JPH10277747A - Processing method and processing apparatus for workpiece - Google Patents

Abstract

(57) Abstract: A processing method and processing of a workpiece which prevents scattering of the molten metal to prevent damage and breakage of the workpiece and other structures and facilitates recovery of the molten metal. Processing device. In this processing apparatus, a workpiece 22 is installed in an atmosphere gas other than oxygen or in a vacuum, and a plasma torch 10 is provided so as to face the workpiece 22.
The plasma torch 10 ejects a working gas from a torch nozzle 13 and ejects an assist gas from a nozzle cap 18. As the working gas and the assist gas, gases other than oxygen, for example, N ₂ gas, a mixed gas of Ar and H ₂ , and an inert gas are used. The workpiece 22 is subjected to plasma arc cutting with a high-temperature and high-velocity plasma flow from the plasma torch 10 in an atmosphere gas or vacuum, and the generated molten metal 23 is caused to flow down to cut the workpiece 22. It is attached to the back side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for processing a workpiece, which performs processing such as cutting of the workpiece using a plasma flow or a laser beam having a high energy density. The present invention relates to a processing method and a processing apparatus for a workpiece in which a molten metal is captured and collected on the back side of the workpiece.

[0002]

2. Description of the Related Art In the engineering design of the International Thermonuclear Experimental Reactor (ITER), it is necessary to establish a remote maintenance technology for a thick plate structure such as a vacuum vessel, a rear wall, a blanket module and the like which constitute a central portion of the fusion reactor. Have been. For example, the blanket module 1 has a thickness of 70 mm as shown in FIG.
SUS316L is connected to the rear wall 3 via the support leg 2 made of a thick plate material. When the blanket module 1 is replaced, the support leg 2 needs to be cut. Reference numeral 4 denotes a cooling manifold.

As shown in FIG. 7, when a part of a structure 5 such as a blanket module 1 is disassembled and replaced, an arc is generated by a small-diameter nozzle 6a of a plasma torch 6 shown in FIG. Plasma arc cutting using a high-temperature and high-velocity plasma flow (plasma arc 7) obtained by constraining, or laser cutting using high-energy-density laser light is performed. The plasma arc cutting or the laser cutting is performed along the cutting line L shown in FIG. 7, and the replacement part 5a is removed. In the plasma arc cutting or laser cutting, as shown in FIG. 8, a large amount of molten metal 8 is generated by the high energy density plasma arc 7 or laser light.
Are scattered from the cut back side of the workpiece 5 which is a structure.

[0004] There is a problem that the workpiece 5 and other structures 9 are damaged or broken by the scattered molten metal 8, and when the scattered molten metal 8 adheres to the workpiece 5 and remains. However, there is a problem in that the processed surface of the workpiece 5 becomes dirty or the performance of the workpiece 5 is deteriorated.

In order to prevent the workpiece 5 from being damaged or the like, a molten metal recovery structure for capturing and recovering the molten metal 8 may be provided on the back surface of the workpiece 5 in some cases. In order to prevent melting by the molten metal, it is provided at a distance from the workpiece 5, and the recovery volume must be increased. For this reason, there is a problem in that it cannot be provided on a structure (workpiece 5) which is subject to space restrictions.

Further, in the state where the molten metal 8 adheres to the cut portion of the workpiece 5 which is a structure and remains,
In the case where another structure is welded to the cut portion of the workpiece 5 by welding, the adhered molten metal is removed by machining or the like. There were drawbacks to do.

The present invention has been made in view of the above circumstances, and prevents the molten metal from being scattered to prevent the work or other structures from being damaged or damaged by the molten metal, and to recover the molten metal. It is an object of the present invention to provide a processing method and a processing apparatus for a workpiece which can easily perform the processing.

Another object of the present invention is to provide a method of processing a workpiece in which the behavior of the molten metal during the processing of the workpiece is utilized to increase the viscosity of the molten metal to facilitate recovery of the molten metal. And a processing device.

Still another object of the present invention is to positively adhere molten metal to one side of a scrap side of a workpiece,
An object of the present invention is to provide a processing method and a processing apparatus for a workpiece which facilitates recovery of a molten metal.

