JPH02270384A - Gas laser device - Google Patents

Abstract

PURPOSE:To absorb pressure pulsations induced by a blower to remove before they propagate to a laser resonator so as to improve a laser beam machining in quality by a method wherein a side hole possessed of a specific area is provided to an air guide section on the gas laser medium feed side of a laser resonator or the air guide section in the range including the side hole is covered with an outer case possessed of a specific crosssectional area. CONSTITUTION:A side hole 8, whose area is 0.5-1.1 times as large as the crosssectional area of a feed duct 6 which feeds a gas laser medium, to a laser resonator from a blower, is board in the feed duct 6, and a resonance box 9 is connected to the feed duct 6 through a connecting duct 91. The resonator box 9 has a crosssectional area twice or more as large as the area of the side hole 8, and the volume of the resonance box 9 is so set as to make a resonant frequency coincident with the basic frequency of pressure pulsations, where the resonant frequency is determined by the volume of the resonance box 9, the area of the side hole 8, the length of the connecting duct 91, and the sonic velocity of the gas laser medium. As the resonant frequency of the resonance box 9 determined by a Helmholtz's resonance principle is coincident with the frequency of the pressure pulsations, the energy of a pressure wave is trapped in the resonant box 9 and not discharged again toward the feed duct 6, so that the pressure pulsations are absorbed by the resonance box 9 before they propagate to the laser resonator 1.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a gas laser device such as a carbon dioxide laser,
In particular, the present invention relates to a gas laser device that improves processing quality by reducing output fluctuations of laser light.

Conventional technology An example of the configuration of a conventional gas laser device is shown in FIG.

The gas laser medium is supplied by the blower 3 to the laser resonator 1 through the supply duct 13, and is excited by discharge from the high voltage power supply 2 to output laser light. The discharge voltage changes. As a result, there is a problem in that the excitation input fluctuates, causing output fluctuations, resulting in increased cut surface roughness during cutting.

Conventionally, as shown in Fig. 3, an orifice 12 was provided in the supply duct 13 on the outlet side of the blower 3;
As shown in Japanese Patent No. 80, a method is used in which a large volume container is attached in series to a piping duct that passes a gas laser medium on the outlet side of a blower.

Problems to be Solved by the Invention When an orifice is provided on a duct, the blowing pressure loss of the gas laser medium at the orifice part is high, so in order to obtain the necessary flow rate, it is necessary to reduce the aperture ratio of the orifice. There was a drawback that pressure pulsation could not be sufficiently removed. Furthermore, when a container is installed in series with the duct, the volume of the container is required to be sufficiently larger than the internal volume of the gas laser device, and the installation of the gas laser device has the drawback that the installation area becomes significantly large. To improve the quality of laser processing by eliminating pressure pulsations generated by a blower and reducing laser light output fluctuations without causing blowing pressure loss of the gas laser medium or increasing the size of the gas laser device. be.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides an air guide section that supplies a gas laser medium from a blower to a laser resonator with a cross-sectional area of O, S to 1. A side hole with an area twice as large as that of the side hole is drilled, and a container having a cross-sectional area at least twice the area of the side hole is attached to the side hole using a connecting portion. The depth of this container and the length of the connecting part connecting the container and the side hole shall be at most 0.25 times the wavelength of the pressure wave inside the gas laser device, and the acoustic Set the resonance frequency to 0.9 to the fundamental frequency of the pressure pulsation generated by the blower.
Make it 1.1 times bigger. As another means, the air guide part within a length range of 0.25 times or less the wavelength of the pressure pulsation including the side hole may be covered with an external container having a cross-sectional area at least twice as large as the cross-sectional area of the air guide part. , the acoustic resonance frequency formed by the side hole and the outer container is set to 0.9 to 1.1 times the fundamental frequency of pressure fluctuation within the gas laser device.

Operation In the configuration of the present invention described above, pressure pulsations propagate as plane waves from the outlet of the blower toward the laser resonator within the air guide section that supplies the gaseous laser medium. Since the propagation characteristics change in the area of the side hole, pressure pulsations are guided out of the air guide section through the side hole and into a container installed outside the side hole. According to the inventor's measurements, the ratio of pressure pulsations exiting from the side holes was maximized when the area of the side holes was set to 0.6 to 1.1 times the cross-sectional area of the wind guide section. On the other hand, when a side hole is provided in a hollow container, due to the Helmholtz resonance phenomenon, sound waves near the resonant frequency determined by the sound velocity inside the container, the volume of the container, and the area of the side hole are confined within the container. According to
By making the ratio almost the same, the pressure pulsating waves entering from the side hole no longer return to the laser resonator. Alternatively, the resonance phenomenon described above can be obtained by attaching a container to the air guide section so as to cover the side hole of the air guide section, and the pressure pulsation can be confined. By absorbing pressure pulsations and preventing them from propagating to the laser resonator as described above, fluctuations in the excitation input of the gas laser medium are suppressed, and fluctuations in laser output are reduced to improve the quality of laser processing.

EXAMPLES Hereinafter, examples of the present invention will be explained with reference to the drawings. FIG. 1 shows the configuration of an embodiment of the present invention. The laser resonator 1 excites a gas laser medium by discharge excitation by a high voltage power supply 2 and outputs laser light. The laser camera camera 1 is connected through a maintenance duct 6 and an exhaust duct 7 to a gas cooler 4 attached to an air outlet 31 of a blower 3 and a gas cooler 6 attached to an intake port 32, respectively. A side hole 8 having an area of 0.5 to 1.1 times the cross-sectional area of the supply duct 6 is formed in the supply duct 6, and a resonance container 9 is connected to it through a connection duct 91.

