JP2001071169A - Laser beam machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser beam machine to machine a work by irradiating the laser beam to be emitted from a laser beam oscillator in which the laser beam is oscillated on a constantly specified level irrespective of the opening/ closing of an external shutter. SOLUTION: The laser beam machine to machine a work by the laser beam to be emitted from a laser beam oscillator comprises an external shutter 16 to control the opening/closing of the emission of the laser beam, a coupling lens 19 to converge the laser beam in controlling the opening of the external shutter, and a fiber part 20 to introduce the laser beam obtained by the coupling lens and guide the laser beam to the work, and the external shutter 16 is provided with a laser beam transmission plate 15 having the laser beam reflectance equivalent to that of a laser beam incident end face of optical fibers.

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, and more particularly, to a laser processing apparatus that irradiates a workpiece with laser light emitted from a laser oscillator to perform processing.

[0002]

2. Description of the Related Art Conventionally, a laser processing apparatus that performs processing while emitting laser light has basically used a laser processing apparatus having a structure shown in FIG. For example, YAG (Yttrium A
neodymium ion (Nd)
Nd: YAG rods 2 and Nd: YAG rods 3 containing ³⁺ ) as an active substance are provided in tandem, and parallel mirrors are provided at both ends thereof.

One side of this parallel mirror is a total reflection mirror 1 for totally reflecting a YAG laser and a YA with a certain transmittance.
It is composed of a half mirror 4 that transmits the G laser, and the laser oscillates between the total reflection mirror and the half mirror,
A YAG laser is emitted from the half mirror.

During processing, the external shutter 6 is open, and the YAG laser is condensed by the coupling lens 9 and is incident on the optical fiber, guided to a workpiece (not shown), and emitted. (Not shown), the light is focused on the surface of the workpiece, and the workpiece is processed by the energy of the focused YAG laser.

Therefore, conventionally, when adjusting or evaluating the characteristics of a laser oscillator, the Y output from the oscillator is usually used.
Generally, the characteristic value and the like of the AG laser are measured using a power meter or the like.

In introducing laser light into the optical fiber, the optical axis of the coupling optical system and the optical hiber is adjusted, and the laser light is introduced into the optical fiber member. When the YAG laser light is introduced into the optical fiber, the laser light is normally transmitted according to the ratio of the laser output output from the oscillator to the laser output after transmission through the optical fiber (hereinafter referred to as transmittance). It is determined whether it has been introduced.

[0007]

However, when the transmittance is actually measured, the transmittance is actually measured to be higher than the transmittance in consideration of the laser light reflectance of the end face of the optical fiber member which is determined physically.

It is considered that this is because the laser light reflected from the end face of the optical fiber returns to the inside of the oscillator, and the laser oscillation is amplified by the returned light.

Therefore, actually, the output of the laser oscillator before amplification by the return light from the optical fiber is compared with the output of the amplified laser light after transmission through the optical fiber. The reality is that the transmittance is measured (or calculated) apparently high.

As a result, there is a problem that the laser output characteristics must be evaluated without confirming the normal optical fiber transmittance. Immediately after the opening of the external shutter, the laser light is introduced into the optical fiber, and at the same time, the return light from the end face of the optical fiber is returned to the oscillator and the output is amplified, so that the output is temporarily (or momentarily) unstable. There was a problem of becoming.

Therefore, an object of the present invention is to solve the above-mentioned problems of the conventional YAG laser processing apparatus, to accurately grasp the fiber transmittance of the YAG laser, and even to open the laser even when the external shutter is opened. An object of the present invention is to provide a YAG laser processing device in which a laser output oscillated from an oscillator is stable.

[0012]

From the above, the present inventor has set forth the following.
In view of the problems described above, as a result of intensive studies to solve the problems, the conventional problems have been addressed by focusing on the output difference of laser light emitted from the laser oscillator and generated when the external shutter is opened and closed. Further, the present inventors have found a method of eliminating the instability, making it possible to process the laser at a constant laser oscillation level, and accurately grasping the fiber transmittance, and completed the present invention.

That is, the present invention relates to an external shutter for controlling the emission of laser light emitted from a laser oscillator in a laser processing apparatus for irradiating a workpiece with laser light emitted from a laser oscillator. In order to keep the level of the oscillating laser constant without being affected by the opening / closing control, the oscillator side of the external shutter, and before condensing the laser light, By providing a laser transmission plate having the same reflectance as the end face on the introduction side, it is possible to make the oscillation level equal to the laser oscillation level amplified by the return light from the fiber end face during opening control of the external shutter. A laser processing device is provided.

Therefore, in the laser processing apparatus according to the present invention, when the laser beam emitted outside the laser oscillator is controlled to be opened and closed by controlling the opening and closing of the external shutter, even when the external shutter is controlled to be closed, An oscillation level equivalent to that during the opening control can be obtained.

