JP2001287039A - Plasma torch - Google Patents

Abstract

(57) [Summary] To extend the life of a nozzle member constituting a plasma torch and narrow down a plasma arc. A plasma torch has an electrode, a nozzle member disposed to face the electrode, and a plasma chamber formed between the electrode and the nozzle member. You. The nozzle member 2 uses copper or a copper alloy as the base material 17a,
Some or all of the injection holes 2a through which the plasma arc passes are made of a material (carbon or ceramic) having a higher melting point than the base material 17a or a material having high thermal conductivity (silver or silver alloy).
Formed by

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention prevents a plasma gas, which has been plasmatized, from being damaged by heat when passing through an injection hole, prolongs the life of a nozzle member, and reduces the thickness of a plate gas. It relates to a plasma torch that can be squeezed.

[0002]

2. Description of the Related Art Plasma gas which is turned into plasma toward a workpiece (hereinafter referred to as "pilot arc or plasma arc").
The plasma processing method of performing processing such as cutting, welding, or thermal spraying by spraying the same is widely used. In such a plasma torch for performing plasma processing, a pilot arc formed between an electrode attached to the plasma torch and a nozzle member arranged opposite to the electrode is injected from the plasma torch toward a workpiece. A transfer type plasma torch that discharges between the electrode and the workpiece when the pilot arc comes into contact with the workpiece to form a plasma arc, and performs a desired processing by the plasma arc; and an electrode and a nozzle member. There is a non-transfer type plasma torch that forms a plasma arc between them and injects it from the plasma torch toward the workpiece, and performs the intended processing with this plasma arc. It is selectively used as appropriate depending on conditions such as the size of the material.

When a workpiece is processed by a plasma arc, fine and good processing can be performed by narrowing the plasma arc. Pilot arc and plasma arc in the transfer type plasma torch,
Each of the plasma arcs in the non-transfer type plasma torch is injected to the outside through an injection hole formed in the center of the nozzle member. At this time, since the nozzle member is cooled by a cooling fluid such as cooling water or cooling air, the plasma arc passing through the injection hole can be narrowed down by the thermal pinch effect.

[0004]

In the plasma torch constructed as described above, the pilot arc and the injection hole of the nozzle member through which the plasma arc passes have a pilot arc whose inner surface is always at a high temperature of about 30,000 ° C. , Will be exposed to the plasma arc. As described above, there is a problem that the use conditions of the nozzle member are severe and the life is short.
In particular, even if the diameter of the injection hole is reduced for the purpose of narrowing down the pilot arc or plasma arc for precise processing, the pilot arc or plasma arc contacts the inner peripheral surface of the injection hole and is damaged. This has its limitations.

An object of the present invention is to dispose a material having a high melting point and a high thermal conductivity around an injection hole of a nozzle member to extend the life of the nozzle member and reduce the pilot arc and the plasma arc. It is to provide a plasma torch.

[0006]

In order to solve the above-mentioned problems, a plasma torch according to the present invention has an electrode mounted on an electrode base having conductivity, and an electrode disposed opposite to the electrode and having conductivity. A plasma chamber formed between the electrode and the nozzle member, wherein the plasma gas supplied to the plasma chamber and turned into plasma is supplied to the outside from an injection hole of the nozzle member. A plasma torch for processing a workpiece by spraying,
The nozzle member is formed by using copper or a copper alloy as a base material and forming a part or all of the injection holes with a material having a higher melting point or a higher thermal conductivity than the base material.

In the above-mentioned plasma torch, when the plasma gas supplied to the plasma chamber is turned into plasma and injected from the injection hole of the nozzle member, the periphery of the injection hole has a high melting point or high thermal conductivity. In order to reduce the diameter of the injection hole, the diameter of the injection hole is reduced so that even if the plasma arc comes into contact with the inner peripheral surface of the injection hole, it is not easily melted. Therefore, the life of the nozzle member can be extended and the plasma arc can be narrowed down.

In addition, when heat of a pilot arc or a plasma arc (hereinafter, typically referred to as a “plasma arc”) composed of a plasma gas that passes through an injection hole is transmitted to a nozzle member, the heat is quickly transmitted to the nozzle member. It can be transferred to the substrate and cooled. That is, it is possible to narrow the plasma arc passing through the injection hole more finely by the thermal pinch effect.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the above-mentioned plasma torch will be described below with reference to the drawings. FIG. 1 is a sectional view illustrating the configuration of the plasma torch. FIG. 2 shows the first
FIG. 4 is a cross-sectional view illustrating a configuration of a nozzle member according to an example. FIG. 3 is a sectional view showing the configuration of the nozzle member according to the second embodiment.

