JP3260018B2 - Plasma cutting torch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma cutting torch capable of improving the perpendicularity of a cut surface.

[0002]

2. Description of the Related Art When cutting nonferrous metals or nonmetals, a tungsten electrode is used to supply argon gas or hydrogen gas as plasma gas to the electrode, and the generated plasma arc is converted into an axial flow parallel to the plasma torch from a nozzle. An injecting plasma torch is provided. It is known that this plasma torch can form a good cut surface without causing any inclination in the cut surface.

When cutting a steel plate or a stainless steel plate, an oxidizing gas such as oxygen gas or air is used as a plasma gas. When copper or tungsten is used for an electrode in a plasma torch using an oxidizing gas, the electrode is immediately oxidized and consumed. For this reason, an electrode formed by embedding hafnium on the surface of a copper material formed in a cup shape is used as an electrode.

In the above-mentioned plasma torch, when an oxidizing gas serving as a plasma gas is injected as an axial flow parallel to the axis of the plasma torch, a starting point of the plasma arc on the surface of the electrode is not stabilized, and the plasma arc itself is not stabilized. Are unstable or a series arc may occur. For this reason, it is general that the plasma gas is swirled around the electrode to stabilize the starting point of the plasma arc.

[0005]

However, the above-mentioned plasma torch has a problem that the perpendicularity of the cut surface is different depending on the turning direction of the plasma gas and the cutting direction. That is, as shown in FIG. 5, for example, when the plasma gas is turning right with respect to the direction of cutting when viewed from the upper surface of the workpiece, the perpendicularity of the right cut surface in the workpiece is ensured. However, there is a problem that the cut surface on the left has a large inclination and cannot be a product.

An object of the present invention is to provide a plasma cutting torch capable of improving the perpendicularity of a cut surface on both sides of a kerf regardless of a turning direction of plasma gas and a moving direction of cutting. .

[0007]

SUMMARY OF THE INVENTION The problem described above is that, on the right side of the cutting direction, the traveling vector of the plasma torch and the swirl vector of the plasma arc cancel each other, and the plasma arc flows in a direction substantially perpendicular to the surface of the workpiece. On the left side, it is generated when the traveling vector of the plasma torch and the swirling vector of the plasma arc act synergistically to have a large swirling component on the cut surface. Conceivable.

[0008] Therefore, regardless of the turning direction of the plasma arc and the direction of cutting, the flow of gas directly acting on the cut surface is made substantially parallel, that is, along the plasma arc. By injecting a secondary airflow that cancels out the turning of the airplane, it is possible to improve the verticality of the cut surface.

Therefore, in order to solve the above-mentioned problems, a plasma cutting torch according to the present invention supplies a swirling oxidizing gas around an electrode and injects a swirling plasma arc from a nozzle toward a workpiece. In a plasma cutting torch (hereinafter simply referred to as "plasma torch"), a secondary nozzle is arranged around the nozzle, and the rotation of the plasma arc is canceled from the secondary nozzle to improve the verticality of the cut surface. It is configured to inject a measuring secondary airflow.

[0010] In the above-mentioned plasma torch, an axial flow injecting member for injecting a secondary air stream parallel to the axis of the plasma torch upstream of a nozzle hole of the secondary nozzle, or a swirling direction of a plasma arc in the secondary arc. It is preferable to dispose a swirling ejection member that swirls in the direction opposite to the above and ejects.

[0011]

According to the plasma torch, the perpendicularity of the cut surface on both sides of the cut groove can be improved. That is, by canceling the turning of the plasma arc by the secondary airflow injected from the secondary nozzle, the influence of the turning of the plasma arc on the cut surface can be eliminated, and the verticality can be improved.

By disposing an axial flow injecting member for injecting the secondary air flow as a flow (axial flow) parallel to the axis of the plasma torch upstream of the nozzle hole of the secondary nozzle, and injecting the secondary air flow, The turning of the plasma arc can be canceled by the secondary airflow.

[0013] Further, a swirling injection member for swirling the secondary airflow in a direction opposite to the swirling direction of the plasma arc is disposed upstream of the nozzle hole of the secondary nozzle to inject the secondary airflow.
The turning of the plasma arc can be canceled by the secondary airflow.

