JPS62213181A - Co2 gas laser device - Google Patents

Abstract

PURPOSE:To improve the reliability of a discharge section by arranging an electrode so that a negative glow ignition-surface and an anode glow ignition-surface are formed in parallel surfaces orthogonal to the direction of a gas flow and fixing a cathode at the position of the upstream of the gas flow to the negative flow ignition-surface. CONSTITUTION:A pin-shaped slit cathode 6 consisting of an ignition section 6a orthogonal to a gas flow 5 and an electrode support section 6b obliquely extending to the insulating plate 8b side toward the upstream of the gas flow 5 from the ignition section 6a and a cylindrical anode 7 extending in the direction orthogonal to a paper surface are disposed oppositely into a discharge excitation section 2. Since a large number of the split cathodes 6 are arranged in the direction orthogonal to the paper surface, negative glow 13 ignition-surfaces generated in the split cathodes 6 and anode glow 14 ignition-surfaces generated in the anodes 7 are shaped in parallel surfaces orghogonal to the paper surface on the operation of a laser. Anode-cathode distance in the vicinity of the insulating plate 8b are made longer than a section in which glow discharge 12 is generated. The size of the ignition sections 6a and the electrode support sections 6b in the split cathodes 6 is determined so that the ignition sections 6a are kept within a predetermined range at the central section of a discharge space.

Description

[Detailed Description of the Invention] [Objective of the Invention 1 (Field of Industrial Application) The present invention relates to a CO2 gas laser device,
In particular, the present invention relates to improvements in the reliability of the structure of the discharge section.

(Conventional technology) Laser processing allows general processing such as cutting, drilling, welding, and surface hardening, as well as heat treatment, to be performed in a non-contact manner at high speed and with high precision using a single processing device. Factory automation has many excellent features, such as high speed, low impact on the area around the machining point, ability to process metals, non-metals, and composite materials, and no tool wear or flaking. is attracting attention as an elemental technology. Research and development of laser processing equipment and laser processing equipment for performing such laser processing has been progressing in the Meishin industrial field, and processing equipment with relatively low output has been put into practical use since then. For example, it is widely used for processing minute parts such as precision mechanical parts and electronic parts.

On the other hand, in recent years, the laser output of CO2 gas lasers [f] has been significantly increased to improve the usability of the discharge part, which was previously impossible. The device fires 17i.
It has now been put into practical use.

This high output CO2 gas laser! If J3 is in A mushroom, CO
A gas containing two gases is circulated at high speed in a laser wind tunnel by a blower, a glow discharge is generated between a pair of electrodes, and a laser beam is generated by an optical resonator with mirrors placed at both ends. At that time, it is necessary to uniformly and stably ignite a large volume of glow discharge, so the cathode is usually arranged as a large number of bottle-shaped T anodes, which are evenly distributed in space, and each cathode is used to discharge a discharge. This goal is achieved by contacting a stabilizing resistor to limit the current.

Conventional examples of such a CO2 gas laser device are shown in FIGS. 2 and 3.

Figure 2 shows the entire device? This is a schematic cross-sectional view of CO2
A discharge excitation section 2, a heat exchanger 3, and a blower 4 are provided in a laser wind tunnel 1 in which a gas containing gas is sealed.

The discharge excitation unit 2 has a feed rate of approximately 5 seconds per second.
0m111. A high-speed gas flow 5 that has been accelerated to a certain degree is circulated and supplied, and the laser gas that has reached a high temperature in the discharge excitation section 2 is transferred to a heat exchanger 3. After being cooled by , it is accelerated again by the feeder 8a and is sent to the discharge ΩJ origin 2.

FIG. 3 is a sectional view taken along the line 'rj' and shows the internal structure of the discharge excitation section 2. As shown in FIG. As shown in the figure, inside the discharge excitation part 2, there is a bottle-shaped portion vJ consisting of an ignition part 6a extending in the gas flow direction, which is the horizontal direction in the figure, and an electrode support part 6b extending in the vertical direction in the figure.
A cathode 6 and a rod-shaped anode 7 extending in a direction 0 orthogonal to the plane of the paper are arranged to face each other.