The plasma torch A shown in FIG. 1 is configured as a transfer type plasma torch, and includes an electrode 1 and a nozzle member 2.
To form a pilot arc, and the formed pilot arc is injected into the injection hole 2a of the nozzle member 2 and the second
When the pilot arc is injected from the injection hole 3a of the nozzle member 3 and comes into contact with a workpiece (not shown) arranged opposite to the plasma torch A, a current is applied between the electrode 1 and the workpiece and a main arc is generated. Is formed, and at the same time, the current between the electrode 1 and the nozzle member 2 is stopped to stop the pilot arc, so that the target material is processed by the main arc. In particular, the plasma torch A is configured as a cutting torch for cutting a workpiece by using an oxygen gas as a plasma gas and supplying the oxygen gas around the electrode 1 to generate plasma.

In FIG. 1, an electrode 1 is formed by burying an electrode material 1a made of hafnium or zirconium at substantially the center of an electrode material holder made of copper or a copper alloy, and has a conductive electrode base. 4 is removably mounted via a screw 5. The electrode base 4 is formed as a cylindrical member having conductivity, and is fixed to the main body 6 of the plasma torch A. A cooling pipe 7 for supplying cooling water is provided inside the electrode base 4, and the cooling water supplied from the cooling pipe 7 contacts the back surface 1 b of the electrode 1 and
Is cooled, and then guided to a passage 8 for cooling the nozzle member 2 through a passage 8 formed between the cooling pipe 6 and the electrode base 4, and then discharged to the outside of the plasma torch A.

A centering stone 9 having an insulating property is arranged on the outer periphery of the electrode 1, and an insulating material 10 having an insulating property is also arranged on the outer periphery of the electrode base 4, and the insulating material 10 is mounted on the main body 6. . A flow passage 11 through which the plasma gas flows is formed between the electrode base 4 and the insulating material 10, and the plasma gas flowing through the flow passage 11 is supplied to the plasma chamber 14 through a hole 9a formed in the centering stone 9. You.

At the tip of the centering stone 9, a nozzle member 2 configured as described later is arranged, and the centering stone 9 is fitted inside the nozzle member 2 so that they are in contact with each other. In addition, the nozzle member 2 is fitted to a cup-shaped mounting member 12, and the mounting member 12 is screwed into a screw portion 13 a formed on an outer peripheral portion of the nozzle base 13, thereby connecting the nozzle member 2 to the nozzle base 13. It is configured such that it can be fitted by being fitted into a depression 13b formed at the tip. Also mounting member 12
With the mounting of the nozzle member 2 on the nozzle table 13 by the above, the centering stone 9 contacting the nozzle member 2 can be mounted between the electrode 1 and the nozzle table 13.

By attaching the nozzle member 2 and the mounting member 12 to the nozzle table 13, a cooling water passage 8 is formed by these members, and the cooling water flowing through the passage 8 is supplied to the body of the nozzle member 2. Heat is exchanged by contacting the nozzle member 2b, whereby the nozzle member 2 is cooled. The electrode 1, the nozzle member 2, and the centering stone 9 constitute a plasma chamber 14.

A second nozzle member 3 is provided on the outer periphery of the nozzle member 2, and the nozzle member 3 is attached to the main body 6 by a cap 15. A secondary gas flow chamber 16 is formed by the nozzle member 2 and the second nozzle member 3, a preset gas containing oxygen gas is supplied to the secondary gas flow chamber 16, and a second nozzle is provided along the plasma arc. It is injected outward from the hole 3a of the member 3.

The nozzle member 2 uses copper or a copper alloy as the base material 17a, and a material having a higher melting point or higher thermal conductivity than the base material is inserted into a part or the front of the injection hole 2a. It is arranged as a material 17b. That is, the first shown in FIG.
In the nozzle member 2 of the embodiment, the copper part 2b
Is formed, and an insert 17 made of a high melting point or high heat conductive material is formed over the entire length of the injection hole 2a.
b is arranged. In the nozzle member 2 of the second embodiment shown in FIG. 3, an insert 17b is arranged on the outlet side of the injection hole 2a.

The insert 17b may be any material as long as it has a higher melting point than the base material 17a made of copper or a copper alloy such as tough pitch copper or has excellent thermal conductivity. For example, as a material having a melting point higher than that of the base material 17a, carbon, ceramic, or a ceramic material is mixed with graphite to form,
There are sintered ones, etc. (If there are others that can be illustrated, please describe them). As a material having higher thermal conductivity than the base material 17a, there is silver or a silver alloy (other materials should be described if they can be exemplified).

The insert 17b is integrated with the base 17a by brazing or press fitting. Whether to braze or press-fit is set according to conditions such as hardness and properties of the insert 17b. For example, carbon and ceramic are preferably integrated into the base material 17a by brazing, and silver or silver alloy is preferably integrated into the base material 17a by press-fitting.

