JPH058047A - Plasma torch nozzle - Google Patents

Abstract

(57) [Summary] [Purpose] Even if molten dross adheres to the outer surface of the nozzle,
Double arc can be prevented. [Structure] Outer surface 1 of nozzle 11 of plasma torch 10
1a is coated with a substance 40 having high electrical insulation and high thermal conductivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nozzle of a plasma torch used for plasma processing such as cutting by plasma and plasma welding, and particularly when a molten dross adheres to the outer surface of the nozzle, a double arc is generated The present invention relates to a plasma torch nozzle capable of blocking the above.

[0002]

2. Description of the Related Art Conventional nozzles for plasma torches are generally machined from a highly heat conductive material such as pure copper. It is not known that the nozzle is surface-treated after the machining.

[0003]

However, the nozzle of the conventional plasma torch described above will be described in detail with reference to FIG. 2 when the plasma processing is performed or the processing is started (especially, during piercing). Work piece 20 on outer surface 11a
If the molten dross 21 from the
A double arc is induced by the abnormal discharge path 30 (in the example of the plasma torch shown in the figure, the electrode 12, the cooling water flow passage 13, the cap 14, the nozzle 11, and other parts not shown). It is configured).

When this double arc is generated, the nozzle 11 is damaged and deformed, and the processing quality is deteriorated. In order to prevent the occurrence of such an inconvenience, it is sufficient to prevent the molten dross 21 from adhering to the outer surface 11a of the nozzle 11. However, it is practically difficult to prevent the adhesion of the molten dross 21 in this way.

It is an object of the present invention to provide a nozzle of a plasma torch which can prevent the double arc from being generated even if the molten dross adheres to the outer surface of the nozzle, paying attention to the problems of the above conventional techniques. ..

[0006]

In order to achieve the above object, the nozzle of the plasma torch according to the present invention will be described with reference to FIG. 1. The outer surface 11a of the nozzle 11 has high electrical insulation and high thermal conductivity. The coating is performed with the substance 40 having the property.

[0007]

According to this structure, even if the molten dross 21 adheres to the outer surface 11a of the nozzle, the double arc can be prevented from occurring. That is, the outer surface 11a of the nozzle 11
First, the coating material 40 is a highly electrically insulating material. For this reason, it is difficult to form an abnormal discharge path, and it is possible to prevent the occurrence of a double arc. Further, the coating material 40 is also a highly heat conductive material. Therefore, even if the molten dross heat or the plasma heat is once absorbed by the coating substance 40, it immediately conducts heat to other constituent members of the plasma torch 10, and damage such as crack destruction due to thermal stress of the coating substance 40. To prevent
The high electrical insulation of the coating material 40 is maintained. This virtuous cycle is repeated.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The most preferred embodiment of the present invention will be described below with reference to FIG. In the figure, the first embodiment shows a nozzle 1
The outer surface 11a of No. 1 is coated with a thin film of diamond 40.

The second embodiment has a structure in which a thin film of CBN is used instead of the above diamond.

The coating material of the diamond thin film or CBN thin film can be easily formed on the outer surface of the nozzle by a chemical vapor deposition method such as a plasma vapor deposition method. Of course, a substance other than diamond or CBN as in the above embodiment may be used, but the essential condition is that it is a film of a substance having high electrical insulation and high thermal conductivity.

According to the above embodiment, even if the molten dross adheres, it is possible to prevent the double arc from being generated due to the adhesion. As a result, it is possible to prevent damage and deformation due to the generation of the double arc. That is, not only the nozzle of the plasma torch but also the service life of the plasma torch itself can be extended. In other words, according to the nozzle of the plasma torch of the above-mentioned embodiment, it becomes possible to maintain the plasma processing with a constant processing quality for a long period of time.

[0012]

As described above, the nozzle of the plasma torch according to the present invention has a structure in which the outer surface of the nozzle is coated with a substance having high electrical insulation and high thermal conductivity. Even if the molten dross adheres to the outer surface of the nozzle, the double arc can be prevented from being generated for a long period of time, so that it is possible to provide a nozzle of a plasma torch having high durability. As a result, in plasma processing using the nozzle of the plasma torch according to the present invention, it becomes possible to maintain a constant processing quality for a long period of time.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part of a nozzle of a plasma torch according to first and second embodiments, showing a state in use thereof.

FIG. 2 is a cross-sectional view of a main part of a nozzle of a conventional plasma torch, showing a state in use thereof.

[Explanation of symbols]

 10 Plasma Torch 11 Nozzle 11a Outer Surface of Nozzle 20 Work 21 Molten Dross 30 Abnormal Discharge Path 40 Coating Material

Claims (1)

1. A nozzle for a plasma torch, characterized in that an outer surface 11a of a nozzle 11 of the plasma torch 10 is coated with a substance 40 having high electrical insulation and high thermal conductivity.