JPH05237664A - Plasma torch - Google Patents

Abstract

PURPOSE:To perform cutting and chipping work of based material to be machined in the plasma torch using orifice gas. CONSTITUTION:In a tip 6 arranged on the tip of an orifice 7, the inside 11a is narrowed down in an inverse conical shape or an inverse hanging-belllike shape and communicated with a small-diameter hole 11 and the inside 12a is extended in a conical shape from the small. diameter hole 11, communicated with a cylindrical, discharge port 12 and opened outside. The orifice gas and a plasma arc are then once narrowed down mechanically and made into a plasma flow having high momentum and high density, then, the momentum of the orifice gas is dispersed to a conical inner wall, the energy density of the plasma arc is reduced and made into moderate energy density required for chipping and further, the flow of the orifice gas can be converged in the direction of the central axis on the cylindrical inside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma torch capable of cutting and chipping with a working gas.

[0002]

2. Description of the Related Art A conventional plasma torch will be described below.

As shown in FIG. 2, from a plasma power source 16 for supplying power to the plasma torch 13, a drain hose 20 which has a built-in electric wire and drains cooling water, and a water supply hose for sending cooling water to the plasma torch 13. 21, a gas hose 24 for sending a working gas, a pilot cable 23 for placing a high frequency for improving an arc start, and a switch cable 22 are bundled and extended, and a plasma torch 13 is attached to a tip end thereof. The ground cable 17 connects the plasma power source 16 and the processing base material 18.

In the figure, 14 is a compressor for compressing the working gas and sending it to the plasma torch 13, 15 is a regulator for adjusting the secondary pressure of the working gas to a constant value, and 19 is a water supply pump.

As shown in FIG. 3, at the tip of the plasma torch 13, a hollow electrode 2 is screwed and attached to the tip of a cylindrical main body metal fitting 1 to prevent leakage from the screwed portion.
The ring 3 is interposed. The introduction pipe 4 inserted in the shaft cores of the main body fitting 1 and the electrode 2 guides the cooling water to the electrode 2. A cathode material 5 made of zirconium or hafnium is embedded in the tip of the electrode 2. A tip 25 is attached to the tip of an insulator-made orifice 7 which is fitted over the rear parts of the main body metal 1 and the electrode 2 and surrounds the tip of the electrode 2 with a gap. 25 is electrically isolated. The tip 25 is made of copper or copper alloy and limits the plasma arc supplied to the base material 18.

A small-diameter hole 8 is formed at the tip of the orifice 7 and opens toward the space between the orifice 7 and the electrode 2.
Are formed.

The inner surface 11a of the tip 25 is narrowed in the shape of an inverted cone, and communicates with a small-diameter hole 11 which serves as a discharge port and is opened to the outside.

The outside of the orifice 7 is the working gas supply path 1
It is enclosed by a nozzle 9 made of an insulating material that forms 0 and prevents the conductive portion from being exposed to the outside. The tip of the nozzle 9 is joined to the tip 25. A dotted white arrow A in the drawing indicates the flow direction of the working gas supplied to the supply passage 10, and a white arrow B indicates the cooling water supplied to the electrode 2 through the introduction pipe 4 and discharged through the outside of the introduction pipe 4. Indicates the direction of flow.

The inner surface 11a of the tip 25 is narrowed in an inverted conical shape and communicates with a small-diameter hole 11 serving as a discharge port and is opened to the outside.

In the plasma torch constructed as described above, the working gas and the plasma arc are mechanically squeezed by the inner surface 11 of the tip 25 having the inverted conical shape and the holes 11 having a smaller diameter to mechanically squeeze the high momentum and the high momentum. The base material is cut into a plasma flow having an energy density.

[0011]

However, in the above-mentioned conventional structure, the working gas and the plasma arc can be cut into the base metal 18 by the tip 6 as a plasma flow of high momentum and high energy density. It had a problem that it could not be lifted.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a plasma torch capable of cutting and chipping a base material.

[0013]

In order to achieve this object, a plasma torch according to the present invention has a tip disposed at the tip of an orifice, the inner surface of which is narrowed to an inverted cone shape or an inverted bell shape, and has a small diameter. In this configuration, the inner surface is expanded from a small-diameter hole into a conical shape and communicates with a cylindrical discharge port, and is opened to the outside.

[0014]

With this configuration, the working gas and plasma arc are mechanically squeezed to a high momentum and high-density plasma flow, and then the momentum of the working gas is dispersed on the inner wall of the conical shape and the energy density of the plasma arc is increased. Lower it to the proper energy density required for fishing,
Furthermore, the flow of the working gas is focused in the central axis direction by the cylindrical inner wall.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1 showing an embodiment of the present invention, the same parts as those in the conventional example are designated by the same reference numerals and the description thereof will be omitted. In addition,
The overall configuration of the plasma torch is the same as that of the conventional example described with reference to FIG.