That is, at the time of opening control, a part of the YAG laser introduced into the optical fiber condensed by the coupling lens is reflected by the laser incident end face of the optical fiber and is turned back to the oscillator. The oscillation is amplified.

Therefore, in the present invention, since the external shutter is provided with a transmission plate having the same reflectance as that of the end face of the optical fiber member as described above, the external shutter opening control can be performed even when the external shutter is closed. Since the YAG laser returns to the oscillator at the same level as the return light of the YAG laser light to the oscillator at the time, the laser oscillation level is constant regardless of the opening and closing of the external shutter, and the fiber transmittance can be accurately grasped. It becomes.

Further, it is possible to provide a laser processing apparatus capable of performing laser processing at a stable oscillation level without fluctuation of the laser oscillation level at the time of controlling the opening of the external shutter.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a laser processing apparatus according to the present invention will be further described with reference to FIGS.

Therefore, as shown in FIGS. 1 and 2, a laser transmitting plate 15 having the same laser reflectance as the end face of the fiber member 20 is provided on the oscillator side of the external shutter 16 used for controlling the emission of laser light. . This laser transmission plate 1
5 is provided so as to be always perpendicular to the laser optical axis. The surface of the laser transmission plate 15 is a mechanism that opens and closes simultaneously with the external shutter 16.

Therefore, as described above, the laser transmission plate 1
Since the surface 5 is perpendicular to the laser optical axis and is a mechanism that opens and closes together with the external shutter 16, when the external shutter 16 is controlled to close as shown in FIG. As shown in the figure, the laser beam emitted to the laser beam 15 has the same laser reflectivity as the laser incident end face of the optical fiber, and a part of the laser beam returns to the oscillator, and the other laser beam 18 transmitted through the laser transmission plate 15. Is deflected by the external shutter 16 toward the power meter 17.

FIG. 2 shows a state in which laser processing is actually performed by this laser processing machine. That is, as shown in FIG. 2, the external shutter 16 is under opening control, and as shown in the figure, the YAG laser light condensed by the coupling lens 19 and made incident on the fiber 20 is guided to the workpiece by the optical fiber 20. In addition, a part of the laser turns the coupling lens 19 back to the oscillator corresponding to the laser reflectance of the laser incident end face of the optical fiber, and amplifies the laser oscillation level.

If necessary, when the external shutter is controlled to open, as shown in FIG. 2, if the YAG laser beam is guided to the fiber and then irradiated to the power meter 17, the laser output can be measured.

[0023]

As described above, according to the present invention, the external shutter is provided with a laser transmission plate having a laser reflectance equal to the laser reflectance of the end face of the optical fiber, so that the emission control is performed by controlling the opening and closing of the external shutter. In this case, the fluctuation of the laser oscillation level is eliminated.

As a result, even if the external shutter changes from the closed state to the open state, the laser oscillation level is kept constant, the fluctuation of the laser oscillation level when the external shutter is opened can be suppressed, and stable laser processing can be performed. In addition, it is possible to provide a laser processing apparatus capable of accurately measuring the optical fiber transmittance of a laser.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a configuration in which an external shutter according to the present invention used for emission control of laser light is closed.

FIG. 2 is a conceptual diagram showing a configuration in which an external shutter is opened in FIG.

FIG. 3 is a conceptual diagram showing a configuration in which a conventional external shutter used for laser beam emission control is closed.

[Explanation of symbols]

 1,11 Total reflection mirror 2,3,12,13 Nd: YAG rod 4,14 Half mirror 5,15 Laser transmission plate 6,16 External shutter 7,17 Power meter 8,18 Laser beam 9,19 Coupling lens 10, 20 Optical fiber

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Takahiro Odashima 4-3-1 Sagamihara, Sagamihara-shi, Kanagawa F-Term in NEC Laser Automation Co., Ltd. (Reference) 4E068 CA02 CA17 CD10 CE08 CK01

Claims (4)

[Claims] 1. A laser processing apparatus for laser processing a workpiece with laser light emitted from a laser oscillator, comprising: an openable / closable external shutter for controlling the emission of the laser light; A coupling lens for condensing the laser light, an optical fiber member for introducing the laser light condensed by the coupling lens and guiding the laser light to a workpiece, and a laser transmission provided at a portion of the external shutter A laser processing apparatus, comprising: a laser transmission plate having a laser beam reflectance equal to a laser light introduction side end surface of the optical fiber member. 2. The laser processing apparatus according to claim 1, further comprising a laser transmission plate moving mechanism for moving the laser transmission plate out of a laser beam path when the external shutter is controlled to open. 3. The laser processing apparatus according to claim 1, wherein the laser transmission plate moves while being perpendicular to a laser optical axis. 4. When the external shutter is controlled to be closed, laser light emitted from the laser oscillator is transmitted through the laser transmitting plate, totally reflected by the surface of the external shutter, and polarized toward a power meter. 3. The laser processing apparatus according to claim 1, wherein a laser output is measured.