KR100434694B1 - Plasma torch - Google Patents

Abstract

By covering the nozzle with the cap, the sputtering caused by the machining is prevented from welding to the nozzle. When the sputter damages the cap, the cost is reduced by replacing the minimum unit.

A plasma torch for jetting a plasma arc formed by discharging between an electrode (3) and a material to be processed by an orifice (7a) formed in a nozzle (7) (8) can be freely attached and detached by putting the O-ring (20) therebetween.

Description

Plasma torch

The present invention realizes reduction of running cost by covering the nozzle with the cap body and the cover member to prevent the sputter from adhering to the nozzle and replacing the cover member which is the minimum unit when the spatter is attached to the cap body and the cover member To a plasma torch.

In the plasma torch for cutting or welding the material to be processed, a negative potential is applied to the electrode, a plasma potential is applied to the nozzle, and a discharge is caused to occur between the two to form a pilot arc, and the arc is ejected from the orifice of the nozzle. And a plasma arc is formed which contributes to the processing by discharging the plasma arc between the electrode and the electrode.

For example, as shown in Fig. 3, a nozzle 7 having an orifice for passing a plasma arc across the electrode 3 is disposed at the tip of the plasma torch. Is attached to the torch body by the cap (12), and the cooling water is allowed to flow into the space formed by the torch body and the cap (12). In such a plasma torch, the tip end of the nozzle 7 is arranged opposite to the material to be processed and is exposed to the outside.

BACKGROUND OF THE INVENTION [0002] In recent plasma torches, particularly plasma torches for cutting a workpiece, the mainstream is configured to be able to form a flow of secondary gas around the plasma arc. The plasma torch includes a first nozzle having a first orifice for passing a plasma arc toward an electrode, and a second nozzle having a second orifice for passing a plasma arc and a secondary gas outside the first nozzle .

In the plasma torch described above, for example, in the technique disclosed in Japanese Patent Publication No. 2-504603, there is provided a nozzle having a nozzle orifice and a shield having an outlet orifice, and the shield is disposed in a state exposed to the material to be processed have.

When a work such as welding or cutting is performed using a conventional plasma torch, a sputter made of molten metal or oxidation product is generated and scattered along with machining. Since the nozzle is formed of a metal having conductivity, a part of scattered sputter is deposited on the exposed portion of the nozzle to cause damage. When the number of spots deposited on the nozzle increases with the increase of the processing time, the deposited sputter comes into contact with the material to be processed, causing the nozzle to be at the same potential as the material to be processed and generate double arc, So that machining may be interrupted. For this reason, there is a problem that the exposed portion of the nozzle must be cleaned or the nozzle must be replaced regularly.

In the technique disclosed in Japanese Patent Laying-Open No. 2-504603, the double arc is prevented by electrically insulating the nozzle from the shield. However, in this technique, it is also not possible to prevent the sputter from being welded or attached to the shield, It is necessary to replace the shield with an increase in machining time.

The nozzles are required to be machined with high precision such as the dimensions of the orifices, the forming position, the outer diameter, and the like. For this reason, there is a problem that the running cost is inevitably increased and the running cost is increased if the exchange frequency is high.

It is an object of the present invention to provide a cap member and a cover member which are capable of preventing a sputter generated during processing from being welded to a nozzle and covering the cap member and a cover member, And a plasma torch capable of reducing running costs by exchanging members.

1 is a view for explaining a configuration of a tip portion of a plasma torch of the present invention;

FIGS. 2A and 2B are cross-sectional views illustrating an embodiment in which a cover member is closely attached to a nozzle; FIG.

2C and 2D are cross-sectional views illustrating an embodiment in which the cover member is integrally bonded to the nozzle;

Fig. 3 is a view for explaining a configuration of a tip portion of a general plasma torch, and is a sectional view for explaining a configuration of a cap. Fig.