Therefore, the plasma arc can be generated without affecting the cut surface due to the turning of the plasma arc and stabilizing the starting point of the plasma arc on the surface of the electrode.

[0015]

An embodiment of the above-mentioned plasma torch will be described below with reference to the drawings. 1 is a schematic cross-sectional view of a plasma torch, FIG. 2 is a diagram illustrating a configuration of an axial flow injection member, FIG. 3 is a diagram illustrating a configuration of a swirling injection member, and FIG. 4 is a diagram illustrating a relationship between a plasma arc and a secondary airflow. FIG.

In the figure, an axis 1a of a plasma torch 1 is shown.
An electrode 2 having an electrode material 2a made of hafnium embedded therein is disposed thereon, and the electrode 2 is detachably attached to a tip of a cooling pipe 3 through which cooling water flows. A primary nozzle member 4 having a primary nozzle hole 4a is disposed facing the electrode 2, and is detachably mounted on a pipe-shaped partition member 5 disposed inside the plasma torch 1. Further, a secondary nozzle member 6 having a secondary nozzle hole 6a is disposed so as to face the primary nozzle member 4, and is detachably attached to the torch main body 7.

In the above configuration, the electrode material 2a, the primary nozzle hole 4a, and the secondary nozzle hole 6a are arranged on the axis 1a of the plasma torch 1, respectively. Further, inside the plasma torch 1, a passage 8 for flowing a plasma gas is formed between the cooling pipe 3 and the partition member 5, and a gas for forming a secondary air flow between the partition member 5 and the torch body 7 is distributed. A secondary passage 9 is formed.

The passage 8 is connected to a plasma gas supply source 11 by a hose 10. The secondary passage 9 is also connected by a hose 12 to a gas supply source 13 for forming a secondary airflow.

The passage 8 is provided with a centering stone 14 for swirling the plasma gas and injecting it on the surface of the electrode 2 (the surface of the electrode material 2a). The centering stone 14 has a plurality of holes 14a inclined in the circumferential direction about the axis 1a. The plasma gas passes through the holes 14a and turns according to the inclination of the holes 14a. Is configured to obtain.

By injecting the plasma gas onto the surface of the electrode 2 in a swirled state as described above, the starting point of the plasma arc in the electrode material 2a can be made to coincide with the axis 1a in a stable state. In addition, the possibility that a series arc is generated can be reduced, and a stable plasma arc can be formed and processed.

The secondary passage 9 has an axial flow injection member shown in FIG.
15 or the swirling injection member 16 shown in FIG. 3 is selectively disposed. Each of the members 15, 16 is for injecting a secondary airflow as an axial flow or a swirling flow along the outer periphery of the plasma arc which is injected while being swirled from the primary nozzle hole 4a. Has a function of canceling the turning of the plasma arc.

That is, as shown in FIG. 4A, when a secondary airflow as an axial flow 18 is injected along the circumference of the swirled plasma arc 17, the swirling component of the plasma arc 17 is the axial flow 18 And is attenuated as the distance from the secondary nozzle hole 6a increases. The plasma arc 17 is wrapped by the axial flow 18. For this reason, the plasma arc 17 and the axial flow 18 acting on the workpiece 19 are flows in a direction substantially parallel to the cut surface. Therefore, it is possible to improve the perpendicularity of the cut surface.

As shown in FIG. 2B, a secondary airflow as a swirling flow 20 which is swirled in the direction opposite to the swirling direction of the arc 17 was injected along the circumference of the swirled plasma arc 17. In the case, the swirling component of the plasma arc 17 is the swirling flow 20
And the flow becomes axial as the distance from the secondary nozzle hole 6a increases. Therefore, when the workpiece 19 is cut, it is possible to improve the perpendicularity of the cut surface.

The axial flow injection member 15 is formed by forming a plurality of holes 15a in parallel with the axis 1a of the plasma torch 1 in a member obtained by molding an insulating material such as ceramics into a cylindrical shape. For this reason, the gas supplied to the secondary passage 9 flows in parallel with the axis 1a when passing through the hole 15a of the axial flow injection member 15, and as an axial flow 18 shown in FIG. It is ejected from the next nozzle hole 6a to the outside.