Another object of the present invention is to provide a processing method and a processing apparatus for a workpiece in which a shield box is moved by following a plasma torch so that shielding by a shielding gas can be performed locally. is there.

[0011]

In order to solve the above-mentioned problems, a method for processing a workpiece according to the present invention, as described in claim 1, comprises the steps of: When the workpiece is cut in a plasma arc from a plasma torch by plasma arc cutting, the workpiece is processed in the atmosphere gas or vacuum using a gas other than oxygen as a working gas and an assist gas for the plasma torch. This is a method in which an object is cut and a molten metal is adhered to the cut back surface side of the work to be recovered.

According to a second aspect of the present invention, there is provided a method for processing a workpiece, wherein a plasma torch is inclined with respect to a vertical plane including a cutting direction. And a method of attaching and recovering a molten metal to a scrap-side cut back surface of the workpiece when performing plasma arc cutting of the workpiece with a plasma torch; This is a method in which a thin plate is provided on the cut back side of an object, and when a workpiece is cut by a plasma torch with a plasma arc, a molten metal is adhered to the thin plate and collected.

According to another aspect of the present invention, there is provided an apparatus for processing a workpiece, wherein the workpiece is installed in an atmosphere gas other than oxygen or in a vacuum. On the other hand, a plasma torch for cutting the workpiece with a plasma arc is provided facing the plasma torch, and a gas other than oxygen is used as the working gas ejected from the torch nozzle and the assist gas ejected from the nozzle cap. Things.

Further, in order to solve the above-mentioned problems, in the apparatus for processing a workpiece according to the present invention, the workpiece is provided with a thin plate on a side opposite to the plasma torch. It is a thing.

On the other hand, in order to solve the above-mentioned problems, a method of processing a workpiece according to the present invention includes a pair of shield boxes that operate following a plasma torch. When the above-mentioned shield box is placed opposite to the workpiece and the workpiece is cut with a plasma flow from a plasma torch by plasma arc cutting, the cut portion of the workpiece is locally covered with a shield gas, while the plasma torch is used. And cutting using a gas other than oxygen as the working gas and the assist gas, and collecting and collecting the molten metal on the cut back surface of the workpiece.

According to another aspect of the present invention, there is provided an apparatus for processing a workpiece according to the present invention, comprising a pair of shield boxes sandwiching the workpiece. One of the shield boxes is fixed to a plasma torch, and both shield boxes are connected by a connecting arm and installed so as to be able to move following the plasma torch. A gas other than oxygen is used for the working gas and the assist gas of the plasma torch while being covered.

Still further, in order to solve the above-mentioned problem, a method of processing a workpiece according to the present invention is described in claim 8.
As described in the above, when the workpiece is placed in an atmosphere gas or vacuum other than oxygen, and the workpiece is irradiated with a laser beam from a laser device to perform laser processing, the workpiece is treated with the atmosphere gas or vacuum. This is a method of performing drilling or cutting by using a laser beam inside, and collecting and collecting the molten metal generated by the laser beam irradiation on the irradiation back side of the workpiece.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a method and apparatus for processing a workpiece according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows a plasma cutting apparatus as an apparatus for processing a workpiece according to the present invention. This plasma cutting device includes a plasma torch 10 as a plasma generator. The plasma torch 10 has an electrode 12 supported on the distal end side of a torch main body (not shown) via an insulator 11, and this electrode 12 is connected to a plasma power supply (not shown) which is a DC power supply.

A torch nozzle 13 is arranged concentrically with the electrode 12 on the electrode tip side of the plasma torch 10. A working gas passage 14 is formed inside the torch nozzle 13. A swirler 15 that gives a swirling flow to the working gas is installed in the working gas passage 14, and the torch nozzle 13 is configured as a swirling flow nozzle. The swirler 15 is provided integrally or integrally on the outer peripheral side of the insulator 11 and is supported between the torch nozzle 13 and the insulator 11.

The working gas is provided with a swirling flow by the swirler 15 and is ejected from a small-diameter nozzle opening (orifice) of the torch nozzle 13. As the working gas, for example, a mixed gas of Ar and H ₂ is used. A mixed gas with an inert gas such as He may be used instead of Ar, and a gas other than oxygen, for example, an inert gas or N ₂ gas may be used alone as the working gas. H ₂ used in the mixed gas has an effect of improving sharpness by the plasma arc 18.

