Robust laserhybridsvetsning av tjockväggiga fordonskomponenter

Purpose and goal

Regarding the general project goals, comprehensive results and knowledge was generated. The process stability was investigated and a new systematic measurement method was accomplished. Owing to the successful results, the demonstrator can become a pioneer laser hybrid welding application in Sweden. RobuHyb is continued by the new EU-FP7-project HYBRO. Some reprioritization put the fatigue tests outside the RobuHyb timeframe. Based on the results, four journal papers (not all yet published) and four conference papers have been created and presented.

Results and expected effects

The robustness of the process was investigated (especially undercuts and bead height), creating a deeper understanding of the process. The new CMT (Cold Metal Transfer) arc mode was compared with other arc modes and is deemed to work very well in laser arc hybrid welding of thick vehicle components. The newly developed measurement method satisfies diagnosis on beamer and process stability satisfactorily. Production environment and future implementation has been investigated, as a preparation for future production.

Approach and implementation

It was early decided to change the demonstrator from the rear axle bridge to the torsionally rigid cross member. Many experiments were made and analyzed thoroughly. Eight beamers where welded by LTU in a fixture made by Ferruform. Recently, eight additional beamers where tag welded by LTU and finally welded by Fronius (Austria, system manufacturer) to better compare results. Differences between three arc modes where investigated (CMT, Pulsed, Standard), in function and stability. Using laser hybrid welding with CMT, the tolerance window for the current joint types was mapped.