WO2006079336A1

WO2006079336A1 - Method and device for processing object surfaces with an electrically conductive molten material, which is removed or moved by a high-frequency field

Info

Publication number: WO2006079336A1
Application number: PCT/DE2006/000188
Authority: WO
Inventors: Jürgen KNORR; Wolfgang Lippmann; Anne-Maria Reinecke; Regine Wolf; Roland Rasper
Original assignee: Technische Universität Dresden
Priority date: 2005-01-31
Filing date: 2006-01-30
Publication date: 2006-08-03
Also published as: DE102005005707B3

Abstract

The invention relates to a method and device (1) for processing object surfaces (5) by using a radiation (4) which is oriented toward the object surface (5) to be processed and forms a molten material (6) in the area of action of the radiation (4). The aim of the invention is to substantially reduce a release of uncontrollable dust, particularly radioactive substances, and to be able to ensure a final disposal in a cost-effective manner. In addition, the invention aims to remove holes, bites, recesses and other defects in the object surfaces (5). To this end, the molten material (6), in an electrically conductive manner and on the object surface (5), is removed from the object surface (5) by a high-frequency field (8) that surrounds and covers the molten material (6), and/or is moved on the object surface (5).

Description

METHOD AND DEVICE FOR PROCESSING OBJECT SURFACES WITH AN ELECTRICALLY CONDUCTIVE MELT THROUGH OR HAVING A HIGH FREQUENCY FIELD

description

The invention relates to a method and a device for processing object surfaces by means of a radiation, which is directed to the object surface to be processed, and there generates a melt in an area of action. The method can be used for processing, in particular for the decontamination of objects with electrically conductive surfaces, for the decontamination of objects with non-electrically conductive surfaces, for the production of very pure material compositions and for the production of precisely defined material portions.

A generic device is described in the publication GB 2 264 887 A. The device includes a laser whose laser beam is intended for processing material. The machining refers to cutting and drilling materials. Due to the interaction of a permanent or pulsed magnetic field with a melt through which a current flows, a force-a Lorentz force-is generated which acts on the melt, whereby the melt can detach from the object surface and be displaced from the dissolution point to another location ,

One problem is that during the processing of the material, the material must be electrically conductive so that a relatively high current can flow through the material in order to generate the Lorentz force with the current flowing through the material and the magnetic field perpendicular thereto. which can then move and transport the melt out of the surface area to be processed. Only by the use of electricity within the material, a shift in the surface melt can be achieved, but this represents a high energy consumption.

A method for processing a workpiece with a laser beam and an associated device are known in the printing DE 197 32 008 Al described. In this case, a moving through the workpiece melt is generated by means of a focused laser beam. With a given relative movement between the laser beam and the workpiece, the melt gets into flow. In order to shape and stabilize the flow, for example to prevent droplets from being melted and, during welding operations, to prevent poor surface quality and to travel at high relative speed, a magnet is provided which generates a magnetic field in the area of the melt. The magnetic field is directed to exert a force on the melt that acts toward the melt base. By an electric current, which is passed through the melt, the effect of the magnetic field can be amplified and modified.

One problem is that the use of the magnetic field is ultimately aligned with the fate of the melt in the region of the workpiece. Gaps in the workpiece with the melt produced are created and closed. Also, the entire workpiece is involved in the magnetic field.

Machining of the surface areas with removal of the melt away from the surface, preferably for decontamination of surfaces with removal of the contaminated surface areas, is not provided for in the above two methods and devices.

A process for treating radionuclide contaminated surfaces of equipment is described in document RU 2 120 677. The method includes coating the contaminated surface with a Final material, wherein the method is performed by treating the surface with an intense heat treatment using a laser radiation.

The sealing material is melted and a glass-hard coating is formed on top of the surface by the thermal radiation. The radionuclides remain within the formed coating, concrete and metal surfaces can be treated by the process.

Furthermore, a method and an associated device for decontamination of metal bodies is described in document FR 2 673 389, in which the metal objects are arranged in a housing which contains a lower-energy laser beam generating device - a laser - and a shell which receives the laser beam , contains. The procedure is used for the decontamination of needles and scalpels in hospitals.