A cylindrical nozzle cap 18 is provided on the outer peripheral side of the torch nozzle 13, and a gas passage 19 for an assist gas constituting a secondary gas is formed inside the nozzle cap 18. This assist gas passage 1
9 is also provided with a swirler 20 for giving a swirling flow to the assist gas. For example, N ₂ gas is used as the assist gas. As the assist gas, an inert gas may be used, or a gas other than oxygen, for example, a mixed gas of N ₂ and H ₂ may be used. H _{2 in the} mixed gas has the effect of improving the sharpness of cutting and assisting.

The plasma torch 10 is installed obliquely with respect to a workpiece 22 of a structure to be processed. The plasma torch 10 is provided to be inclined to one side with respect to a substantially vertical plane including the work cutting direction. The plasma torch 10 tilts the torch angle (bevel angle) to the side of the workpiece that does not become a scrap, and places the workpiece 22 in an atmosphere of N ₂ gas or an inert gas or in a vacuum.

Next, the plasma torch 10 shown in FIG.
The cutting process of the SUS316L workpiece (thick plate material) 22 having a thickness of 70 mm, for example, will be described with reference to FIG.

The conditions for cutting the workpiece 22 are shown in [Example 1].

[0026]

[Outside 1]

When the workpiece (work) 22 is plasma-arc cut under the work cutting conditions of [Example 1], it is represented by a circle in FIG. 2, and the molten metal 23 adheres to one side of the cut back surface of the work. Was confirmed. When the cutting current or the cutting speed is changed, molten metal 23 adheres to both sides of the cut surface of the work as shown by a mark in FIG. 2, and further, under the cutting conditions shown by the mark, the cut surface of the work 22 is not good. I understood.

That is, in FIG. 1, when a current is supplied from the plasma power source to the electrode 12, the plasma flow from the plasma torch 10 at a high temperature and a high flow rate causes a gap between the electrode 12 and the work 22 which is a workpiece. An arc is formed. At this time, the plasma torch 10 is
The working gas is ejected from the nozzle cap 3 while the assist gas is restrained from the nozzle cap 18 and swirled. Plasma arc 1 formed by plasma flow from plasma torch 10
7 starts the cutting of the work 22. The plasma arc 17 includes a positive polarity and a negative polarity plasma arc.

At the time of cutting the work, the plasma torch 10
When the torch angle (bevel angle) is set within the range of 10 ° to 30 ° by inclining with respect to the vertical plane of the work 22 and the work cutting conditions of [Example 1] are applied, the working gas, the assist gas, and the atmosphere gas Oxidation of the molten metal 23 is thereby suppressed, and the viscosity of the molten metal 23 is increased.
Is prevented from scattering.

Also, the inclination of the plasma torch 10
The generation of the anode point (or the cathode point) 24 is biased in the workpiece (base material) 22 as the workpiece, and the anode point 24 is biased toward one cut surface. Due to the bias of the anode point 24 and the effect of the swirling flow of the working gas or assist gas, the flow MF of the highly viscous molten metal 23 is not scattered, and is directed to the back side along the scrap-side cut surface of the work 22. Flows.
Since the molten metal 23 that has flowed down to the cut back surface of the workpiece adheres to the scrap-side cut back surface of the work rear surface, which is the workpiece, the recovery and removal of the molten metal 23 becomes easy.

Even if the molten metal 23 flows to and adheres to one side of the cut back surface of the work 22, the adhered molten metal 23 has no or little effect of oxygen, and therefore has a high viscosity and remains without flowing down. That is, the molten metal 2
3 adheres to the scrap side of the work 22 and does not adhere to the remaining work 22 side. Therefore, the work 22
No need to remove the molten metal 23 from the cut surface. When another structural material is welded to the cut surface 25 of the remaining work 22 as an exchange member, the work cut surface 25
Can be directly welded as a groove surface.

