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Distortion Effects in Deep Penetration Laser Micro Welding: Challenges and Results
P. Woizeschke and F. Vollertsen

Macro effects can probably not be simply transferred to the micro range proportionally to sheet thickness because of possible influences of size and scaling effects. In order to investigate distortion effects in the micro range reproducible experimental conditions have to be realized. The capability of a developed welding set-up to maintain those conditions is shown. The set-up consists of a laser scanning head, a novel clamping device and deformation measuring systems. Due to low stiffness of thin metal foils, handling the specimen can influence its shape and properties significantly. Therefore, influences on the welding process are minimized by appropriate sample preparation, handling, and the use of an integrated non-contact deflectometry measuring system. The suitability of the set-up for deep penetration laser micro welding and investigation of distortion behaviour in the micro range is demonstrated. Influences of geometrical and process parameters on out-of-plane and in-plane distortion effects are reported.

Keywords: Laser welding, micro welding, foils, aluminium, distortion, buckling, shrinkage, deflectometry

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