Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V.

Rheinisch-westfaelische Technische Hochschule Aachen

Rheinisch-Westfälisch-Technische Hochschule Aachen

Markus Niessen

Wolfgang Schulz

Dirk Petring

Frank Schneider

Jens Schuettler

George Vossen

Georg Vossen

Jens Schüttler

In a method and device for machining material, an unfocused beam of laser radiation is focused and directed at the material surface, creating an interface of laser radiation and material to be machined. The beam waist, which results from the focusing the laser radiation, is held in the region of the interface of laser radiation and material. The spacing of the beam waist from the upper or lower side of the interface in the axial direction corresponds at most to triple the value of the penetration depth of the interface into the material. The focusing is effected such that components of the laser radiation are made divergent not just in the propagation direction downstream of the beam waist but also in the beam waist itself and/or also in the propagation direction upstream of the beam waist.

Method for machining material using laser radiation and apparatus for carrying out the method

The application relates to a method for determining the cut quality of a laser cutting process, said quality being assessed on the basis of the formation of solidification ridges along the cut face and/or burr formation on the lower edge of the cut face. In said method, a virtual laser cutting machine in a simulation program can be virtually operated with a set of values P0 from a parameter space P.; In a step a), the parameter set P0 is entered in the virtual cutting machine (), then in step b), a cut is made in the virtual workpiece by calculating, from partial differential equations with initial and boundary values, the progression of the melt film thickness over time and the position of the melt front at the apex of the cutting front according to the depth of the cut and the time, and then in step c), the spatial distribution of the ridge amplitude on the cut face is specified by projecting the progression of the absorption front onto the cut face and/or a spatial distribution of the burr is calculated from the progression of the melt film thickness over time and the discharge speed on the lower edge of the cut face, and in step d), a virtual cut quality is provided () for further analysis.

Method for determining the cut quality of a laser cutting process using a simulation program

A method for material removal to a predetermined removal depth from a workpiece employs a laser beam consisting of one or more sub-beams, each of the latter having a defined beam axis. The axis of the laser beam or the individual axes of the sub-beams are guided along a removal line at a predetermined travelling speed and the laser beam has a predetermined spatial energy flow density that defines a Poynting vector S with a value If (x) and a direction s, the spatial energy flow density creating a removal face with an apex formed by the leading part of the removal face in the removal direction and the face, creating a removal edge.

Method for material removal and device for carrying out said method

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Niederzier, Germany

Markus Niessen