Further, when this plasma arc cutting method is used for dismantling and replacing a structure, scrapping can be performed by appropriately selecting the swirling flow direction in which the plasma arc 17 from the torch nozzle 13 is restrained and the torch angle of the plasma torch 10. The molten metal 23 can be attached to one side of the structure on the side, and the molten metal 23 can be easily collected. Also,
Since the molten metal 23 is not scattered, the structure (workpiece) can be plasma-arc cut without damaging the disassembled portion or the structure other than the replacement member.

Another example of cutting a SUS316L plate having a thickness of 25 mm as the workpiece 22 is shown in [Example 2].

[0034]

[Outside 2]

Under the cutting conditions of the work 22 shown in [Example 2]
When a workpiece 22 made of a 5 mm thick plate material is plasma arc cut,
It was found that the molten metal 23 was prevented from being oxidized and increased in viscosity, and the molten metal 23 adhered to one side (scrap side) of the back surface of the work.

In the case of the work 22 having a thickness of 25 mm, it has been found that the cutting current can be reduced and the cutting speed can be increased due to the smaller thickness compared to the work having a thickness of 70 mm shown in [Example 1].

FIG. 3 shows a second embodiment of the plasma processing apparatus according to the present invention.

In the plasma heating apparatus shown in this embodiment, a workpiece 22 which is a workpiece is
This is a plasma cutting apparatus that performs a cutting process with a plasma arc 17 from 0. The basic configuration of this plasma cutting device is
Since it is not different from the plasma cutting apparatus shown in FIG. 1, the same portions are denoted by the same reference numerals and description thereof will be omitted.

The plasma cutting apparatus shown in FIG. 3 is provided with a metal thin plate 28 on the cut back side of a workpiece 22 which is a workpiece. By providing a metal thin plate 28 on the back side of the workpiece cut opposite to the plasma torch 10, the plasma torch 10
It is not necessary to install the plasma torch 10
May be set upright on the surface of the work 22, and there is no restriction on the torch angle.

This plasma cutting apparatus uses a mixed gas of Ar and H ₂ , an inert gas or N ₂ gas as a working gas for cutting a plasma arc of the work 22, and uses an N ₂ gas and an Ar and H ₂ gas as assist gases. Use a mixed gas or an inert gas. Then, an atmosphere gas around the work 22 is an inert gas such as Ar or an N ₂ gas.

When the workpiece 22 to be processed is cut by the plasma arc with the plasma cutting apparatus under the cutting conditions of the work 22, the oxidation of the molten metal 23 melted by the plasma arc 17 is suppressed, and the viscosity increases. And
When the workpiece 22 is cut by the plasma arc, the generated molten metal 23 gradually flows down and adheres to the metal thin plate 28 provided on the cut back side of the workpiece 22. The molten metal 23 adheres to both sides of the cut surface of the thin plate 28 as shown in FIG.

After the plasma arc cutting of the work 22 by the plasma cutting device, the metal thin plate 28
By removing and collecting the molten metal 23, the molten metal 23 can be easily recovered, and the adhesion of the molten metal 23 to the workpiece 22 as a workpiece can be easily and reliably prevented.

FIG. 4 shows a third embodiment of the plasma processing apparatus according to the present invention.

The plasma heating apparatus shown in this embodiment is a plasma cutting apparatus in which a cut portion of a workpiece 22 to be processed is locally covered with a shield box 30 to perform plasma arc cutting. The configuration of the plasma torch 10 used in this plasma cutting apparatus is shown in FIG.
, And the description is omitted.

The plasma torch 10 is provided with a shield box 30 opposed to the work 22 which is a workpiece, so that the shield box 30 locally covers the cut portion of the work 22 from the work cutting surface and the back side. Has become. One of the shield boxes 30 is fixed to the plasma torch 10, while the other shield box 30 is integrally connected via a connection arm 31, and the shield boxes 30, 30 follow and move integrally with the plasma torch 10. It is supposed to.

This plasma cutting apparatus is provided with a pair of shield boxes 30 that move following the plasma torch 10, and the cut section of the work 22 is locally shielded by the shield box 30 with a shield gas other than oxygen. Therefore, there is no need to cover the entire work with the shielding gas. The shielding gas includes N ₂ gas, inert gas, or a mixed gas of Ar and H ₂ . The shield gas may be blown into the shield box 30. In addition, a working gas and an assist gas ejected from the plasma torch 10 can be used as the shielding gas. In this plasma cutting device, it is possible to save the shield gas.