A plurality of divided cathodes 6 (three in the figure) are arranged in the direction of the gas flow 5 and in a direction perpendicular to the plane of the paper, and are fixed to the lower insulating plate 8b with a fixture 9 in an airtight state. has been done. Note that 88 in the figure is an upper insulating plate that forms an airtight space for the electric cooling section 2 between it and the lower insulating plate 8b, and both insulating plates 8a and 8b are connected to the wall surface of the laser wind tunnel 1. constitutes a part.

J3 is in the t11?1f excitation section 2 having such a configuration, and during operation, a negative high voltage is applied to the divided cathode 6 from the external high voltage power supply 10 via the discharge stabilizing resistor 11, and the positive t41 !7, glow emission t12 occurs. At this time, there is a negative polarity o −1 on the ignition part 6a of the divided cathode 6.
3, and an anode glow 14 is generated on the anode 7, respectively. The discharge energy of the glow emission 1!12 is given to the gas laser medium and excites the 002 molecules, and laser oscillation occurs due to the action of optical resonators (not shown) fixedly arranged at both ends of the discharge excitation part 2, and a radar light is output. By the way, in the discharge excitation unit 2 having the above-mentioned @ command, during the radar operation, the minute 7;
Attachment of the cathode 6 to the insulating plate 8b poses the problem of heating at the location.

That is, during laser operation, the minute v11i three poles 6 are heated by the ignition of the negative glow 13, and the temperature becomes several tens of degrees Celsius or more even if J3 is at the insulating plate mounting position U. Also, as shown in FIG. 3, there is a point A for fixing the split 113 rod 6 to the insulating plate 8b.

The cathode temperature applied to B is determined by the balance between the heat input injected into the v1 cathode 6, that is, the product of the current value per divided cathode 4f11 and the deλ pole drop voltage, and the cooling fJI due to the gas flow 5. Determined by On the other hand, as shown in Figure 3, the division #
In one pole 6, the electrode support portion 6b has a length dimension. Therefore, in the divided cathode 6 with short electrode support portions 6b/fi,
In addition to reducing the cooling effect of the electrode support part 6b, the distance between the negative glow ignition part and the insulating plate 8b is shortened, increasing heat input, so that the temperature at the surface of the electrode support part 6b becomes higher than that of other cathodes. . That is, in FIG. 3, the temperature at point A is higher than at point 8.

In particular, if discharge instability occurs due to some reason, where the discharge is locally concentrated, the cathode 1 where the discharge is concentrated
The current value flowing through the book is several times higher than during steady operation, so
For example, the temperature at point A instantly reaches 100°C. Also,
When the electrode support part 6b is short, negative glow 13 occurs when discharge is concentrated.
There is also a possibility that the particles may reach the insulating plate 8b. In this way, lI;&
Temperature rises or negative glow 13
When the insulating plate 8b is reached, the insulating plate 8b deteriorates, the airtight seal is broken, and impurities enter the discharge space, causing discharge instability. The deterioration of the insulating plate 8b during such concentrated discharge is also a factor that makes the usage conditions of the insulating plate 8b strict.

Moreover, when the glow discharge current increases, the division shade Vi
The negative glow 13 ignited on the gas flow 5 increases in the opposite direction to the direction of the gas flow 5, so that the minute! ! , 1III3t4i6 and the anode 7, the glow discharge 12 appears to be spatially divided according to each divided cathode, and the power density in the space varies. For this reason, the maximum injected power immediately before discharge contraction occurs is limited to 1-1 at a high power of 195 degrees, resulting in the problem that the overall discharge power density that allows stable discharge is kept low.