Description of the Related Art

A: Cassette

B: Cap

1: Attachment pipe

3: Electrode

5: Insulation pipe

7: Nozzle

8: Cover member

11: Centering Stone

12: Capsule

20: O ring

According to an aspect of the present invention, there is provided a plasma torch including a plasma torch formed by discharging a plasma arc between an electrode and a workpiece from an orifice toward a workpiece to be processed, And an insulated cover member is detachably arranged via an O-ring.

In the plasma torch, a cover member having a hole slightly larger than the orifice formed in opposition to the orifice formed in the nozzle is brought into close contact with the tip of the nozzle, and the tightly attached cover member is fixed to the torch body by the cap body. It is possible to cover almost all of the nozzles. Therefore, there is no fear that the sputtering caused by the machining will adhere to the nozzle, and no damage is given to the nozzle.

Further, since the spatter scattering from the machining portion is rapidly cooled by the atmosphere, even if the spatter scattered at a long distance adheres to a metal having a relatively low melting temperature, the metal is not melted but simply adhered. Such a sputter is easily separated from the attaching portion by cleaning and does not damage the attached metal portion.

Therefore, since the cap is constituted by the cover member set corresponding to the nozzle formed by using the metal material and the cap body detachably attaching the cover member, the portion to be damaged by the sputter can be stopped by the cover member. When the damage of the cover member is grown, only the cover member is exchanged, so that it is possible to make the replaceable parts as a minimum unit due to the damage. Therefore, the running cost required for machining including the cost of the replacement part can be reduced as much as possible.

It is preferable to insulate the cover member from the potential of the nozzle. For this purpose, the cover member itself is formed of a ceramic material or the cover member formed of a metal material is subjected to an insulation treatment at least on the contact surface with the nozzle or the contact surface with the cover member of the nozzle do. It is preferable that the insulating treatment is performed by overlapping ceramic and tetrafluoroethylene resin.

The cover member is formed by ceramics, or the contact surface or the entire surface with the nozzle is subjected to the insulation treatment, and also, for example, by inserting the insulating sleeve between the cap body and the torch body, It is possible to electrically insulate the cover member from the nozzle by performing an insulation process. Therefore, even when the cover member is directly or indirectly contacted with the workpiece, the nozzle does not become the same potential as the workpiece, and the occurrence of double arc can be prevented.

Further, by forming the composite coating by superposing the ceramic and the tetrafluoroethylene resin in the insulating treatment, the surface of the coating layer can be smoothened, and the cover member and the nozzle can be brought into close contact with each other in a good state. Further, even in the case where the sputter is adhered to the insulating treatment surface, the thermal shock caused by the sputter is relaxed, and the ceramic layer is not peeled off.

Hereinafter, an embodiment of the plasma torch will be described with reference to the drawings. Fig. 1 is a view for explaining a configuration of a tip portion of a plasma torch according to the present invention. 2 is a cross-sectional view illustrating the configuration of the nozzle and the cover member.

The plasma torch according to the present invention is constructed so as to cover the nozzle with the cap body and the cover member to prevent the sputter from adhering to the nozzle and to limit the portion to be damaged by the sputter to replace the cover member which is the minimum unit component, And the running cost are reduced as much as possible. In general, the nozzle portion of the plasma torch is supplied as a replaceable consumable item called a chip. The cover according to the present invention is likewise supplied with this chip alone or in combination.

A specific configuration of the tip portion of the plasma torch will be described. 1, the attachment pipe 1 is connected to a negative electrode of a power source via an unillustrated electrode stand, that is, a distributing member.

The cooling pipe 2 is disposed inside the attaching pipe 1 having conductivity, and the cooling pipe 2 is fixed to a not-shown fixing portion. When the electrode 3 is attached to the tip of the attachment pipe 1, the passage 4 of the cooling water together with the cooling pipe 2 is formed inside the pipe 1. [

An insulating pipe 5 having an insulating property is provided at a distance from the outer periphery of the attaching pipe 1 at a predetermined distance. The insulation pipe 5 is inserted into an annular groove formed by an electrode rod and a channel member not shown at one end and engaged with the step portion 6a formed at the inner periphery of the head 6, A). Further, the space formed between the insulating pipe 5 and the attaching pipe 1 has a function as the plasma gas passage 13.