Also, a method for cleaning metal surfaces by means of laser radiation in the document RU 2 104 846 is described. With the laser radiation, a radioactive decontamination of metal structures and pipes of nuclear power plants takes place during operation.

The process is carried out by means of the laser radiation on the surfaces treated with pulsed power, wherein an energy density is present on the processing object surface for evaporation of the refractable bonds of the material with removal of the evaporation products from the processing object surface by means of a gas flow. Furthermore, a method and a device for cleaning metal surfaces by means of pulsed laser radiation having two different wavelengths is described in the document EP 1 340 556 A2. In this case, a base frequency and a harmonic frequency of a: laser beam in the order of 1 to 40 ns in simultaneous or spatial superposition of pulse trains and different energy intensity variations is used. The process can be used to remove radioactive residues. By means of the pulsed laser radiation, the metal surface is heated to such an extent that the thermally induced tensions within the surface cause the surface to flake off. In this sense, the process should also be assigned to the mechanical removal process. One problem is that even in this case difficult to control radioactive dusts arise.

In the case of the processes, which are essentially mechanical application processes, there is the problem that a technologically induced generation of dust is present. The resulting dusts are first treated via special process steps, i. conditioned before they can be transported and stored. If these dusts are released, in turn, extensive decontamination work is required.

One problem is that it causes large amounts of radioactive dust that is difficult to control.

The invention is based on the object of specifying a method and a device for processing object surfaces which are designed so that a free Settlement of uncontrollable. Dust in particular radioactive substances is substantially reduced and a final disposal can be ensured inexpensively. In addition, holes, cracks, depressions or other defects in the object surfaces should be eliminated.

The object is solved by the features of claims 1 and 15. In the method for processing object surfaces by means of radiation which is directed onto the object surface to be processed and generates a melt there in the effective area of the radiation, according to the characterizing part of patent claim 1, the melt becomes electrically conductive and on the object surface through the high-frequency field surrounding and detecting the melt is released from the object surface and / or moved on the surface of the object.

In this case, the melt on the object surface can be shaped by the high-frequency field surrounding and detecting the melt to at least one melt drop detachable from the object surface and / or movable on the object surface.

The melt, and in particular the melt drops, can be transported, displaced or spun to designated locations for eliminating defects and / or for geometrically changing the object surfaces on the object surface.

The melt on the object surface can also be lifted by the high-frequency field surrounding and detecting the melt and formed into at least one melt droplet dissolving from the object surface, which can be moved. Dάe field strength and the frequency of the high frequency field in the form of an alternating electromagnetic field can be adapted to the size and volume of the melt to be transported and / or melt drops.

The high frequency coil can be assisted in moving, shifting, centrifuging the melt and the melting droplets of at least one switchable stationary electromagnetic field, wherein a guideway and a final position by the predetermined stationary electromagnetic field or other predetermined electromagnetic fields can be adjusted.

The alignment of the stationary electromagnetic field with the associated predetermined magnetic flux density can be adjusted when the melt drops are thrown to the object surface with a specific inclination to the given guide track, the melt drips.

The effective range of the radiation, the radio-frequency field and optionally the stationary electromagnetic field can be formed to form a stream of liquid droplets arranged in juxtaposition and moved as a unit relative to the object surface to be processed.

As a processing of the object surfaces, among other things, a removal of a surface layer, a smoothing of the surface and / or a removal of defects, on or in the object surface can be performed. As object surfaces, the surfaces of pure metal, alloys, metals with niσhtmetallisσben shares and metals with coatings and surface layers, the z .B. surfaces contaminated and associated with radioactive material, but also the surfaces of other objects and materials, eg. Concrete, glass or semiconductor structures, are determined, wherein the object surface to be machined associated melt is or is brought into a state of a predetermined range of the electrical conductivity or in a state of a predetermined electrical conductivity value.

In the device for processing object surfaces by means of radiation which is directed onto the object surface to be processed and generates a melt there in an area of action of the radiation, according to the characterizing part of claim 15, the melt is electrically conductive and at least above the region of the melt a high-frequency coil surrounding the area of action of the radiation and detecting the melt, the radio-frequency coil having: a high-frequency field, which exerts a coalescing force on the melt, whereby the melt is detachable from the object surface and / or movable on the object surface.

