JPH0437174A - Laser oscillator - Google Patents

Abstract

PURPOSE:To stabilize the output of laser, reduce the ripple percentage of discharge current, lower the roughness of processing surface and hence improve the quality of processing surface by enlarging the inner diameter of a discharge start auxiliary pipe on a cut-off side end compared with an inner diameter of the pipe on a mounting side end connected with an anode or a cathode. CONSTITUTION:A discharge start auxiliary pipe 20a is connected with an anode 2a. A spacer 11 mechanically holds the end of the discharge start auxiliary pipe 20a on a cut-off side so that its cut-of side end may be concentric to a discharge start pipe body 12a. The ration (a/b) of the inner diameter 'a' of the discharge start auxiliary pipe 20a on the cut-off side to the inner diameter 'b' of the auxiliary pipe 20a on the side connected with the anode 2a or the cathode 3a is arranged to exceed 1.05.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a laser oscillator that generates laser light for cutting, welding, heat treatment, and the like.

2. Description of the Related Art The structure of a conventional laser oscillator of this type will be described with reference to FIG. In the discharge tube group 1 consisting of one or more discharge tubes, a positive 1i 21L is provided for each discharge tube.

In the example shown in FIG. 4, two sets of discharge tubes are formed, and the two sets of discharge tubes are arranged symmetrically to form discharge tube group 1. are formed, and power is supplied from the high voltage power supply 4 to each discharge tube. Further, an output mirror 6 and an end mirror 6 are arranged at both ends of the discharge tube group 1 to form an optical resonator. Further, the vicinity of the cathode electrodes 3m and 3b at both ends of the discharge tube group 1 and the anode electrodes 2a and 2b at the center are connected by a substantially E-shaped circulation tube body 7 to form a gas circulation path. 7 is provided with a blower 8 for circulating gas and a plurality of heat exchangers 9 for cooling the gas. Further, a discharge starting auxiliary tube 10a is provided on the outer periphery of the discharge tube.

1ob is provided, and is electrically connected to the anode 21L + 2b or the cathode 3m, 3b.

Next, FIG. 6 shows an enlarged view of the discharge tube section on the right side.

As is clear from FIG. 5, the discharge tube is equipped with a set of discharge electrodes consisting of an anode 21L and a cathode 3m, which are connected by a discharge tube body 121L to form a discharge section. Further, on the outer periphery of the discharge tube, a discharge starting auxiliary tube 1o&, in which the inner diameter of the end connected to the anode 2& or the cathode 3a and the inner diameter of the cut-off side end are equal, is arranged so as to be electrically connected to the anode i2a or the cathode 3&. ing. The discharge tube section on the left side is configured symmetrically with the discharge tube section on the right side.

In a laser oscillator configured in this way, the gas flow direction, the discharge direction, and the laser beam oscillation axis are coaxial, so when viewed from the optical axis direction, the discharge and the gain distribution formed by the discharge are concentric. It has good symmetry. Therefore, it is said that the machining performance is good when machining is performed using the output laser light.

Problem to be Solved by the Invention However, when a high voltage is applied to the discharge tube, due to the influence of the electric field created by the cut-off side light end of the discharge starting auxiliary tube, the central part of the discharge area at the cut-off side light end of the discharge starting auxiliary tube is There were problems in that continuous large slimmers were formed, discharge current ripple increased, laser output fluctuation became sharper, machined surface roughness increased, and machining quality deteriorated.

Means for Solving the Problems In order to solve the above problems, the present invention provides a discharge starting auxiliary tube which is attached to the outside of the discharge tube body between the anode and the cathode and is electrically connected to the anode or the cathode. The inner diameter of the free-cut side end is made larger than the inner diameter of the side end with the attachment connected to the anode or cathode.

By having the working discharge starting auxiliary tube with the above structure, the influence of the electric field created by the cut-off side optical end of the discharge starting auxiliary tube is reduced, the formation of continuous nutrimers in the center of the discharge area is suppressed, and the laser output is reduced. is stabilized, the discharge current ripple rate is reduced, the machined surface roughness is reduced, and the machined surface quality is improved.

