Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Sonja Kittel is active.

Publication


Featured researches published by Sonja Kittel.


Proceedings of SPIE | 2010

Welding with Brilliant Lasers: Prospects and Limitations

Sonja Kittel; Friedrich Dausinger

Now that high brightness laser sources featuring high output power are commercially available, extremely small focal diameters and high power densities permit laser welding with a high aspect ratio at low heat input. With regard to an increase in productivity this implies a deeper weld depth at a higher feed rate and hence at a shorter processing time. In this research, a modular optical system generates focal diameters from 195 μm down to 15 μm for the purpose of identifying the prospects and limitations of the application of high brightness beam sources in laser welding. Metallographical analysis and observation using a high speed camera give information about the weld seam geometry and weld pool dynamics. Thus, the influence of minimizing focal diameters on process stability is evaluated: From the correlation of longitudinal cross-sections and high speed camera observation, an interrelationship between spiking and keyhole breakdown results. In dependence of the particular spot size and the beam quality of the laser source a new processing range arises. These observations are traced back to theoretical beam properties and a fundamental thesis about the applicability of a high brightness laser is derived. Eventually it shows that a small beam diameter is most advantageous for micro application.


LAT 2010: International Conference on Lasers, Applications, and Technologies | 2010

Low distortion laser welding of cylindrical components

Sonja Kittel

Automotive components are for the most part cylindrical and thus the weld seams are of radial shape. Radial weld seams are usually produced by starting at a point on the components surface rotating the component resulting in an overlap zone at the start/end of the weld. In this research, it is shown that the components distortion strongly depends on the overlap of weld start and end. A correlation between overlap zone and distortion is verified by an experimental study. In order to reduce distortion generated by the overlap zone a special optics is used which allows shaping the laser beam into a ring shape which is then focused on the cylindrical surface and produces a radial ring weld seam simultaneously by one laser pulse. In doing this, the overlap zone is eliminated and distortion can be reduced. Radial weld seams are applied on precision samples and distortion is measured after welding. The distortion of the precision samples is measured by a tactile measuring method and a comparison of the results of welding with the ring optics to reference welds is done.


Archive | 2007

Laser beam welding device and method

Klaus Spennemann; Sonja Kittel


Archive | 2007

Laser welding machine has optical system which produces annular laser beam comprising collimator, axicon, lens system and conical mirror

Sonja Kittel; Klaus Spennemann


Archive | 2010

WELDING METHOD INCLUDING WELDING AS A FUNCTION OF AN ASCERTAINED WELDING DISTORTION; WELDING DEVICE INCLUDING A DETECTION UNIT FOR DETECTING A MISALIGNMENT OF THE WORKPIECES; JOINED PART

Reiner Ramsayer; Axel Bormann; Marita Geisendoerfer-Pipp; Sonja Kittel


Archive | 2008

LASERSTRAHLSCHWEIßVORRICHTUNG UND LASERSTRAHLSCHWEIßVERFAHREN

Sonja Kittel; Reiner Ramsayer


Archive | 2007

Laser-beam welding device comprising an optical means for converting the laser beam into an annular laser beam and a corresponding laser-beam welding method

Klaus Spennemann; Sonja Kittel


Archive | 2010

Verfahren und Vorrichtung zum Bearbeiten und/oder Schweißen eines rotationssymmetrischen Werkstücks mit einem Laserstrahl

Markus Leimser; Thomas Ohmle; Joachim Radtke; Reiner Ramsayer; Sonja Kittel


Archive | 2010

Schweißverfahren, Schweißvorrichtung und Verbundteil

Reiner Ramsayer; Axel Bormann; Marita Geisendoerfer-Pipp; Sonja Kittel


Archive | 2009

Laser-beam welding device and a corresponding laser-beam welding method

Klaus Spennemann; Sonja Kittel

Collaboration


Dive into the Sonja Kittel's collaboration.

Researchain Logo
Decentralizing Knowledge