Mixing of the molten metal is critical, particularly in the case of bimetallic compounds, because brittle phases can result. For that reason, in addition to conventional laser welding, Manz also offers a welding process that almost completely stops the molten metal from mixing, resulting in very high-strength weld seams: laser welding in the overlap using high-frequency local modulation, or “wobbling.”
Using wobbling the depth and width of weld seams are configured in the micrometer range independently of each other. Results with a welding penetration depth that is constant down to a fraction of a millimeter can be achieved in continuous operation with high wobbling frequencies and high intensities in the laser focus. At the same time, material inclusions can be reduced.
A fully calibrated 3D scanner, camera technology and topographical measurements ensure high precision in all spatial directions during processing, paired with the speed and flexibility of remote operations. In order to absorb component tolerances or to enable processing on different operational levels, the processing heads also have an optical Z-axis. This allows highly precise positioning of the operational level of the scanner in the Z-direction in less than 10 ms.
Short-pulse laser welding
In addition to wobbling, Manz offers an additional welding process for bimetals which is based on high-frequency temporal modulation of the peak power of up to several hundred kHz.
Short-pulse laser welding allows even greater stability in controlling welding penetration depth. By the inherent nature of the process, it is possible to create any weld seam or weld spot geometries of any shape, from 50 µm wide micro-seams to weld spots of several millimeters in diameter. The very low levels of input energy and the highly efficient process design result in minimal thermal load, which plays a particularly crucial role in thermally sensitive components.
Nearly any combination of materials can be welded, including aluminum, copper, steel, Hilan, brass, stainless steel, etc. The extremely stable and precisely adjustable welding penetration depth also makes overlap welds possible with sub-materials of 300 µm thickness and less. The welding process is also very flexible with respect to surface quality. For example, highly reflective materials, such as chemically etched or polished copper, silver or gold, or extreme contaminations and oil and alkaline residues pose no problems whatsoever. The use of conventional laser welding processes would be impossible in these cases.
In addition to conventional laser welding, Manz also offers a welding process that almost completely stops the molten metal from mixing, resulting in very high-strength weld seams. Laser welding in the overlap using high-frequency local modulation, or “wobbling”.
Using wobbling the depth and width of weld seams are configured in the micrometer range independently of each other. Our automatic calibration method for a two-axis scanner system allows a wobble frequency up to 4 kHz in continuous operation with constant welding depth to micrometer accuracy while simultaneously reducing material inclusions.