The head 6 has a function of attaching the nozzle (chip) 7 and the cap B composed of the cover member 8 and the cap body 12 and attaching these members to the torch body.

A screw 1a is formed at the tip of the attachment pipe 1 constituting the cassette A. In the screw 1a, an electrode 3 in which an electrode 3a is embedded in the center is detachably mounted.

The inside of the nozzle 7 is entirely inverse abstracted to form an orifice 7a through which the plasma torch and the plasma gas flow pass. The outer surface of the nozzle 7 has a body 7b, a seal portion 7b, A cylindrical upper portion 7d, and a tapered portion 7e. An O-ring groove 9 is formed in the trunk portion 7b and a nozzle step portion 10 is formed at the base of the cylindrical portion 7d. The cylindrical upper portion 7d is fitted and fitted in the fitting hole 6b formed in the head 6. For this purpose, the cylindrical portion 7d and the fitting engagement hole 6b are formed to have a predetermined fitting engagement tolerance.

The body 7b of the nozzle 7 has an opening 8a which is slightly larger than the orifice 7a and at the same time the insulated cover member 8 is fitted and engaged from the potential of the nozzle 7.

2 (a) shows a state in which the insulated cover member 8 is inserted from the potential of the nozzle 7 through the O-ring 20 which is attached to the O-ring groove 9 formed in the trunk portion 7b of the nozzle 7, Combined.

Fig. 2 (b) shows a spiral formed on the trunk portion 7b of the nozzle 7, and the cover member 8 insulated from the nozzle potential is threadedly engaged by a spiral.

2 (c) shows a state in which the trunk portion 7b of the nozzle 7, the diper portion 7e are engaged with each other by the inner diameter of the insulated cover member 8 from the nozzle potential and the fitting engagement tolerance of the tapered portion 7e It is close.

2 (d) shows the inside of the cover member 8 insulated from the nozzle potential at the body portion 7b and the nozzle step portion 10 of the nozzle 7 by being worked and adhered within a predetermined adhesion tolerance .

1, a centering stone 11 having insulation properties is disposed on the electrode 3 attached to the attachment pipe 1, and the centering stone 11 is connected to the nozzle 3, (A) by the cover member (8) and the cap body (12) while being inserted into the inside of the cassette (7).

The centering stone 11 intervenes between the electrode 3 and the nozzle 7 to electrically isolate the centering stone 11 and the nozzle 7 and to rotate the plasma gas passing through the plasma gas passage 13 to surround the electrode 3 .

The cap body 12 does not need to have conductivity. The cup 12 is provided with a screw 12a screwed to the screw 6a formed on the head 6 at the end on the cassette A side in the inner circumferential surface, Is formed using a metal material.

The cap body 12 is entirely inversed abstraction. A hole 12b through which the cover member 8 is fitted is formed on the tip end side. A flange-like stop portion 12c is formed around the hole 12b .

The cover member 8 is formed so as to have a taper as a whole and has a body portion 8b fitted to the hole 12b of the cap body 12 and a tapered portion 8c continuous from the body portion 8b to the tip end side, And a flange portion 8d formed on the opposite side of the tapered portion 8c of the body portion 8b. A hole 8a having a size slightly larger than the orifice 7a of the nozzle 7 is formed on the end surface of the tapered portion 8c. An O-ring groove 8e is formed in the body portion 8b.

The outer diameter of the body portion 8b has a dimension slightly smaller than that of the hole 12b of the cap body 12. [ The end face of the flange portion 8d on the side of the body portion 8b is engaged with the stop portion 12c formed on the cap body 12 and the cap body 12 is engaged with the stopper portion 12c of the base 6 by the screw 12a. And screwed into the threaded portion 6c.

