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1315 |
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Monday, June 02, 2008, Room 05 2:20 PM New Equipment 2 Latest developments in thermal spray equipment, modern multiple arc plasma guns, optimized powder feeder, new vacuum processes |
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A new way in HVOF technology ? CFD optimized topgun® airjet for powder and wire |
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Christian Rupprecht* / Chemnitz University of Technology, Germany Bernhard Wielage / Chemnitz University of Technology, Germany Gerd Paczkowski/ Chemnitz University of Technology, Germany Gerd Weissenfels/ IBEDA Sicherheitsgeräte und Gastechnik GmbH & Co. KG, Germany Rolf Menzen/ IBEDA Sicherheitsgeräte und Gastechnik GmbH & Co. KG, Germany Heinz Ulrich Bernhardt/ IBEDA Sicherheitsgeräte und Gastechnik GmbH & Co. KG, Germany Michael Runkel/ IBEDA Sicherheitsgeräte und Gastechnik GmbH & Co. KG, Germany |
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The thermal spray industry requires universal and economical HVOF systems for the production of high quality coatings with high deposition efficiencies. In the last years classic HVOF guns have been adapted insufficiently to these requirements. In this paper it is shown how modern numeric simulation and new inventions in gas safety engineering enable the development of a spray-system for powder and wire feedstock that is optimised especially for the needs of the market. The new TOPGUN® AIRJET (IBEDA) is equipped with an air cooled ?de Laval? like nozzle. The optimised expansion of the gas leads to high gas and particle velocities as well as to low flame and particle temperatures. Advantages of the TOPGUN® AIRJET are high coating quality, low energy consumption (propane, ethane), utilisation of powder or wire and efficient air cooling of the thermally stressed nozzle parts. Additionally, as a result of the axial powder injection the free jet divergence and the nozzle wear are minimised. By variation of the powder gas flow the dwell time of the particles inside the flame can be influenced in a wide range. In this way the thermal stress of the spraying material can be optimised in order to avoid the fusing of particles. As an example WC/Co 88/12 coatings are presented and compared to coatings sprayed with a standard HVOF system of the 3rd generation. To show the workability of solid and cored wires different 316L coatings are produced and tested in comparison to standard HVCW coatings. |