JPS63285988A - Laser oscillator - Google Patents

Abstract

PURPOSE:To prevent laser gas from pulsating and to improve high speed stability by providing a pulsation preventing gas reservoir between a Root's blower and a discharge tube. CONSTITUTION:Laser gas is fed at a high speed by a Root's blower 6 in a discharge tube 1, and cooled by a collar 7 at the output side of the tube 1. A high frequency voltage of the frequency sufficient to cause an electron collection is supplied from an excitation power source 4 to generate a stable laser light 8. In order to prevent the laser gas from pulsating, a gas reservoir 9 is provided between the blower 6 and the tube. Thus, it can prevent the gas from pulsating to stabilize the output of the light. The volume V of the reservoir is given by V = 200 L/r, where L is the step volume of the blower 6 and r is compression ratio. A chamber is divided into three sections by partition plates 13a, 13b, and a pipe 10 for connecting them, and branch pipes 11, 12 are provided. The shape of the entirety can be largely reduced by the inductance effect of the pipes 10 and 11, 12 and the condenser effect of the partitioned chamber.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high-output laser oscillation device for cutting metals and the like, and particularly to a laser oscillation device designed to prevent pulsating flow of laser gas.

[Conventional technology]

Axial flow CO2 lasers are widely used as small, high-power lasers for cutting metals and the like. In particular, axial CO
□Laser has excellent transverse mode characteristics.

FIG. 3 shows the configuration of a conventional axial CO□ laser.

In the figure, ■ is a discharge tube, 2 is a total reflection mirror, and 3 is an output coupling mirror. The laser gas flows through the discharge tube 1 at high speed by a Roots blower 6, and is cooled by a cooler 7 on the output side of the discharge tube 1. Reference numerals 5a and 5b are electrodes provided outside the discharge tube 1, to which a high-frequency voltage having a frequency sufficient to cause an electron trapping phenomenon is supplied from the excitation power source 4. At this time, stable laser light 8 is generated.

[Problem that the invention seeks to solve]

However, axial CO2 lasers may be inferior to orthogonal lasers and low-speed lasers in terms of high-speed output stability. In particular, the surface roughness of machining is worse compared to orthogonal lasers and low-speed lasers.

This high-speed instability is caused by fluctuations in power supply operation, discharge fluctuations, mechanical vibrations in the laser oscillator, etc., but it has been empirically found that the pulsating flow in the Roots blower is a particularly large factor. This is shown in FIG. In the figure, the horizontal axis is time, the vertical axis is laser gas pressure, and the period of the pulsating flow changes depending on the Roots blower used. When the roots blower 6 has two leaves, there is a pulsating flow of about 12% at the frequency of rotation speed x 4, and when the roots blower 6 has three leaves, the frequency is about 12%.
It occurs at a frequency of 6, and the value of pulsating flow is about 8%. Since the output of the laser beam largely depends on the pressure of the laser gas within the discharge tube 1, these pulsating currents naturally have a negative effect on processing.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and provide a laser oscillation device that prevents the i-flow of laser gas.

[Means for Solving the Problems] In order to solve the above problems, the present invention, as shown in FIG. Provided is a laser oscillation device that is characterized in that a gas reservoir (9) having a function of preventing laser gas pulsation is provided between the Roots blower (6) and the discharge tube (1).

[Effect]

The gas reservoir absorbs the pulsating gas flow and stabilizes the output of the laser light.

〔Example〕

An embodiment of the present invention will be described below based on the drawings.

FIG. 1 shows a block diagram of an embodiment of the present invention.

In FIG. 1, l is a discharge tube, 2 is a total reflection mirror, and 3 is an output coupling mirror. The laser gas flows through the discharge tube 1 at high speed by a Roots blower 6, and is cooled by a cooler 7 on the output side of the discharge tube 1. Reference numerals 5a and 5b are electrodes provided outside the discharge tube 1, to which a high-frequency voltage having a frequency sufficient to cause an electron trapping phenomenon is supplied from the excitation power source 4.

At this time, stable laser light 8 is generated. A gas reservoir 9 is added between the Roots blower 6 and the discharge tube to prevent the laser gas from flowing. This prevents pulsating flow of laser gas and stabilizes the output of laser light. It is effective to use the volume V of this gas reservoir given by V=200L/r, where L is the process volume of the Roots blower 6 and r is the compression ratio. for example,
An example of the volume of the gas reservoir when using a three-leaf Roots blower is as follows: Air blowing at 50H2 1 890 m"/H Process volume 0.824 L Compression ratio 1.67 It becomes approximately 100 liters, which is a fairly large capacity gas reservoir. is required.

FIG. 2 shows another configuration of the gas reservoir 9. This reduces the volume compared to the hollow case described above.

In the figure, the chamber is partitioned into three by boundary plates 13a and 13b, and a pipe 10 and branch pipes 11 and 12 are provided to connect each part. These pipes 0
Due to the inductance effect of the branch pipes II and I2 and the capacitor effect of the partitioned chamber, the overall shape can be significantly reduced. When preventing pulsating flow, care must be taken to ensure that the resonance frequency of the gas flow does not match the frequency of the pulsating flow.

In the above embodiment, the gas reservoir is constructed independently, but it is also possible to integrate the gas reservoir and the cooler and omit common parts.

〔Effect of the invention〕

As explained above, in the present invention, a gas reservoir to prevent pulsation is provided between the Roots blower and the discharge tube, which prevents pulsation of the laser gas. High-speed stability can be improved while maintaining the directional mode characteristics.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a configuration diagram of another gas reservoir, Fig. 3 is a block diagram of a conventional axial flow CO□ laser, and Fig. 4 shows a pulsating flow of laser gas. FIG. 1-・・-・--11--Discharge tube 2----------1 total reflection mirror 3--
−−1・−11−−−Output coupling mirror 4−・−・・−・−
- Excitation power supply 6 - Roots blower 9 - Gas reservoir 10 - - - - Connection pipe 11 - -
・−・・・−Branch pipe 12・−・−・−・−
・−・−Branch pipe 13a・・・・・−・−・−Boundary plate 13 b−・−・Boundary plate Patent applicant FANUC Co., Ltd. agent Patent attorney Hattori Sakugan 4th power supply Figure 1 Fig. 2 4 Excited Field Transmission Fig. 3 Fig. 4

Claims (3)

[Claims] (1) A laser oscillation device that conducts laser oscillation by guiding gas discharged from a roots blower to a discharge excitation part, characterized in that a gas reservoir having a function of preventing laser gas pulsation is provided between the roots blower and the discharge excitation part. Laser oscillation device. (2) The laser oscillation device according to claim 1, wherein the gas reservoir has a hollow structure. (3) The laser oscillation device according to claim 1, wherein the gas reservoir is composed of a plurality of chambers separated by a boundary plate and a pipe connecting the chambers.