As shown in FIG. 1, the feature of the present embodiment is that the inner surface 11a is made of copper or a copper alloy in place of the conventional tip 25 in the above-described conventional structure and is squeezed into an inverted conical shape. And communicates with the small-diameter hole 11 whose inner diameter is φA,
The point is that the inner surface 12a is expanded in a conical shape from the small-diameter hole 11 so as to communicate with the cylindrical discharge port 12 having an inner diameter of φB and open to the outside.

That is, the relation between the inner diameter dimension A of the small-diameter hole 11 and the inner diameter dimension B of the discharge port 12 is A = 0.020 in relation to the plasma current value C (normally 50 to 150 amperes).
An appropriate plasma density can be obtained by setting | C | to 0.026 | C |. However, | C | is the absolute value of the plasma current value C. Inner diameter A is 0.020 |
When it is smaller than C |
When it is larger than | C |, the base material 18 cannot be fused. In addition, the length L ₁ of the small-diameter hole 11 is 0.5 to 2.0 mm.
To create the required working gas momentum. Length L
_{If 1} is less than 0.5, the working gas is dispersed and becomes 2.0
When larger, focus. Further, the working gas and the plasma arc are dispersed appropriately by making the inner surface 12a communicate with a conical shape having a divergence angle (twice the cone generatrice angle) θ ₁ of 30 ° to 45 ° to increase the inner diameter. Spread angle θ
_{When 1} is less than 30 degrees, the state shifts to the cutting state, and when it is more than 45 degrees, the base material cannot be melted. Further, it is connected to a cylindrical discharge port 12 having an inner diameter dimension B, and the inner diameter dimension B is made to be two to three times as large as the inner diameter dimension A, and the length L ₂ of the discharge port 12 is set to 3 to 10 mm. The opening of the opening allows the flow of the working gas to be focused in the central axis direction. When the length L ₂ of the discharge port 12 is less than 3 mm, the working gas is dispersed and the margin between the base material 18 and the tip when the base material 18 is lifted is lost, resulting in variation in the lift width, and when the length L ₂ is greater than 10 mm. Does not generate a pilot arc.

As described above, according to this embodiment, the inner surface 11
a is narrowed in an inverted conical shape and communicates with the small-diameter hole 11, and the inner surface 12a is expanded in a conical shape from the small-diameter hole 11 and communicates with the cylindrical discharge port 12 to open the tip 6 open to the outside. By providing the working gas and the plasma arc once to mechanically squeeze them into a high momentum and high-density plasma flow, the momentum of the working gas is dispersed on the inner wall and the energy density of the plasma arc is lowered to reduce the base material 18 The base material 18 can be easily lifted by adjusting the energy density to an appropriate level required for the lifting, and focusing the flow of the working gas in the central axis direction.

Thus, cutting and chipping can be performed only by exchanging the chips.

[0021]

As is apparent from the above description of the embodiments of the present invention, in the present invention, the tip provided at the tip of the orifice communicates with a small-diameter hole by narrowing the inner surface into an inverted cone shape or an inverted bell shape. Moreover, an excellent plasma torch capable of cutting and chipping the base material can be realized by the structure in which the inner surface is expanded in a conical shape from the small diameter hole and communicates with the cylindrical discharge port and is opened to the outside.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing the concept of a plasma torch according to one embodiment of the present invention

FIG. 2 is a schematic perspective view showing a cut state of a base material of a conventional plasma torch.

FIG. 3 is a sectional view of an essential part showing the concept of a conventional plasma torch.

[Explanation of symbols]

 1 Electrode 5 Cathode Material 6 Chip 11 Small Diameter Hole 12 Discharge Port

Claims (2)

[Claims] 1. An electrode made of copper or copper alloy disposed at the tip of a tubular body fitting, a cathode material attached to the center of the tip of the electrode to form an electron emission surface, and a tip of the electrode. A tip is attached to the tip of an insulator-made orifice arranged so as to surround the tip, and a working gas is introduced from the space provided on the outer periphery of the electrode into the space between the tip and the electrode through the orifice. A plasma torch that is released from the tip of the tip after opening, wherein the tip has an inner surface that is squeezed into an inverted conical shape or an inverted bell shape and communicates with a small-diameter hole, and from the small-diameter hole to the inner surface. A plasma torch having a configuration in which a cone is expanded to communicate with a cylindrical discharge port and is opened to the outside. 2. The tip has a small-diameter hole narrowed in an inverted conical shape whose inner diameter is 0.020 to 0.026 times the absolute value of the plasma current value and the length of the hole is 0.5 to 2.0 mm. And the inner diameter is increased by communicating with a conical shape having a divergence angle of 30 degrees to 45 degrees, and the inner diameter dimension is equal to the inner diameter dimension of the small-diameter hole.
The plasma torch according to claim 1, wherein the plasma torch has a structure in which it is opened in communication with a discharge port having a length of 3 to 3 times and a length of 3 to 10 mm.