easily obtain a just focus even when using condensing optical devices having different focal lengths.

Further, the beam diameter stabilizing device used in the apparatus is intended to exhibit stable performance even in a high power laser processing apparatus.

[0008]

A laser processing apparatus according to the present invention comprises a beam diameter stabilizing device having an opening equal to or smaller than the beam diameter on a beam transmission path on the laser beam incident side of a focusing optical device. It is provided.

Further, the beam diameter stabilizing device is provided with a diameter adjusting device capable of adjusting the diameter of the opening.

Further, the beam diameter stabilizing device includes a laser beam reflector for shielding the outer edge of the laser beam,
A cooling device for cooling this is added.

[0011]

In the laser processing apparatus configured as described above, even if the laser beam transmission distance becomes long and the beam diameter becomes large, a portion (outer edge portion of the laser beam) larger than the opening of the beam diameter stabilizing device The beam diameter of the laser beam that is cut just before the focusing optical device and enters the focusing optical device is always constant.

Further, the diameter of the beam entering the focusing optical device can be freely set by adjusting the diameter of the opening.

Further, by forced cooling, heat generation of the beam diameter stabilizing device can be suppressed.

[0014]

【Example】

Example 1. FIG. 1 is a system configuration diagram of a laser processing apparatus according to an embodiment of the present invention. In the figure, 1 to 8 are exactly the same as the above-mentioned conventional device. A beam diameter stabilizing device 9 regulates the beam diameter of the laser beam 8 incident on the condenser lens 3. 2 is a plan view showing the beam diameter stabilizing device, and FIG. 3 is a sectional view taken along line III-III in FIG. In FIGS. 2 and 3, reference numeral 10 denotes a laser beam reflector which reflects the laser beam, and is a highly reflective material of the laser beam (for example, CO
_In the case of ₂ lasers, it is composed of copper or aluminum). Reference numeral 11 is a fitting for attaching the beam diameter stabilizing device to the processing head, 12 is an opening formed in the central portion of the laser beam reflector 10 with a diameter D3, and 9 is a beam diameter stabilizing device having the above configuration. 1A shows the case where the laser beam transmission distance from the laser beam oscillator 7 to the condenser lens 3 is the shortest, and D1 is the beam diameter of the laser beam 8 incident on the condenser lens 3 at this time. . (B) is the case where the laser beam transmission distance is the longest, and D2 is the beam diameter of the laser beam 8 which is about to enter the condenser lens 3 at this time. D3 is the diameter of the opening 12 of the beam diameter stabilizing device 9.

In the laser processing apparatus configured as described above, the beam diameter D1 incident on the condenser lens 3 at the position (a) where the transmission distance of the laser beam is shortest is the smallest. Based on this time, the beam diameter stabilizing device 9 in which the aperture diameter D3 of the opening 12 is the same as the beam diameter D1 is attached to the machining head 4 on the beam transmission path immediately before the condenser lens 3 by the attachment fitting 11. In this state, the processing condition is set to just focus and the processing of the work 1 is started. As the processing progressed, the transmission distance from the laser beam oscillator 7 to the condenser lens 3 became sufficiently long. At the position (b), the beam diameter D2 is larger than the diameter D3 (= D1) of the opening 12 of the beam diameter stabilizing device 9 due to the influence of the divergence angle. Here, when the laser beam 8 passes through the beam diameter stabilizing device 9, the diameter D of the opening 12 initially set is set.
A portion larger than 3 (= D1) (outer edge portion of the laser beam) is cut by the laser beam reflecting plate 10, and the beam diameter incident on the condenser lens 3 is always D1 regardless of the transmission distance. As a result, the focal length of the condenser lens 3 is kept constant and the just focus can be maintained regardless of the change in the transmission distance of the laser beam, so that the work 1 can be processed without problems even if it is huge.