In this case, the high-frequency field can have a dimensioning, in particular with respect to field strength and frequency, that at least one separate melting droplet detaching from the object surface is formed. The radio-frequency coil can be surrounded by at least one electromagnetic coil to form a supporting stationary electromagnetic field, wherein the melt or the melt droplets are in detachable connection with the stationary electromagnetic field.

The energy radiation can be generated by means of a laser, wherein a laser beam is directed onto the object surface, on which absorption of the radiation generates the electrically conductive melt.

The laser may be an Nd: YAG laser or a CQ2 laser or a diode laser.

The high frequency field may have a frequency of the order of about 1.0 MHz.

The electromagnetic coil can be arranged laterally inclined, wherein the melt or the melt droplets can be thrown out of the area of action of the radiation guided individually or similar to a liquid jet and can be taken up and disposed of in assigned containers.

The invention opens up the possibility that a contact-free transport of the melt of. the solid object surface can be carried away or on the object surface, including surfaces of concrete and glass and semiconductor structures are included. In this process, an electrically conductive melt is generated in one working step by high-energy radiation, which can then be moved without contact, displaced or removed from the starting point. The invention also makes it possible for both a radioactive object surface to be able to be removed in a technological working method and for the waste product to be conditioned in such a way that it is largely suitable for disposal.

In the present method, the local melting of the object surface may be effected by means of laser radiation or other energy input processes, e.g. by means of electron beams or inductive heating.

The removal and treatment of the melt from an object surface takes place in the following steps:

Formation of an electromagnetic alternating field of a high-frequency field in the region of the melt, thereby inducing a flow of current in the melt,

- which causes the build-up of a secondary electromagnetic field,

- the interaction between the secondary electromagnetic field and the primary electromagnetic field creates a force on the melt,

- The melt is thereby pulled together and can be moved or accelerated as melt droplets or similar to a liquid jet in a defined direction.

The defined direction may be assisted by the stationary electromagnetic field and may also refer to a different location on the object surface, for example to defects to be eliminated, or to a container or space remote from the object surface for disposal of the melt. During processing, the surface of the object can be protected from oxidation by means of inert gas or inert gas or vacuum.

The other advantages of the invention are no dust, in particular of radi oaktive dusts, a high removal rate with low attenuation of radioactive substances, a final end product endowed and a good automation.

The invention will be explained in more detail using an exemplary embodiment by means of several drawings.

1 is a schematic representation of the inventive device by means of a radiation which is generated by a laser in the form of a laser beam, and by means of a high-frequency coil,

2 shows a schematic representation of the final ablation of a melting drop from the range of magnetic fields in the multiphase system-suction formation, drop formation, centrifuging-

3 is a schematic representation of the above the melt arranged high frequency coil without laser beam,

4 is a schematic representation of the melt suction through the high-frequency coil in the high-frequency field according to FIG. 3, FIG. Fig. 5 is a schematic representation of the outline of a

Melt drop from the melt suction in the high frequency field of FIG. 4 and formation of an independent melting droplet and

Fig. 6 is a schematic representation of the high frequency field with a superimposed stationary electromagetic field and a guided centrifuging of the melt drop by interaction of both magnetic fields.

The FIGS. 1 and 2 are considered together. In Fig. 1 is a schematic representation of a device 1 for processing an object surface 5 in particular for decontamination of the object surface 5 by means of a radiation 4, which is directed to the ablated object surface 5 and there generates a melt 6 in the area of action of the radiation 4.

According to the invention, the melt 6 is electrically conductive and, as shown in FIGS. 2 to 5, above the region of the melt 6 at least one radio frequency coil 7 comprising the effective region of the radiation 4 is arranged, the high frequency coil 7 having a high frequency field 8 on the melt 6 exerts a melt suction 9 and at least one separate from the object 2 abläsenden melt drops IQ forms in the tear 13.

The high-frequency coil 7 may, as shown in Fig. 6, of. be surrounded at least one electromagnetic coil 11 to form a stationary electromagnetic field 12, wherein the Sσhmelztropfen 10 with the stationary magnetic field 12 in detachable connection.

