German Collaboration Improves Accuracy and Speed of Metal-cutting Lasers

Research collaborators from Fraunhofer Institute of Laser Technology (ILT), KOSTAL Kontakt Systeme GmbH, Amphos GmbH, and Pulsar Photonics GmbH have combined the precision and quality of helical drilling and the efficiency of multibeam processing to enhance the performance of sheet metal parts cutting. The merging of processes aims to establish a single process that meets the accuracy and speed requirements of industrial-level production.

A high-power beam source with an output power of 300 W and pulse energy of 3 mJ performs the cutting. High pulse energy is necessary to divide the beam — sometimes into as many as 20 additional beams. The system retains the benefits in precision of helical drilling, which in the research takes place with ultrashort pulse (USP) lasers. Fraunhofer ILT developed and patented that method of drilling, which is particularly well suited for drilling high-aspect-ratio microholes into steel, glass, and ceramic elements. The technique delivers a focus diameter of 25 μm, with a profile roughness parameter (Ra) at the borehole wall of less than 0.5 μm.

Though precise, the method on its own is deliberate and only attainable at low process speeds. The addition of Pulsar Photonics’ multibeam module and Amphos’ high-power beam source expedites the processing speed.

The partners involved in the ERDF-funded project ScanCut developed a laser-based method of helical cutting with a multibeam module, paving the way for new solutions that can be used as an alternative to punching. Courtesy of Fraunhofer ILT.

Achieving full automation inspired the research project, called “ScanCut: Laser cutting in the stamping process.”

“We implemented electrically adjustable mirror and optics mounts to enable automatic adjustment of the beam position,” said Jan Schnabel, a scientist in Fraunhofer ILT’s Micro and Nano Structuring group. “Once we have programmed a suitable software routine, adjustments to the helical drilling optics can be initiated at the touch of a button without any of our staff having to travel to the site.”

The work applies prominently to the automotive industry. Modern vehicles cannot function without plug connectors transmitting signals and controlling voltages from one component of the vehicle to another. Traditional stamping and bending processes sufficiently produce these connectors.

Kerf produced by helical cutting on a metal sheet. Courtesy of Fraunhofer ILT.

Yet as automotive technology is advancing, so too is the number of connector elements regularly found in vehicles. Plug connectors are becoming increasingly delicate, intricate, and complex. Manufacturing must adapt to effectively produce parts with multiple, independently sprung contact points in compact spaces.

Using advanced technology, they are the same parts ScanCut has produced and is continuing to refine. Redundant, multiple contact points allow even the smallest contact systems to provide the robust electrical designs upon which reliable signal transmission depends.

The European Regional Development Fund (ERDF) and the state of North Rhine-Westphalia funded the project. After three years, the collaborators wrapped up the project in February. The researchers have since planned a follow-up project to expand the research and manufacturing initiatives.