When the nozzle member 2 is manufactured, the substrate 17
a and the insert 17b are each manufactured in advance in the shape and dimensions set for the target nozzle member 2, and then the base material 17a
It is possible to integrate or insert the insert 17b by brazing or press-fitting. Further, it is possible to integrate the base material 17a and the insert material 17b by brazing or press-fitting them in a state where they are roughly processed, and then to finish them by means such as cutting. Regardless of which method is used, the finished shape and dimensions of the nozzle member 2 are the same, and the nozzle member 2 can be stably mounted on the nozzle table 13.

In the nozzle member 2 configured as described above, when a material having a high melting point such as carbon or ceramic is arranged around the injection hole 2a, the material is not easily melted. Damage due to the plasma arc passing through the hole 2a is reduced, and the life of the nozzle member can be extended. For this reason, when the diameter of the injection hole 2a is reduced for the purpose of narrowing the diameter of the plasma arc, even when the plasma arc passing through the injection hole 2a comes into contact with a material disposed around the injection hole 2a, the injection is performed. The hole 2a is not melted, and as a result, a narrowed down plasma arc can be obtained.

When a material having high thermal conductivity such as silver or silver alloy is arranged around the injection hole 2a,
The heat transmitted by radiation or conduction when the plasma arc passes through a can be quickly transmitted to the base material 17a for cooling. That is, it is possible to quickly cool the plasma arc. Therefore, a high thermal pinch effect can be exhibited, and a narrowed plasma arc can be obtained.

In the plasma torch A configured as described above, a pilot arc is formed by the supplied oxygen gas by supplying oxygen gas to the plasma chamber 14 and discharging between the electrode 1 and the nozzle member 2. It is possible. The formed pilot arc is the nozzle member 2
The hole 2a of the second nozzle member 3 and the hole 3a of the second nozzle member 3 are blown out to the outside and come into contact with a workpiece (not shown). At this time, when a voltage is applied between the electrode 1 and the workpiece to cause a discharge, a plasma arc is formed between the electrode 1 and the workpiece, and at the same time, the power supply between the electrode 1 and the nozzle member 2 is stopped, thereby causing a pilot arc. Is stopped, thereby maintaining the plasma arc formed between the electrode 1 and the workpiece.

With the formation of the plasma arc, oxygen gas or another gas is supplied to the secondary airflow chamber 16 and ejected from the holes 3a of the second nozzle member 3, respectively. It is possible to inject an air current. When the plasma torch A is moved in a predetermined direction while injecting the plasma arc and the secondary airflow toward the workpiece, the plasma arc oxidizes and melts the workpiece in this moving process. At the same time, it is possible to cut the workpiece by forming a continuous groove by removing the oxide and the melt from the workpiece.

In particular, it is possible to narrow down the plasma arc that has passed through the injection hole 2a of the nozzle member 2, and it is possible to perform fine and precise processing.

[0025]

As described in detail above, in the plasma torch according to the present invention, a material having a high melting point or a high thermal conductivity is arranged around the injection hole of the nozzle member.
Damage due to heat when the plasma arc passes through the injection hole can be reduced, and the life of the plasma torch can be extended.

The diameter of the plasma arc can be reduced by reducing the diameter of the injection hole, or the plasma arc can be narrowed down by efficiently cooling the passing plasma arc and enhancing the thermal pinch effect.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a plasma torch.

FIG. 2 is a sectional view showing a nozzle member according to the first embodiment.

FIG. 3 is a sectional view showing a nozzle member according to a second embodiment.

[Explanation of symbols]

 Reference Signs List A Plasma torch 1 Electrode 1a Electrode material 1b Back surface 2 Nozzle member 2a, 3a Injection hole 2b Body 3 Second nozzle member 4 Electrode base 5 Screw 6 Main body 7 Cooling pipe 8 Passage 9 Centering stone 9a Hole 10 Insulation member 11 Passage 12 Mounting Member 13 Nozzle stand 13a Screw 13b Depression 14 Plasma chamber 15 Cap 16 Secondary airflow chamber 17a Base material 17b Insertion material

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Seiji Mizuno 222-1, Naganuma-cho, Isesaki-shi, Gunma F-term in Gunma Koike Co., Ltd. (reference) 4E001 LD20 LE08 LE09 LH10 ME04 ME06 ME10

Claims (1)

[Claims] 1. An electrode attached to an electrode base having conductivity, a nozzle member disposed opposite to the electrode and attached to a nozzle base having conductivity, and between the electrode and the nozzle member. And a plasma torch for processing a workpiece by injecting a plasma gas supplied to the plasma chamber and converted into plasma from an injection hole of a nozzle member to the outside, the plasma torch comprising: ,
A plasma torch comprising copper or a copper alloy as a base material and a part or all of the injection holes formed of a material having a higher melting point or a higher thermal conductivity than the base material.