A function of applying pressure to the nozzle 7 by the cover member 8 in close contact with the nozzle 7 when the cover member 8 is screwed onto the cassette A in the cap body 12 Respectively.

The stopper portion 12c engages with the flange portion 8d of the cover member 8 when the cover member 8 is fitted into the hole 12b of the cap body 12. [ The flange portion 8d of the cover member 8 is engaged with the body 7 of the nozzle 7 by fitting the nozzle 7 into the cap B in which the cover member 8 is fitted to the cap body 12, 7b and the tapered portion 7e. Therefore, by screwing the cap B to the cassette A, it is possible to mount the nozzle 7 on the cassette A and to cover substantially the entire surface of the nozzle 7.

In the plasma torch constructed as described above, the electrode 3 is fixed to the attachment pipe 1 constituting the cassette A, and the nozzle 7 having the centering stone 11 sandwiched between the electrodes 3 Even when the attaching pipe 1 is staggered from the axis center of the plasma torch when the attaching pipe 1 is attached to the fitting hole 6b of the nozzle 6, The centering stone 11 is brought into contact with the electrode 3 to correct the displacement of the attachment pipe 1 and the gap between the electrode 3 and the nozzle 7 It is possible to ensure the coaxial characteristic of the formed orifice 7a.

By screwing the cap body 12 to the screw 6c formed on the head 6, the nozzle 7 is attached to the cassette A by these members and the passage 4a of the cooling water is formed , And it is also possible to cover substantially the entire surface of the nozzle 7 by the cap B. [

In the plasma torch, the cover member 8 constituting the cap B is formed to have a dimension approximately equal to or slightly larger than that of the tip end of the nozzle 7, and is configured to be detachable with respect to the cap body 12 . Therefore, the sputter scattering during machining mainly fuses to the cover member 8, and the spatter scattered to the cap body 12 is cooled by the atmosphere.

Therefore, damage by the sputtering can be stopped by the cover member 8.

When the cover member 8 mounted on the nozzle 7 is damaged, the cap B is detached from the cassette A and the damaged cover member 8 is replaced with a new cover member 8 Lt; / RTI > That is, when the plasma torch is damaged by the sputter, it becomes possible to replace the cover member 8 as a minimum unit.

In the present embodiment, at least an insulating process of a ceramic layer and a tetrafluoroethylene resin layer on the contact surface of the cover member 8 constituting the cap B with respect to the nozzle 7 or the contact surface of the nozzle with the cover member 8 As shown in Fig. 1, the insulating sleeve 14 is interposed between the cap body 12 and the head 6, or the contact surface of the cover member 8 with respect to the nozzle 7, The cap B is electrically insulated from the nozzle 7 by performing the insulating process including the ceramic layer and the ethylene tetrafluoride resin layer on the contact surface with the cap 12.

By electrically insulating the cap B and the nozzle 7 selectively employing the above method, even if the cover member 8 is in direct or indirect contact with the material to be processed, the nozzle 7 is the same as the material to be processed The potential does not become a potential, and it is possible to prevent occurrence of double arc.

Particularly, when the cap B is screwed to the cassette A and the cover member 8 is brought into pressure contact with the nozzle 7, it is preferable that the contact surfaces of both are brought into smooth contact over the entire surface. That is, when the cover member 8 and the nozzle 7 are not evenly contacted, there is a risk that a difference in surface pressure is generated, and deformation occurs in any member, and the machining performance is not maintained.

However, in the coating layer composed of the ceramic layer and the tetrafluoroethylene resin layer, even if irregularities are formed on the surface of the ceramic layer by thermal spraying, the irregularities can be filled with the tetrafluoroethylene resin layer to make a smooth surface. For this purpose, a coating layer composed of a ceramic layer and a tetrafluoroethylene resin layer is formed on the contact surface of the cover member 8 with respect to the nozzle 7, so that it can be evenly contacted.