The radiation is generated by means of a laser 3, as shown in FIG. 1, a laser beam 4 being directed onto the object surface 5, and the heat generated on the object surface 5 producing the electrically conductive melt 6.

As laser 3, an Nd: YAG laser or a CO 2 laser or a diode laser may be provided.

During processing, the object surface 5 can be protected from oxidation by means of inert gas or inert gas or vacuum.

The high-frequency field 8 preferably has a frequency of approximately 1.0 MHz.

The electromagnetic coil 11 can be arranged laterally inclined, not shown in FIG. 6, whereby the melting drops 10 are ejected from the effective region of the radiation 4 individually or as a liquid jet in the repelling direction 14 and can be disposed of by means of an associated container 15.

In the method according to the invention for processing object surfaces by means of a radiation 4, which is directed onto the object surface 5 to be processed, and there generates a melt 6 in the area of action of the radiation 4, the melt 6 becomes electrically conductive and is deposited on the object surface. Surface 5 raised by a surrounding the melt 6 and detecting high frequency field 6 and formed to at least one of the object surface 5 itself dissolving melt droplets 10, which is lifted from the high frequency field 6 out.

The radio-frequency coil 7 can be assisted for guided movement or for ejection of the melt drops 10 from a switchable stationary electromagnetic field 12 in the form of a guideway.

The direction of the stationary electromagnetic field 12 with associated magnetic flux density is adjustable to the object surface 5 with a certain inclination to the predetermined discharge / removal of the melt 6 or the melt drops 10.

The area of action of the radiation 4, the high-frequency field 8 and the electromagnetic field 12 can be formed from melt drops 10 to form a liquid jet and can be displaced together in the form of a unit on the object surface 5.

As object 2 pure metal, alloys, metals with non-metallic parts as well as metals with coatings and O- berflächenschichten, for example, with radioactive constituents contaminated and connected metal surfaces, set. But also the object surfaces of objects made of concrete, reinforced concrete, glass and semiconductor structures can be processed by the method and the device 1 according to the invention, wherein the melt 6 in each case the state of a predetermined electrical conductivity or a predetermined NEN conductivity value has or transferred to an electrically conductive state.

The device 1 according to the invention can be designed as a device that can be used conveniently.

The method and the device according to the invention can be used in many areas and are by no means limited to decontamination.

Another application example is the production of very pure material compositions, wherein the entire process takes place without contact. Likewise, the method can serve for the production of precisely defined material portions.

LIST OF REFERENCE NUMBERS

1 facility

2 object 3 lasers

4 radiation

5 object surface

6 melt

7 high frequency coil 8 high frequency field

9 melt suction

10 melting drops

11 electromagnetic coil

12 stationary electromagnetic field 13 Demolition of the melt drop

14 Abstoßriσhtung the melt drop

15 container

Claims

claims

1. A method for processing object surfaces by means of radiation, which is directed to the object surface to be processed and there generates a melt in the effective range of the radiation, characterized in that the melt (6) is electrically conductive and on the object surface (5) by a high-frequency field (8) surrounding and detecting the melt (6) is released from the object surface (5) and / or moved on the object surface (5).

2. The method according to claim 1, characterized in that the melt (6) on the object surface (5) lifted by the high-frequency field (8) and optionally guided.

3. The method according to claim 1 or 2, characterized in that the melt (6) on the object surface (5) to at least one of the object surface (5) detachable and / or on the object surface (5) movable melt drips (10) is formed.

4. Method according to any preceding claim, characterized that the melt (6) and the melt drop (10) are transported, displaced or hurled to corresponding locations to eliminate defects and / or to geometrically change the surface of the object (5) on the object surface (5).

5. The method according to any preceding claim, characterized in that the field strength and the frequency of the high-frequency field (8) of the size usid / or the volume of the melt droplets to be transported (10) are adjusted.

6. The method according to any preceding claim, characterized in that the high-frequency coil (8) during movement, displacement, centrifuging of the melt (6) and the melt drops (10) is supported by at least one switchable stationary electromagnetic field (12), wherein a guideway and a final position by the stationary electromagnetic field (12) or other predetermined electromagnetic fields are set.