Furthermore, since it is necessary to arrange a large number of cathodes in a staggered manner within the discharge space, the resistance to the gas flow 5 increases, which not only increases the load on the blower 4 but also complicates the structure of the discharge section. There was a problem in that a large amount of time was required for manufacturing and maintenance work for the electrodes.

(Problems to be solved by the invention) As explained above, the conventional CO2 gas laser device has
There are problems such as a decrease in the reliability of the discharge section due to overheating of the fixing part between the cathode and the insulating plate, a decrease in the discharge power density that allows stable discharge due to the arrangement of the cathode, and a complicated structure of the rIi electric section. was.

The present invention was proposed in order to solve the above-mentioned problems, and its purpose is to make the discharge section structure (:m'M) to prevent the occurrence of high and low discharge power density. However, this increases the group Ti power and prevents overheating at the fixed part between the cathode and the insulating plate, especially local overheating due to the arrangement structure of the cathode, so as to prevent discharge instability. It is an object of the present invention to provide a CO2 gas laser device.

[Configuration of JP Ming] (Means for solving the f1g problem) The CO2 gas laser device of the present invention is such that the negative glow ignition surface and the anode glow ignition surface are parallel surfaces that intersect with the gas flow direction. This is characterized in that the electrodes are disposed at the negative glow ignition surface, and the cathode is fixed at a position upstream of the gas flow relative to the negative glow ignition surface.

(Function) The CO2 gas laser device of the present invention has the above-described configuration, so that the negative glow ignition surface is perpendicular to the gas flow direction and parallel to the anode glow, so the number of divided F3 poles is smaller than that of the conventional one. 1IljIIi can be significantly reduced and has a remarkable configuration.
i-ization will be realized. Therefore, since the uniformity of the discharge is high and the discharge density can be made uniform, the family ff1ffi power can be greatly improved. Furthermore, the M configuration of the fixed portion of the cathode improves the cold IA effect due to the gas flow and prevents deterioration of the insulating plate.

(Example 11) Hereinafter, one embodiment of the CO2 gas laser Rffi according to the present invention will be specifically described based on FIG.

The overall configuration of the device of the present invention is the same as the configuration shown in FIG. 2, so the explanation thereof will be omitted here, and only the discharge excitation section 2, which is the main part of the invention, will be explained. . Further, in FIG. 1, the RIG corresponding to the prior art shown in FIG. 3 is marked with the same symbol q.

*Configuration of the Embodiment In FIG. 1, the discharge excitation section 2 includes an ignition section 6a extending vertically perpendicular to the gas flow 5, and an insulating plate extending upstream from the ignition section 6a toward the gas flow 5. A bottle-shaped segmented cathode 6 consisting of an electrode support portion 6b extending diagonally toward the side 8b and a rod-shaped positive Ir 17 extending perpendicularly to the plane of the paper are arranged to face each other. A large number of divided cathodes 6 are arranged in a direction perpendicular to the paper surface. Therefore, during laser operation, the negative glow 13 ignition surface generated on the divided cathode 6 and the anode glow 14 ignition surface generated on the anode 7 are parallel planes perpendicular to the plane of the drawing. In addition, the pole distance near the insulating plate 8a (l'!1tii of the divided cathode 6, the distance between the fixed side of the support part 6b and the anode 7) is the ignition of the divided cathode 6 at the point where the glow discharge 12 occurs. The distance between the portion 6a and the anode 7 is 5 better than the distance PIIt). Furthermore, from the flow velocity distribution measurement results in the discharge space, it was confirmed that the flow velocity of the gas flow 5 near the insulating plates 8a and 8b and around the beaten discharge space was slower than the flow velocity of the gas flow 5 in the center of the discharge space. Therefore, the divided cathode 6
One method of the ignition part 6a and the electrode support part 6b is that the ignition part 6a and the electrode support part 6b are
is determined so that it falls within a certain range in the center of the discharge space. In this case, regarding the jurisdiction of the electrode support part 6b,
The cooling effect of the gas flow is also taken into consideration.

The operation of this embodiment having the above structure is as follows.

