Fast and robust laser welding of sheet metal

Die Laserschweißoptiken der LPH-O-Serie von Scansonic sind für verschiedenste Anwendungen geeignet. © Scansonic

At EuroBlech in Hanover, Scansonic demonstrated with the LPH-O product family how the targeted use of beam oscillation can significantly expand the range of applications, even for low-cost optics.

When it comes to laser welding, soldering, cutting, hardening or coating, Scansonic is a good address with its wide range of different optics. The company can draw on a wealth of components and technologies to provide the right optics for many applications, from simple to complex.

Scansonic’s modular Scapacs system is used for the LPH-O series. With additional integrated scanners, the spot weld can be moved on the component surface at a frequency of up to 700 Hz. The focus oscillates, for example, by a few millimeters in a circle or spiral along the weld seam while the guiding machine, usually a robot, moves the optics. This increases the width of the weld seam while using a comparatively small spot. This results in greater gap bridging with still low heat input and, in addition, a more robust process and an increase in the maximum process speed.

LPH-O are used, among other things, in the production of prismatic battery cells, very thin aluminum covers (about 1 mm) are welded to the aluminum housing of the battery. Tight seams and the highest possible welding speed are the focus of this application. With the very thin wall thicknesses, heat input is a critical parameter. With the LPH-O and oscillating laser steel, the welding speed could be increased by 30 percent. In addition, it was found that a much smoother seam surface was achieved. For this aluminum application, the optics were supplemented with a specially developed inert gas nozzle.

Depending on customer and application-specific requirements, additional functions can be added to the optics of the LPH-O series. For the welding of tailored welded blanks (TWB) for hot forming, for example, an LPH-O with telescopic arm for the use of filler wire and the autofocus function controlled by it is of interest. TWB blanks are formed after welding. Therefore, the highest demands are placed on the weld seam quality. This applies in particular to blanks for hot forming. The sheets are AlSi-coated and there is a risk of formation of intermetallic phases, which lead to cracks during deep drawing. For this reason, the welding areas are generally laser-deposited in advance.

With the LPH-O with filler wire, it is possible to specifically influence the process via oscillation and filler wire in such a way that no intermetallic phases are formed in critical areas, thus eliminating the need for laser decoating.
In addition to the inert gas nozzle, filler wire and autofocus, the LPH-O can also be equipped with a protective glass monitoring system. In addition, camera-based quality monitoring, “SCeye”, can be integrated with all Scansonic optics. Should seam tracking or image recognition also be required in addition to the above options, remote optics from the RLW or tactile optics from the ALO family would be selected.

Testing customized applications in the laser application center

For all its optics, Scansonic attaches great importance to ensuring that the optimum variant is available for every customer application. This customer-centric approach is made possible by the modular system with which Scansonic can offer its optics with the equipment required in each case. With ten fully equipped laser laboratories, the Laser Application Center in Berlin is one of the largest in the world. There, customer applications can be tested in detail in order to optimize the process parameters and select the right optics variant.