7. The method according to any preceding claim, characterized in that the orientation of the stationary electromagnetic field

(12) with associated magnetic flux density when centrifuging the melt droplets. (10) to the object surface (5) directed with a certain inclination to the predetermined guide path of the melt drops (10) is adjusted.

8. Method according to any preceding claim, characterized in that the effective range of the radiation (4), the high-frequency field (8) and optionally the electromagnetic field (12) for forming a successive melt droplets (10) existing liquid jet is formed and moved as a unit relative to the object surface (5) ,

9. The method according to any preceding claim, characterized in that as object surfaces (5) the surfaces of pure metal, alloys, metals with non-metallic components and metals with coatings and Oberflächenschich- th, which also contaminated with radioactive constituents and connected surfaces , but also of other objects and materials made of concrete, reinforced concrete, glass or semiconductor structures are defined, wherein the respective resulting melt (5) becomes electrically conductive.

10.A method according to any preceding claim, characterized in that as radiation (4) for the local melting of the object surface (5) laser radiation or other Energieein- tragungsprozesse - by electron beams or by inductive heating - are used.

11.A method according to any preceding claim, characterized in that the treatment of the melt (6) on the object surface (5) takes place in the following steps: - construction of an alternating electromagnetic field - a high-frequency field (8) - in the region of the melt (6),

Induction of a current flow in the melt (6),

- construction of a secondary electromagnetic field, - interaction between the secondary electromagnetic field and the primary alternating electromagnetic field (8) to generate a force on the melt (6),

- Concentration of the melt (6), - Movement of the melt (6), the melt drop (10) or the liquid jet in a defined direction (14).

12.A method according to any preceding claim, characterized in that a contactless transport of the melt (6) from the solid object surface (5) directed away or on the object surface (5) is performed, which also surfaces of concrete, glass or semiconductor structures are included and wherein in one step by high-energy radiation, an electrically conductive melt (6) is generated, which is then moved from the starting point of the object surface (5) without contact, moved, removed.

13.Verfahren according to any preceding claim, characterized in that the defined direction to another position on the

Object surface (5), on defects to be removed, and / or on a container removed from the object surface (5)

(15) or place for disposal of the melt (6) is obtained.

14.Verfahren according to any preceding claims 1 to 13, characterized in that during the processing, the object surface (5) by means of inert gas or inert gas or vacuum is protected from oxidation.

15.Einrichtung for processing of object surfaces by means of radiation, which is directed to the object surface to be processed and there generates a melt in the region of action of radiation, characterized in that the melt is conductive and above the region of the melt (6) at least one of the effective range the high-frequency coil (7) surrounding the radiation (4) and the melt (6) is arranged, wherein the high-frequency coil (7) has a high-frequency field (8) which exerts a compressive force on the melt (6), whereby the melt (6 ) is detachable from the object surface (5) and / or movable on the object surface (5).

16.Einrichtung according to claim 15, characterized in that the high-frequency field (8) has a dimensioning with respect to field strength and frequency that at least one separate, from the object surface (5) detaching melt droplets (10) is formed.

17.Einrichtung according to claim 15 and / or 16, characterized in that the high-frequency coil (7) of at least one elec- tromagnetspule (11) for forming a supporting stationary electromagnetic field (12) is surrounded, wherein the melt (6) or the melt drops (10) with the stationary electromagnetic field (12) are detachably connected.

18.Einrichtung according to any preceding claim, characterized in that the radiation by means of a laser (3) is generated, wherein a laser beam (4) is directed to the object surface (5) on which the resulting heat is an electrical. conductive melt (6) is formed.

19.Einrichtung according to any preceding claim, characterized in that as laser (3) an Nd: YAG laser or a CO2 laser or a diode laser are provided.

20. Setup after, a previous one. Claim., Characterized in that the high frequency field (8) has a frequency in the order of magnitude of about 1.0 MHz.

21.Einrichtung according to any preceding claim, characterized in that the electromagnetic coil (11) is arranged laterally, inclined, wherein the melt (6) or the melt drops (10) from the sphere of action of the radiation (4) individually or similar in shape guided centrifuged a liquid jet and in associated containers (15) are receivable and disposable.