First, the process during laser operation is no different from the prior art described above. That is, when a square high voltage is applied from the high-voltage power supply 10 to the divided 1121ft6 via the discharge stabilizing resistor 11, a glow discharge 12 is generated between the first arc portion 6a of the divided cathode 6 and [4fi7]. .

The discharge energy at this time is given to the gas ray +j medium, which excites CO2 gas molecules, and the laser oscillation is caused by the light J (not shown) fixedly arranged at both ends of the discharge excitation part 2 (by the oscillator's 0- occurs and the first beam of light is output.

Therefore, in this embodiment, the ignition part 6a of the divided cathode 6 is
and electrode support 1. By setting the dimensions of the '1 section 6b, the 1.1 glow 13 is ignited only in the center of the discharge space, as shown in FIG. Furthermore, the temperature of the portion of the divided electrode 6 fixed to the insulating plate 8b is determined by the sufficient dimensions of the electrode support portion 6b.
Since the rotating section is located upstream of the gas flow 5 with respect to the corners 0-13, the temperature is kept low and there is no fear of overheating. Furthermore, even if discharge concentration occurs, the negative glow 13 will not come into contact with the insulating plate 8b. Therefore, the problem of deterioration of the insulating plate 8b as in the conventional case does not occur, and the reliability of the IIl electric section is improved.

In addition, in this example, due to the arrangement of the divided cathodes, the log glow 13 is generated perpendicular to the direction of the gas 2Q5 and parallel to the anode glow 14, so the uniformity of the discharge is high and the discharge is Significant improvements in power density uniformity have been achieved. Therefore, compared to the conventional configuration, the overall discharge power density that can be injected without causing a local increase in discharge density is significantly improved. Regarding the number of divided shadows ff16, whereas in the conventional staggered electrode configuration, there were multiple stages 1) in five directions of gas flow, in this embodiment,
Only one cathode is provided in the same direction, therefore, υ1 cathode 6
The overall number has decreased significantly compared to before.

This simplifies the electrical input width, reduces fluid resistance loss, and reduces the load on the feeder 8a. Roughly speaking, with the reduction in the number of divided lI2 poles 6,
The number of discharge stabilizing resistors 11 is also reduced, which also contributes to the simplification of the configuration.

[Effects of the Invention] As explained above, according to the present invention, the electrodes are arranged so that the log-glow ignition plane and the g1-pole glow ignition plane are parallel planes perpendicular to the gas flow direction, and For negative glow ignition part,
By configuring the cathode to be fixed at a position upstream of the gas flow, 1'! The CO2 gas relay Ffil! achieves a stable discharge and improves the power density, and has a highly reliable discharge section. iff can be provided.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the main parts of an embodiment of the Co2 gas laser device of the present invention, FIG. 2 is a schematic sectional view showing the entire device of the Co2 gas laser device, and FIG. 3 is a conventional C2 gas laser device.
FIG. 2 is a cross-sectional view showing the main parts of the O2 gas laser device. DESCRIPTION OF SYMBOLS 1...Laser wind tunnel, 2...Discharge excitation part, 3...Heat exchanger, 4...Transmission III valve, 5...Gas flow, 6...
- Divided cathode, 6a... Ignition part, 6b... Electrode support part, 7... Anode, 8a.

Claims (1)

[Claims] Optical resonators are arranged on both sides of a laser wind tunnel in which a pair of electrodes are arranged facing each other, and a circulating gas containing CO_2 gas is circulated at high speed in the wind tunnel to generate a glow discharge, thereby emitting laser light. In the excited CO_2 gas laser device, the cathode and the anode are arranged so that the negative glow ignition surface and the anode glow ignition surface, which are respectively generated during glow discharge, are parallel planes perpendicular to the flow direction of the circulating gas, and CO_ characterized in that the cathode is configured to be fixed in the laser wind tunnel at a position upstream of the flowing gas with respect to the negative glow ignition surface.
2 gas laser device.