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EP-4736583-A1 - METHOD AND DEVICE FOR COATING A WORKPIECE SURFACE

EP4736583A1EP 4736583 A1EP4736583 A1EP 4736583A1EP-4736583-A1

Abstract

The invention relates to a method for coating a workpiece surface (133), in which an atmospheric plasma beam (26) is generated by means of a plasma nozzle (2), a coating material is supplied to the generated plasma beam (26) and the plasma beam, with the coating material, is directed to the workpiece surface (133) to be coated, wherein the coating material is supplied to the generated plasma beam (26) in that a filament (34) is supplied to the generated plasma beam (26), said filament containing or consisting of the coating material. The invention also relates to a device (100, 200, 300, 400) for coating a workpiece surface (133), having a plasma nozzle (2) which is designed to generate an atmospheric plasma beam (26), wherein the plasma nozzle (2) has a nozzle opening (6) from which the plasma beam (26) exits during operation, and having a filament supply element (124) which is arranged and designed to supply a filament (34) to the generated plasma beam (26) during operation, and to a use of the device (100, 200, 300, 400).

Inventors

  • Buske, Magnus
  • GEHRA, Raphael
  • HERMANN, PHILIPP
  • SCHLEE, Hassan Orle Ahmad
  • Ben Salem, Dhia

Assignees

  • Plasmatreat GmbH

Dates

Publication Date
20260506
Application Date
20240626

Claims (14)

  1. 1. Method for coating a workpiece surface (133), in particular using a device (100, 200, 300, 400) according to one of claims 7 to 12, in which an atmospheric plasma jet (26) is generated by means of a plasma nozzle (2), in which a coating material is supplied to the generated plasma jet (26), and in which the plasma jet (26) with the coating material is directed onto the workpiece surface (133) to be coated, characterized in that the coating material is supplied to the generated plasma jet (26) by supplying a filament (34) containing or consisting of the coating material to the generated plasma jet (26).
  2. 2. Method according to claim 1, characterized in that the plasma jet (26) is generated by means of electrical discharges in a working gas, in particular by means of high-frequency high-voltage discharges, in particular between at least two electrodes of the plasma nozzle.
  3. 3. Method according to claim 1 or 2, characterized in that the filament (34) contains at least one plastic, is based on a plastic or consists of a plastic.
  4. 4. Method according to one of claims 1 to 3, characterized in that the filament (34) contains additives which are preferably embedded in a polymer matrix.
  5. 5. Method according to one of claims 1 to 4, characterized in that the filament (34) is guided into the plasma nozzle (2), in particular in the region of a nozzle opening (6) of the plasma nozzle (2), or that the filament (34) is fed to the plasma jet (26) outside the plasma nozzle (2), in particular in the region in front of a nozzle opening (6) of the plasma nozzle (2).
  6. 6. Method according to one of claims 1 to 5, characterized in that the filament (34) is cooled before entering the plasma jet (26), in particular before entering the plasma nozzle (2).
  7. 7. Device (100, 200, 300, 400) for coating a workpiece surface (133), with a plasma nozzle (2) which is designed to generate an atmospheric plasma jet (26), wherein the plasma nozzle (2) has a nozzle opening (6) from which the plasma jet (26) emerges during operation, and with a filament feed (124) which is arranged and designed to feed a filament (34) to the plasma jet (26) generated during operation.
  8. 8. Device according to claim 7, characterized in that the plasma nozzle (2) is designed to generate the plasma jet (26) by means of electrical discharges in a working gas, in particular by means of high-frequency high-voltage discharges, in particular between at least two electrodes of the plasma nozzle (2).
  9. 9. Device according to claim 7 or 8, characterized in that the filament feed (124) has a receptacle (112) for a filament supply (113), in particular for a filament spindle.
  10. 10. Device according to one of claims 7 to 9, characterized in that the filament feed (110) is designed to guide the filament (34) into the plasma nozzle (2), in particular in the region of the nozzle opening (6) of the plasma nozzle (2).
  11. 11. Device according to one of claims 7 to 10, characterized in that the filament feed (110) has a filament transport device (116) which is designed to feed the filament (34) to the generated plasma jet at a predetermined speed.
  12. 12. Device according to one of claims 7 to 11, characterized in that the filament feed (110) has a cooling device (122) which is designed to cool the filament (34) and/or a part of the filament feed (110) in the region of the plasma nozzle (2).
  13. 13. Device according to one of claims 7 to 12, characterized in that the device (100, 200, 300, 400) has a control device which is designed to control the operation of the device (100, 200, 300, 400), in particular the filament feed (110) and/or the plasma nozzle (2).
  14. 14. Use of the device (100, 200, 300, 400) according to one of claims 7 to 13 for coating a workpiece surface (133).