Therefore, when the axial flow 18 is jetted as a secondary airflow from the secondary nozzle hole 6a while the plasma arc 17 is jetted from the primary nozzle hole 4a, the axial flow 18 flows along the outer periphery of the plasma arc 17. It flows so as to cover the arc 17. At this time, the plasma arc 17 is attracted by the axial flow 18 in parallel with the axis 1a, and the swirling component of the arc 17 is canceled.

The swirling injection member 16 is formed by forming a plurality of holes 16a inclined in the circumferential direction about the axis 1a of the plasma torch 1 in a cylindrical member having an insulating property. The inclination direction of the hole 16a is set opposite to the inclination direction of the hole 14a of the centering stone 14 provided in the passage 8.

For this reason, when the gas supplied to the secondary passage 9 passes through the hole 16a of the swirling injection member 16, the gas swirls around the axis 1a and forms a swirling flow 20 shown in FIG. It is ejected from the secondary nozzle hole 6a of the member 6 to the outside.
Therefore, the swirling component of the plasma arc 17 injected in a swirling state from the primary nozzle hole 4 a is canceled by the swirling component of the swirling flow 20.

In FIG. 1, reference numeral 21 denotes a power source connected to the electrode 2, the primary nozzle member 4, and the workpiece 19.

[0029]

As described above in detail, in the plasma torch according to the present invention, the swirling component of the plasma arc injected in the swirling state is canceled by the secondary airflow, so that the plasma arc is applied to the surface of the workpiece. The axial flow can be made in a substantially vertical direction and parallel to the axis of the plasma torch. Therefore, the verticality of the cut surface can be improved without being affected by the cutting direction and the plasma arc turning direction.

Further, since the axial flow jetting member or the swirling flow jetting member is arranged on the upstream side of the secondary nozzle hole formed in the secondary nozzle member, the swirling component of the plasma arc is generated by the secondary airflow passing through these jetting members. Can be canceled.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a plasma torch.

FIG. 2 is a diagram illustrating a configuration of an axial flow injection member.

FIG. 3 is a diagram illustrating a configuration of a swirling injection member.

FIG. 4 is a diagram illustrating a relationship between a plasma arc and a secondary airflow.

FIG. 5 is a diagram illustrating a problem.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plasma torch 1a Shaft center 2 Electrode 2a Electrode material 4 Primary nozzle member 4a Primary nozzle hole 6 Secondary nozzle member 6a Secondary nozzle hole 7 Torch main body 8 Passage 9 Secondary passage 11 Plasma gas supply source 13 Form secondary air flow Supply source 14 of centering stone 14a, 15a, 16a hole 15 axial flow injection member 16 swirl injection member 17 plasma arc 18 axial flow 19 work material 20 swirl flow 21 power supply

Continuation of the front page (56) References JP-A-7-144278 (JP, A) JP-A-5-84579 (JP, A) JP-A-57-165370 (JP, U) Table 6-508793 (JP) , A) (58) Fields studied (Int. Cl. ⁷ , DB name) B23K 10/00 H05H 1/34

Claims (3)

(57) [Claims] In a plasma cutting torch for supplying a swirling oxidizing gas around an electrode and injecting a swirling plasma arc from a nozzle toward a material to be cut, a secondary nozzle is provided around the nozzle. A plasma cutting torch, wherein the secondary nozzle is arranged and a secondary airflow is injected from the secondary nozzle to cancel the turning of the plasma arc to improve the perpendicularity of the cut surface. 2. The plasma cutting apparatus according to claim 1, further comprising an axial-flow injection member for injecting a secondary air stream in parallel with an axis of a plasma cutting torch on an upstream side of a nozzle hole of the secondary nozzle. torch. 3. The swirling member for swirling and injecting a secondary airflow in a direction opposite to a swirling direction of a plasma arc is disposed upstream of a nozzle hole of the secondary nozzle. Plasma cutting torch.