Keyhole welding

Smooth and clean welding seams - high stability in rough environments - extremely calm molten pool

The process

With keyhole welding, the material is processed with very high beam intensities. Different to heat conduction welding, a metal vapor is here created in addition to the metal melt that partially displaces the melt and leads to the creation of a vapor capillary (keyhole). The method is characterized by high process speed. The heat-affected zone is always limited, and so the material distortion is accordingly low. What remains is a narrow, evenly structured welding seam with a depth gauge that is often bigger than its width.

The process advantages of the diode laser

A big plus of Laserline's diode lasers is the calm molten pool that minimizes the amount of metal splashes on the workpiece and laser optic, leading to smoother and cleaner welding seams. With a protection class of IP54, the lasers guarantee (even without the protecting enclosures) process stability in tough application environments. Their high electrical efficiency of up to 50 percent and robust technology make Laserline’s systems a reliable and very economical tool for keyhole welding. Designed to last more than 30,000 operation hours, they are also very durable with low maintenance effort to boot.

Welding tailored blanks

With laser-based tailored blanks welding, several sub sheets shaped blanks are put together that will be transformed to car body parts later on. However, the process is often afflicted with inefficient and easily soiled lasers that furthermore leave unpleasant metal splashes on the sheet and welding optic. Laserline's diode lasers generate an extremely calm molten pool that hardly creates any splash. They also resist dust and moisture-intensive process environments.

ArcelorMittal Tailored Blanks has been using CO2 lasers for welding tailored blanks for more than 15 years now, and now replaces the old beam sources with modern Laserline’s LDF diode lasers which are clearly more economical.

Source: II-VI Highyag Lasertechnologie GmbH

Laser remote welding

To achieve quicker and more flexible process control when welding vehicle bodies or ships’ sides, laser remote welding is used more and more. Because the laser beam here is directed from a distance of over one meter onto the workpiece, the application requires a combination of high laser power and high beam quality. Laserline’s LDF diode lasers with beam converter offer the optimal system solution for this.

Application examples

Welding thick sheets with 50 kW laser power

Processes for welding sheets with thicknesses in the range of 10 mm to 25 mm are becoming increasingly popular for different industrial applications. For the laser-based process, seam preparation is currently a key challenge in this area. Variable gap dimensions are often unavoidable and must be bridged reliably and efficiently. With 50 kW laser power and spot sizes of up to 4 mm, Laserline also offers, with its LDF high-power diode lasers, a suitable solution for these applications. 

Aluminum welding

Aluminum facings that are mounted in a visible area require smooth and optically appealing welding seams. Here, Laserline's diode lasers achieve excellent results: the created joints are uniform in shape and require no rework. The always required filler wire out of aluminum silicon (ALSi), with which hot cracks can be avoided, may be applied during the welding process with Laserline's diode lasers in two ways: either over a tactile process optic or with the triple spot method using supplementary wire that was developed by Laserline. With this latter method, there are two side-spots (positioned in front of the main spot) which first ablate the coating at the edge of the wire melting zone. Because of this preparatory work, a controlled melting process is the end result without material transfer to adjacent areas.

In close collaboration with Audi and other plant suppliers, triennial process investigations were conducted and the requirements for diode lasers destined for aluminum welding were defined.