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Verfahren zur definierten Modifizierung von Oberflaechen eines Werkstuecks

Method for defined modification of surface of a workpiece, which is formed from a metallic material formed in an environmental condition on the surface of oxide layers, by irradiating an area of the workpiece surface with laser radiation
 
: Rechner, R.; Jansen, I.; Beyer, E.

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Frontpage ()

DE 102009054394 A: 20091117
DE 102009054394 A: 20091117
B23K0026
German
Patent, Electronic Publication
Fraunhofer IWS ()

Abstract
(A1) Die Erfindung betrifft ein Verfahren zur definierten Modifizierung von Oberflaechen eines Werkstuecks, das aus einem bei Umgebungsbedingungen an der Oberflaeche Oxidschichten bildenden metallischen Werkstoff gebildet ist. Bevorzugt kann das Verfahren an Werkstuecken, die aus Aluminium oder einer Aluminiumlegierung gebildet sind, beispielsweise auch bei Titan und seinen Legierungen eingesetzt werden. Bei dem erfindungsgemaessen Verfahren wird zumindest ein Bereich der Oberflaeche eines Werkstuecks mit von einer Laserlichtquelle in gepulster Form emittierter Laserstrahlung bestrahlt, um dabei an der Oberflaeche vorhandene organische und anorganische Verunreinigungen oder eine solche Schicht durch Ablation zu entfernen. Im Anschluss daran wird auf dem so behandelten Bereich der Oberflaeche von einer im cw-Mode betriebenen Laserlichtquelle Laserstrahlung in einer Sauerstoff enthaltenden Umgebung so eingesetzt, dass an der Oberflaeche eine Temperatur von mindestens 250°C und maximal die Schmelztemperatur des metallischen Werkstoffs erreicht oder eingehalten wird. Dabei wird eine definierte Oxidschicht auf der Oberflaeche ausgebildet. Hierfuer wird die Leistungsdichte im Brennfleck der gepulsten Laserstrahlung zur Entfernung der organischen und anorganischen Verunreinigungen oder einer Schicht groesser gewaehlt, als bei der kontinuierlichen Bestrahlung im cw-Mode. Der emittierte Laserstrahl und das Werkstueck werden dabei relativ zueinander bewegt.

 

DE 102009054394 A1 UPAB: 20110609 NOVELTY - The method for defined modification of surface of a workpiece, which is formed from a metallic material formed in an environmental condition on the surface of oxide layers, comprises irradiating an area of the surface of the workpiece with laser radiation emitted in pulsed form from a laser light source in order to remove organic and inorganic impurities present on the surface or a layer through ablation and in connection to the area of the surface of the workpiece to be irradiated with laser radiation from the laser light source operated in continuous wave-mode. DETAILED DESCRIPTION - The method for defined modification of surface of a workpiece, which is formed from a metallic material formed in an environmental condition on the surface of oxide layers, comprises irradiating an area of the surface of the workpiece with laser radiation emitted in pulsed form from a laser light source in order to remove organic and inorganic impurities present on the surface or a layer through ablation and in connection to the area of the surface of the workpiece to be irradiated with laser radiation from the laser light source operated in continuous wave-mode in an oxygen containing environment such that a temperature reaches 250 degrees c or maximum of the melting temperature of the metallic material and at the same time defined oxide layer is formed on the surface, where the power density is greater in the continuous radiation in the continuous wave-mode at the focal point of the pulsed laser radiation to remove the organic and inorganic impurities or a layer and at the same time the emitted laser radiation and the workpiece are relatively movable from one another. The laser light source is introduced through pulsed switching and is operable in continuous wave-mode. The metallic material of the workpiece is not removed during the removal of impurities or the layer. The temperature is measured for a regulation of the laser light source and/or the deflection of the emitted laser radiation. Oxygen or oxygen containing process gas is supplied to the irradiated portion of the workpiece surface with laser radiation or the oxygen or oxygen containing process gas mixture is supplied in a closed chamber during formation of a defined oxide layer. The ablation products are discharged during removal of impurities or the layer through a suction and/or by means of a process gas supplied in cross flow manner. The electro magnetic radiation is used with a wave length of more than 750 nm. The application of adhesion promoter is carried out for a corresponding integral connection of the workpiece with a further workpiece in the formation of the defined oxide layer. A homogeneous oxide layer and/or a structured oxide is formed in a defined form over the irradiated surface area of the workpiece with the laser radiation over the entire surface. The workpiece is modified on the surface formed from aluminum or aluminum alloy. USE - Method useful for defined modification of surface of a workpiece. ADVANTAGE - The method ensures simple modification of surface of a workpiece with improved strength and stability.

: http://publica.fraunhofer.de/documents/N-174794.html