Product Code: ICAL08_609

Lbw of High Stiffness Light Weight Structures Generated by Scanned Fiber Laser Beams
Authors:
Renald Schedewy, Fraunhofer Institute Material and Beam Technology; Dresden Germany
Dirk Dittrich, Fraunhofer Institute Material and Beam Technology; Dresden Germany
Jens Standfu Fraunhofer Institute Material and Beam Technology; Dresden Germany
Berndt Brenner, Fraunhofer Institute Material and Beam Technology; Dresden Germany
Presented at ICALEO 2008

Stiff light weight structures can be generated by a spatial arrangement of thin metallic sheets stiffened by intersecting sheets. However welding of such slot-tab joints is more challenging than typical sheet metal welding as gaps are necessary in the interlocking regions to reduce insertion problems. A larger weld-pool has to be avoided to prevent that molten material drops out between the thin sheets. A very promising method to create the structure is to apply laser cutting as well as the combination of high beam quality fiber lasers with high speed laser scanners to weld the joints. Thus e.g. the parts can be precisely manufactured, the bridging of gaps can be enhanced, the weld interface width can be increased and the typically high welding speed reduces heat input. Several aspects of LBW for thin sheet metals are presented: LBW of a slot-tab joint made out of aluminium alloys (6xxx, 5xxx) process stability study and possible parameter fields. LBW of a slot-tab joint made out of galvanized steel process stability study and possible parameter fields. Mechanical tests - compares different joints - slot-tab joint, hidden T-joint, overlap joint . The weld quality is documented by metallographic examinations, hardness measurements and mechanical tests. High speed video sequences show weld pool dynamics and the stability of the welding process.