Also in this case, since the plasma arc cutting of the workpiece 22 can be performed with or without oxygen, the viscosity of the molten metal 23 is large, and the molten metal 23 can be effectively prevented from being scattered. . Therefore,
Breakage or damage of other structures due to scattering of the molten metal 23 can be reliably prevented.

FIG. 5 is a principle view showing a fourth embodiment of the apparatus for processing a workpiece according to the present invention.

The apparatus for processing a workpiece shown in this embodiment is a laser processing apparatus for cutting or drilling a workpiece as a workpiece using a laser beam.

This laser processing apparatus includes a laser device (not shown) that outputs a processing laser beam having a high energy density. The laser beam output from this laser device is focused by a condenser lens 34 of a laser scanning optical system 33. Irradiation is performed on the workpiece 22 which is a workpiece, and laser processing such as cutting and punching of the workpiece 22 is performed.

The laser processing of the work 22 by the laser processing apparatus is performed by setting the work 22 in an atmosphere gas other than oxygen gas or in a vacuum. The work 22 is laser-processed in an atmosphere gas other than oxygen gas or in a vacuum, and the work 22 is cut or pierced, thereby preventing oxidation of the molten metal 23 melted by laser light irradiation and reducing the viscosity of the molten metal 23. Can be enhanced. The atmosphere gas includes an inert gas such as N ₂ gas or Ar gas.

Therefore, in the laser processing of the work 22 by this laser processing apparatus, the scattering of the molten metal 23 can be prevented, and the damage or damage of other structures (not shown) due to the scattering of the molten metal 23 can be effectively prevented. Can be prevented.

In this laser processing apparatus, the laser scanning optical system 33 makes it easy to control the adjustment of the scanning direction of the laser light. By injecting the workpiece into the workpiece 22 at an appropriate inclination, the molten metal flows down the cut surface and can adhere to one side of the cut back surface of the workpiece 22.

In the embodiment of the present invention, an example is shown in which a workpiece is cut by a plasma arc from a plasma torch, but not only cutting in a narrow sense but also opening a window or drilling a hole. included.

[0055]

As described above, claims 1 and 4
In the processing method and processing apparatus for the workpiece described in the above, in the plasma arc cutting using a plasma torch, using a gas other than oxygen as a working gas and an assist gas, in an atmosphere gas other than oxygen or in vacuum Since the workpiece is cut by the plasma arc, the oxidation of the molten metal generated by the plasma arc is suppressed and the viscosity increases, and the molten metal adheres to the cut back surface of the workpiece to easily recover the molten metal It is possible to effectively prevent damage and breakage of the structure due to scattering of the molten metal.

Further, in the method for processing a workpiece according to the second aspect, the torch angle is inclined in a vertical plane including the cutting direction by using a plasma torch, so that the flow of the working gas and the assist gas is reduced. Due to the inclination of the torch angle, a bias occurs at the anode or cathode point on the workpiece side, and due to this bias, the molten metal can be easily collected and adhered to one side of the cut back surface which is the scrap side of the workpiece. At the same time, it is possible to effectively prevent damage and breakage of the structure due to the molten metal.

Further, in the method and apparatus for processing a workpiece according to the third and fifth aspects, a thin plate is provided separately from the workpiece on the cut back surface side of the workpiece, and the thin plate is provided with a molten metal. Is caused to flow down and adhered, so that the recovery of the molten metal becomes extremely easy.

Furthermore, in the method and apparatus for processing a workpiece according to the sixth and seventh aspects,
A shield box that moves following the plasma torch is provided, and this shield box is provided on both sides so as to cover the cut point of the workpiece, so that the workpiece can be covered locally with a shielding gas other than oxygen. Thus, it is not necessary to cover the entire structure with the shielding gas, so that the shielding gas can be saved.