As described above, at least the coating layer having the insulating property composed of the ceramic layer and the tetrafluoroethylene resin layer is formed on the contact surface of the cover member 8 with the nozzle 7 or the contact surface of the nozzle 7 with the cover member 8 At the same time, by forming the coating layer on the contact surface between the cover member 8 and the nozzle 7 and the contact surface with the cap body 12 by inserting the insulating sleeve 14 between the cap body 12 and the head 6, It is possible to prevent the occurrence of double arcing even when the member 8 is insulated from the nozzle 7 and the cover member 8 directly or indirectly comes into contact with the material to be processed.

As described above, in the plasma torch according to the present invention, since the nozzle is covered with the cap body and the cover member, the adhesion of the sputtering to the nozzle can be prevented. Therefore, the nozzle is not damaged by the sputtering, and the replacement frequency of the nozzle can be reduced.

In addition, by removing the cap body with screws by combining the cover member to be detachably attached to the nozzle, the portion to be damaged by the sputter is stopped on the cover member, and when the cover member is damaged, It is possible to reduce the cost of the replacement part and to reduce the processing cost as much as possible.

Further, by electrically insulating the cover member constituting the cap from the nozzle, even if the cover member directly or indirectly contacts the material to be processed, the nozzle does not become the same potential of the material to be processed. Therefore, it is possible to prevent the generation of double arcs.

Claims (6)

A plasma torch for spraying a plasma arc formed by discharging between an electrode and a workpiece to be sprayed from an orifice toward a workpiece, A cover member insulated from the nozzle at the tip of the nozzle is removably disposed through an O-ring; The cover member is formed of a metallic material; Wherein a coating layer composed of a ceramic layer and an ethylene fluoride resin is provided on a contact surface of the cover member with the nozzle or a contact surface of the nozzle with the cover member. A plasma torch for spraying a plasma arc formed by discharging between an electrode and a workpiece to be sprayed from an orifice toward a workpiece, A cover member insulated from the nozzle is detachably disposed at the tip of the nozzle by screwing; The cover member is formed of a metallic material; Wherein a coating layer composed of a ceramic layer and an ethylene fluoride resin is provided on a contact surface of the cover member with the nozzle or a contact surface of the nozzle with the cover member. A plasma torch for spraying a plasma arc formed by discharging between an electrode and a workpiece to be sprayed from an orifice toward a workpiece, An insulated cover member is fitted to the tip of the nozzle so as to be detachable from the nozzle; The cover member is formed of a metallic material; Wherein a coating layer composed of a ceramic layer and an ethylene fluoride resin is provided on a contact surface of the cover member with the nozzle or a contact surface of the nozzle with the cover member. A plasma torch for spraying a plasma arc formed by discharging between an electrode and a workpiece to be sprayed from an orifice toward a workpiece, And a cover member insulated from the nozzle is adhered to the tip of the nozzle so as to be detachable; The cover member is formed of a metallic material; Wherein a coating layer composed of a ceramic layer and an ethylene fluoride resin is provided on a contact surface of the cover member with the nozzle or a contact surface of the nozzle with the cover member. A plasma torch for spraying a plasma arc formed by discharging between an electrode and a workpiece to be sprayed from an orifice toward a workpiece, Wherein a cover member formed of ceramic is fastened to the nozzle by brazing at the tip of the nozzle so as to prevent the spatter scattering during machining from adhering to the nozzle. A plasma torch for spraying a plasma arc formed by discharging between an electrode and a workpiece to be sprayed from an orifice toward a workpiece, A chip facing the electrode and adhered with an insulating layer interposed therebetween, Wherein a cover member insulated by a coating in which a ceramic and an ethylene fluoride resin are superimposed from a nozzle is attached to the tip of the chip in a detachable manner.