The cross section of the connecting duct 91 is the same as that of the side hole 8. The length of the connection duct 91 and the depth of the resonance container 9 are
In order to prevent the generation of standing waves of pressure pulsations in the connecting duct 91, the wavelength is set to 0.25 times or less of the pulsation wavelength. The resonance container 9 has a cross-sectional area that is more than twice the area of the side hole 8, and the resonance frequency determined by the volume, the area of the side hole 8, the length of the connecting duct 91, and the sound speed of the gas laser medium is equal to the pressure pulsation. The volume of the resonance container 9 is determined to match the fundamental frequency.

Next, the operation of the embodiment of the present invention will be explained. The pressure pulsations head toward the laser resonator 1 from the blower port 31 of the blower 3 and propagate through the supply duct 6 at a sonic speed determined by the composition of the gaseous laser medium. Since the propagation properties of the pressure pulsating waves in the supply duct 6 change at the side hole 8, they propagate into the resonance vessel e through the side hole 8 which passes into the laser resonator 1. In the resonance container 9, the resonance frequency determined by the Helmholtz resonance principle matches the frequency of the pressure pulsation, so the energy of the pressure wave is trapped in the resonance container 9 due to the resonance principle and is not released again toward the supply duct 6. , the pressure pulsations are absorbed before propagating to the laser resonator 1. As a result, periodic fluctuations in the gas laser medium pressure within the laser resonator 1 are eliminated, so the discharge voltage does not fluctuate and the laser output becomes a constant wave. At this time, since the resonance container 9 is parallel to the supply duct 6, no blowing pressure loss of the gas laser medium passing through the supply duct 6 occurs. Further, since the upper limit of the dimensions of the resonance container 9 determined by the resonance conditions is determined by the wavelength of the pressure pulsation, a container can be added to the duct without increasing the size of the gas laser device. FIG. 2 shows another embodiment of the invention. In the figure, the same or corresponding parts as in FIG. 1 are given the same reference numerals. An external container 1o is attached to cover the side hole 8 of the supply duct 6. As in the example shown in FIG. Preventing it from spreading.

Effects of the Invention As described above, according to the gas laser device of the present invention, the pressure pulsations generated by the blower are absorbed and removed before being propagated to the laser resonator, so that the laser beam due to fluctuations in the excitation conditions of the gas laser medium is absorbed and removed. This has the effect of reducing output fluctuations and improving the quality of laser processing, and does not involve blowing pressure loss of the gas laser medium and does not increase the size of the gas laser device.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the structure of one embodiment of the present invention, FIG. 2 is a block diagram showing the structure of another embodiment, and FIG. 3 is a block diagram showing the structure of a conventional gas laser device. 1... Laser resonator, 2... High voltage power supply, 3... Blower, 4... Gas cooler, 6... Gas Cooler, 6... Supply duct, 7... Exhaust duct, 8... Side hole,
9... Resonance container, 10... External container,
31...Blower air outlet, 32...Blower intake port, 91...Connection duct. Name of agent: Patent attorney Shigetaka Awano and 1 other person 1st
Figure Z Figure 2? 3/3

Claims (4)

[Claims] (1) An excitation unit that excites a gas laser medium, a laser resonator that excites the gas laser medium and extracts laser light, an air blower that blows air through the gas laser medium, a cooler for the gas laser medium, and a gas flow from the air blower to the laser resonator. In a gas laser device comprising an air guide section that guides a laser medium, the gas laser medium supply side air guide section of the laser resonator has a side having an area 0.5 to 1.1 times the cross-sectional area of the air guide section. A gas laser device characterized in that a hole is provided and a container having a cross-sectional area at least twice the area of the side hole is attached to the side hole by a connecting portion. (2) The depth of the container and the length of the connection connecting the container and the side hole are set to 0.2 of the wavelength of the pressure wave in the gas laser device.
5 times or less, and the acoustic resonance frequency formed by the side hole, connection part, and container is set to 0 of the fundamental frequency of pressure fluctuation within the gas laser device.
．． 2. The gas laser device according to claim 1, wherein the laser beam is increased by 9 to 1.1 times. (3) An excitation unit that excites the gas laser medium, a laser resonator that excites the gas laser medium and extracts laser light, an air blower that blows air through the gas laser medium, a cooler for the gas laser medium, and a gas flow from the air blower to the laser resonator. In a gas laser device comprising an air guide section that guides a laser medium, the gas laser medium supply side air guide section of the laser resonator has a side having an area 0.5 to 1.1 times the cross-sectional area of the air guide section. A gas laser device characterized in that a hole is provided, and an air guide portion in a range including the side hole is covered by an external container having a cross-sectional area at least twice as large as the cross-sectional area of the air guide portion. (4) The length of the air guide section covered by the outer container is set to 0.25 times or less than the wavelength of the pressure wave inside the gas laser device, and the acoustic resonance frequency formed by the side hole and the outer container is 4. The gas laser device according to claim 3, wherein the frequency is set to be 0.9 to 1.1 times the fundamental frequency of pressure fluctuation.