Example 2. Although the opening 12 of the beam diameter stabilizing device 9 is fixed in the first embodiment, the opening 12 can be changed as shown in FIG. That is, 13 is a variable aperture, which adjusts the diameter D3 of the opening 12. 14
Is an aperture drive mechanism that drives the variable aperture 13. In this case, even if condensing lenses having different focal lengths are used, the focal length can be adjusted by giving an optimum incident beam diameter to the lens.

Embodiment 3. Although the beam diameter stabilizing device is naturally air cooled in the above embodiment, it may be forcibly cooled. It is shown in FIGS. FIG. 5 is a plan view showing an example of the beam diameter stabilizing device of this embodiment, FIG. 6 is a sectional view taken along line VI-VI of FIG. 5, and FIG. 7 is a system configuration diagram of this embodiment. In FIGS. 5 to 7, 15 is a mounting hose 11 and a cooling hose 18
Mouth part for attaching, 16 is a laser beam reflector
A cooling liquid passage is formed by making the inside of 10 hollow so that the cooling liquid 19 can circulate, and a cooling unit 17 that circulates and cools the cooling liquid. In this case, even if the beam diameter stabilizing device is used in a high-power laser processing device, it does not generate heat and exhibits stable performance. Further, in the present embodiment, only two bases 15 serving as inlets / outlets for circulating the cooling liquid 19 are provided, but the number of bases 15 is not limited to two, and a plurality of bases may be provided. Further, although the liquid is used as the cooling medium in the present embodiment, the same effect can be expected by using the gas. In this case, in addition to the method of passing the cooling gas through the cooling liquid passage 16, the cooling gas can be blown onto the laser beam reflector 10.

Although a condenser lens is used as the condenser optical device in the above embodiment, it is sufficient if the laser beam can be optically condensed, and for example, a parabolic mirror or the like can be used.

[0019]

Since the present invention is constructed as described above, it has the following effects.

By attaching the beam diameter stabilizing device, the diameter of the beam incident on the condensing optical device is regulated so that the focal length of the condensing optical device becomes constant and the just focus is maintained regardless of the transmission distance of the laser beam. can do.

By making the aperture of the beam diameter stabilizing device variable, it is possible to use a condensing optical device having different focal lengths.
Just focus can be easily set by giving an optimum incident beam diameter to the device and adjusting the focal length.

Since the heat generation is suppressed by forcibly cooling the beam diameter stabilizing device, stable performance is achieved without heat generation even when used in a high-power laser processing device.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a first embodiment of the present invention.

FIG. 2 is a plan view of a main part of FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a plan view of a main part of a second embodiment of the present invention.

FIG. 5 is a plan view showing a main part of a third embodiment of the present invention.

6 is a sectional view taken along line VI-VI in FIG.

FIG. 7 is a system configuration diagram of a third embodiment of the present invention.

FIG. 8 is a system configuration diagram of a conventional laser processing apparatus.

[Explanation of symbols]

1 work 2 beam focusing point 3 condenser lens 4 processing head 5 Bend mirror 6 beam transmission line 7 Laser beam oscillator 8 laser beam 9 Beam diameter stabilization device 10 Laser beam reflector 11 Mounting bracket 12 openings 13 variable aperture 14 Aperture drive mechanism 15 Clasp 16 Coolant passage 17 Cooling unit 18 cooling hose 19 Coolant

Claims (3)

[Claims] 1. A condensing optical device for condensing a laser beam onto a work piece, and an opening provided on the laser beam incident side of the condensing optical device and having a diameter equal to or smaller than the beam diameter on the incident side. Then, a laser processing apparatus is provided, which is provided with a beam diameter stabilizing device that regulates a beam diameter of the laser beam incident on the condensing optical device. 2. The laser processing apparatus according to claim 1, wherein the beam diameter stabilizing device has a diameter adjusting device for adjusting the diameter of the opening. 3. The beam diameter stabilizing device comprises a laser beam reflector for shielding the outer edge of the laser beam and a cooling device for cooling the reflector. Laser processing equipment.