Description

Method and device for coating a workpiece surface The present invention relates to a method for coating a workpiece surface, in which an atmospheric plasma jet is generated by means of a plasma nozzle, in which a coating material is supplied to the generated plasma jet and in which the plasma jet with the coating material is directed onto the workpiece surface to be coated. The present invention further relates to a device for coating a workpiece surface and the use of the device. Various atmospheric coating processes are known from the state of the art. In cold gas spraying, coating material in powder form is applied to the workpiece surface to be coated at very high speed. The powders used here have very small particle sizes, some of which are respirable, and therefore require a high level of safety. Furthermore, the gases (such as helium) used for the supersonic gas jets used in these processes are quite expensive. In addition, this process requires a certain ductility of the powder particles and the workpiece surface to be coated, which results in material limitations. In atmospheric plasma spraying, powder is introduced into a high-temperature plasma generated by DC discharge or low-frequency discharge and directed at the workpiece surface to be coated. The powders in turn require safety precautions when handling. In addition, the high temperatures are not suitable for certain coating materials and workpieces, which in turn results in material limitations. Coating processes using an atmospheric plasma jet are also known, which is generated by high-frequency high-voltage discharges. Compared to plasma spraying, these processes work at lower temperatures and are therefore also suitable for more temperature-sensitive workpieces. However, the liquids, gases or powders used as precursors require very high safety precautions. In addition, the application rates in such a process are quite low, so that it is particularly suitable for thin layer thicknesses. In addition, feeding a precursor in powder form requires a sophisticated transport mechanism to achieve uniform and reliable powder feeding, making the coating equipment more complicated and expensive. WO 2011/042459 A1 discloses an atmospheric pressure plasma process in which a precursor in a gaseous, liquid or solid, powdery state is introduced into an atmospheric plasma jet and a coating is deposited on a workpiece surface in this way. Such precursors may require very high safety precautions. At the same time, a sputter electrode is used as the inner electrode of the plasma nozzle, from which particles are released by the high-frequency discharges between the sputter electrode and a counter electrode, which are embedded in the coating. Against this background, the present invention is based on the object of providing a method and a device for coating a workpiece surface, which reduce or overcome one or more of the aforementioned disadvantages of the methods from the prior art. In particular, the invention is based on the object of providing a method and a device for coating a workpiece surface, which is also suitable for temperature-sensitive workpiece surfaces are suitable, lower require security requirements and/or enable higher order rates. The above-mentioned object is achieved according to the invention by a method for coating a workpiece surface, in which an atmospheric plasma jet is generated by means of a plasma nozzle, in which a coating material is fed to the generated plasma jet and in which the plasma jet with the coating material is directed onto the workpiece surface to be coated, wherein the coating material is fed to the generated plasma jet by feeding a filament that contains or consists of the coating material to the generated plasma jet. In this way, a coating of a workpiece surface is achieved with a lower risk potential for the operator of the coating device. In addition, relatively high deposition rates and thus high layer thicknesses can be achieved with this method. In the process, an atmospheric plasma jet is generated using a plasma nozzle. By using an atmospheric plasma jet, negative pressure environments can be dispensed with. An atmospheric plasma jet is understood to be a plasma jet that is operated in the range of atmospheric pressure, i.e. in particular when exiting the plasma nozzle, for example with a slight overpressure, it enters an environment in the range of atmospheric pressure. The plasma jet can, for example, have a pressure in the range of +/- 300 mbar, preferably +/- 200 mbar around the surrounding atmospheric pressure. The use of a plasma jet generated with a plasma nozzle also allows a targeted impact on the workpiece surface to be coated. In particular, the coating can be applied in a targeted manner to the desired areas of the workpiece surface. Furthermore, the thickness of the coating can be easily adjusted in this way. Furthermore, the plasma nozzle can be moved relative to the workpiece surface, for e