Embodiment Hereinafter, an embodiment of the present invention will be described using FIG. 1, parts that are the same as those in FIG. 5 of the conventional example will be given the same numbers, detailed explanations will be omitted, and differences will be explained. FIG. 1 shows an embodiment of the present invention, showing a longitudinal cross section of a discharge tube section on the right side of a laser oscillator. As is clear from a comparison with FIG. 5, which shows the same parts of the conventional example, in the present invention, the discharge starting auxiliary tube 2
01L, the inner diameter a of the cut-off side end is the anode 2IL.
The structure is such that the inner diameter of the connecting end is larger than the inner diameter of the connecting end. In Figure 1, the discharge starting auxiliary tube 20 & is anode 2m.
is connected to the cathode 3! Even if it is connected to the L side, the effects of the present invention are the same. Although FIG. 1 only shows the discharge tube section on the right side, the discharge tube section on the left side is configured symmetrically with the right side, and the effects of the present invention are the same as those on the right side.

In FIG. 1, reference numeral 11 denotes a stopper that mechanically holds the open end of the discharge starting auxiliary tube 20a so that the open end of the discharge starting auxiliary tube 20& is concentric with the discharge tube body 12a. It is a spacer.

FIG. 2 shows the relationship between the ratio a/b of the inner diameter a of the open end of the discharge starting auxiliary tube 20a to the inner diameter of the positive % 2 a or the inner diameter of the connected end to the cathode 3a and the discharge current ripple rate. Second
As is clear from the figure, when the value of a/b exceeds 1.05, the discharge current ripple rate decreases rapidly. On the other hand, FIG. 3 shows the relationship between the discharge current ripple rate and the machined surface roughness, and shows that as the discharge current ripple rate increases, the machined surface roughness increases and the machining quality deteriorates. Therefore, from FIGS. 2 and 3, the inner diameter a of the cut-off side end of the discharge starting auxiliary tube is made larger than the inner diameter of the end of the discharge starting auxiliary tube connected to the anode or cathode, and a / b. It is clear that by increasing the value more than 1.05, the discharge current ripple rate decreases, the machined surface roughness decreases, and the machined surface quality improves.

In addition, the discharge current ripple rate is It is expressed as

Effects of the invention As is clear from the above explanation, the cutting of the discharge starting auxiliary tube υ
By making the ratio of the inner diameter of the free side end and the inner diameter of the connected end of the discharge auxiliary tube to the anode or cathode larger than 1.05, formation of a continuous streamer in the center of the discharge area is suppressed, and the laser It is possible to stabilize the output, reduce the discharge current ripple rate, reduce the roughness of the machined surface, and improve the quality of the machined surface.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view of a main part of a laser oscillator showing an embodiment of the present invention, and Fig. 2 is a ratio of the inner diameter of the cut-off side end of the discharge starting auxiliary tube to the inner diameter of the connected end to the anode or cathode. Figure 3 is a graph showing the relationship between discharge current ripple rate and machined surface roughness, Figure 4 is an overall configuration diagram of a conventional laser oscillator, and Figure 6 is a graph showing the relationship between discharge current ripple rate and machined surface roughness. FIG. 3 is a vertical cross-sectional view of the main parts of the laser oscillator. 1... Discharge tube group, 2a, 2b... Anode, 31L. 3b...Cathode, 4...High voltage power supply, 5
...Output mirror, 6...Terminal mirror, 7
...Circulation tube, 8...Blower, 9...
...Heat exchanger, 10a, 10b. 201L...Discharge starting auxiliary tube, 11...
・Spacer, 12al12b...discharge tube tube body. Name of agent: Patent attorney Shigetaka Awano 1 barrel
1 Figure Shoulder Public Discharge Tube Emission IIl Related V 悴葺合 Supplementary Force Tube Figure 2 (1> 1.05b Figure a 2 Discharge Current Ripple C%) Discharge Tube Group P1% Majestic Polar Breath Voltage Electric Induction FfA

Claims (2)

[Claims] (1) A discharge tube group consisting of one or more discharge tubes having at least one pair of discharge electrodes consisting of an anode and a cathode, a mirror for laser resonance disposed at both ends of this discharge tube group, and a It consists of a circulation tube connected to the discharge tube group in the vicinity and forming a gas circulation path together with the discharge tube group, and a blower that circulates gas as a laser medium in the gas circulation path, and electrically connected to the anode or cathode. A connected discharge starting auxiliary tube, which has an inner diameter at the open end that is larger than the inner diameter at the end connected to the anode or cathode, on the outer periphery of the discharge tube between the anode and the cathode. laser oscillator. (2) The laser oscillator according to claim (1), wherein the ratio of the inner diameter of the cut-off side end of the discharge starting auxiliary tube to the inner diameter of the connecting side end of the discharge starting auxiliary tube to the anode or cathode is greater than 1.05. .