Further, in the method of processing a workpiece according to claim 8, the workpiece is placed in an atmosphere gas other than oxygen or in a vacuum, and the workpiece is irradiated with a laser beam to form a hole. By performing laser processing such as cutting and the like, the molten metal melted by the laser beam irradiation can flow down to the cut back side of the workpiece and adhere to the cut back side to be easily collected.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a workpiece processing apparatus according to the present invention.

FIG. 2 is a view showing a state of adhesion of a molten metal when a 70 mm thick SUS plate is plasma-arc cut using the processing apparatus shown in FIG. 1;

FIG. 3 is a schematic configuration diagram showing a second embodiment of the workpiece processing apparatus according to the present invention.

FIG. 4 is a schematic configuration diagram showing a third embodiment of a workpiece processing apparatus according to the present invention.

FIG. 5 is a schematic configuration diagram showing a fourth embodiment of a laser processing apparatus for performing the processing method of a workpiece according to the present invention.

FIG. 6 is a diagram showing a blanket module in the International Thermonuclear Experimental Reactor.

FIG. 7 is a schematic configuration diagram illustrating a cutting disassembly structure such as a blanket module;

FIG. 8 is a configuration diagram showing a problem in plasma arc cutting of a conventional structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Plasma torch 11 Insulator 12 Electrode 13 Torch nozzle 14 Working gas passage 15 Swirler 16 Nozzle mouth (orifice) 17 Plasma arc 18 Nozzle cap 19 Assist gas passage 20 Swirler 22 Work (workpiece, structure) 23 Molten metal 24 Anode point (Cathode point) 25 Cut surface 28 Thin plate 30 Shield box 31 Connecting arm 33 Laser scanning optical system 34 Condensing lens

Claims (8)

[Claims] When a workpiece is placed in an atmosphere gas other than oxygen or in a vacuum, and the workpiece is cut by a plasma arc from a plasma torch, a working gas and an assist gas for the plasma torch other than oxygen are used. Cutting the work in the atmospheric gas or vacuum using the gases described above, and collecting and collecting the molten metal on the cut back surface side of the work. 2. A plasma torch is provided to be inclined with respect to a vertical surface including a cutting direction, and when a workpiece is cut with a plasma torch by a plasma arc, a molten metal is attached to a scrap-side cut back surface of the workpiece to be recovered. The method for processing a workpiece according to claim 1. 3. When a thin plate is provided on the cut back side of the workpiece and the workpiece is cut by a plasma arc with a plasma torch,
2. The method for processing a workpiece according to claim 1, wherein the molten metal is adhered to and recovered from the thin plate. 4. A workpiece is placed in an atmosphere gas other than oxygen or in a vacuum, and a plasma torch for cutting the workpiece with a plasma arc is provided facing the workpiece, and the plasma torch is operated by being ejected from a torch nozzle. A processing apparatus for a workpiece, wherein a gas other than oxygen is used as a gas and an assist gas ejected from a nozzle cap. 5. The apparatus for processing a workpiece according to claim 4, wherein the workpiece is provided with a thin plate on a side opposite to the plasma torch. 6. A pair of shield boxes that operate following a plasma torch, and the shield boxes are installed to face each other with a workpiece interposed therebetween, and the workpiece is cut with a plasma arc from a plasma torch by plasma arc cutting. While locally covering the cut portion of the workpiece with the shielding gas, the workpiece is cut using a gas other than oxygen as the working gas and the assist gas of the plasma torch, and the molten metal is adhered to the cut back side of the workpiece. A method of processing a workpiece, wherein the method is to collect the workpiece. 7. A pair of shield boxes so as to sandwich a workpiece, one of the shield boxes is fixed to a plasma torch, and both shield boxes are connected by a connecting arm so as to be able to follow the plasma torch. A workpiece other than oxygen is used for the working gas and the assist gas of the plasma torch while the cut portion of the workpiece is locally covered with the shielding gas in the shield box. Processing equipment. 8. When a workpiece is placed in an atmosphere gas other than oxygen or in a vacuum, and the workpiece is irradiated with a laser beam from a laser device to perform laser processing, the workpiece is placed in the atmosphere gas or vacuum. A drilling or cutting operation using a laser beam, and collecting and collecting the molten metal generated by the laser beam irradiation on the irradiation back side of the workpiece.