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Verfahren zum Schmelzschneiden von Werkstuecken mit Laserstrahlung

Fusion cutting of workpiece with laser beam, comprises obtaining maximum absorption of the beam at predetermined workpiece thickness, in which inclination angle of cutting front is changed by adjusting beam geometry using beam formation
 
: Beyer, E.; Mahrle, A.

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Frontpage ()

DE 102008025043 A1: 20080520
DE 102008053397 A: 20081016
B23K0026
German
Patent, Electronic Publication
Fraunhofer IWS ()

Abstract
(A1) Die Erfindung betrifft ein Verfahren zum Schmelzschneiden von Werkstuecken mit Laserstrahlung. Es sollen dabei der Wirkungsgrad und der Absorptionsgrad gegenueber den bekannten Verfahren erhoeht werden. Bei dem erfindungsgemaessen Verfahren wird bei vorgegebener Werkstueckdicke eine maximale Absorption der Laserstrahlung erreicht, indem der Neigungswinkel [phi]c der Schneidfront durch eine Anpassung der Geometrie eines Laserstrahls mittels Strahlformung und/oder eine der Vorschubbewegung ueberlagerte Bewegung des Brennpunktes des Laserstrahls veraendert wird.

 

DE 102008053397 A1 UPAB: 20091222 NOVELTY - The method comprises obtaining a maximum absorption of the laser beam at a predetermined workpiece thickness, in which an inclination angle ( phi c) of a cutting front by an adjustment of the geometry of the laser beam using beam formation and/or a movement of the focal points of the laser beam superimposed to the feed motion are changed, and superimposing an oscillating deflection of the laser beam to a uniform feed motion. The oscillating deflection is sinusoidally carried out in a feeding direction. The laser is a high-performance-, fiber-, disk-, carbon dioxide- or diode lasers. DETAILED DESCRIPTION - The method comprises obtaining a maximum absorption of the laser beam at a predetermined workpiece thickness, in which an inclination angle ( phi c) of a cutting front by an adjustment of the geometry of the laser beam using beam formation and/or a movement of the focal points of the laser beam superimposed to the feed motion are changed, and superimposing an oscillating deflection of the laser beam to an uniform feed motion. The oscillating deflection is sinusoidally carried out in a feeding direction. The laser is a high-performance-, fiber-, disk-, carbon dioxide- or diode lasers. The movement of the focal points is carried out, so that the inclination angle of the cutting front is permanently changed and an incident angle of the laser beam ( phi (IN)) is kept within an interval to Brewster-angle ( phi (Br)). A path traverses between the two deflection points during the oscillating deflection of the focal point and is greater than the average diameter of the cross-section of the laser beam in the focal point. The oscillating deflection is performed with a frequency of 10-1000 Hz, is considerably performed a saw tooth function and a triangular function in the feeding direction and is carried out in an elliptical and figure-of-eight shaped manner. The laser beam is used with a rectangular or elliptical laser beam cross-section. The laser beam cross-section and/or the oscillation direction are adapted to the feeding direction. A cutting nozzle is adapted to the respective laser beam cross-section and/or the oscillating deflection of the laser beam, is used with an aperture opening for the laser beam with the rectangular or elliptical cross-section, and is considerably rotatable to the respective feeding direction. USE - Method for fusion cutting of a workpiece with a laser beam for the thermal separation of metallic materials in a large metal thickness. ADVANTAGE - The method is capable of efficiently and rapidly fusion-cutting the workpiece with high absorption coefficient, high performance and less energy and power consumption.

: http://publica.fraunhofer.de/documents/N-118865.html