Welding breakthrough could transform manufacturing

Scientists from Scotland’s Heriot-Watt University have welded glass and metal together using an ultrafast laser system, in a breakthrough for the manufacturing industry. Various optical materials such as borosilicate glass, quartz and sapphire were all successfully welded to metals like aluminium, titanium and stainless steel using the Heriot-Watt laser system, which provides short, picosecond pulses of infrared light in tracks along the materials to fuse them together.

The process could transform the manufacturing sector and have direct applications in the aerospace, defence, optical technology and healthcare fields.

Professor Duncan Hand, Director of the five university EPSRC Centre for Innovative Manufacturing in Laser-based Production Processes based at Heriot-Watt, said: “Traditionally it has been very difficult to weld together dissimilar materials like glass and metal due to their different thermal properties - the high temperatures and highly different thermal expansions involved cause the glass to shatter. Being able to weld glass and metals together will be a huge step forward in manufacturing and design flexibility.”

Professor Hand explained that the process relies on incredibly short pulses from the laser. “The parts to be welded are placed in close contact and the laser is focused through the optical material to provide a very small and highly intense spot at the interface between the two materials - we achieved megawatt peak power over an area just a few microns across. This creates a microplasma, like a tiny ball of lightning, inside the material, surrounded by a highly confined melt region. We tested the welds at -50oC to 90oC and the welds remained intact, so we know they are robust enough to cope with extreme conditions.”