Scientists from Heriot-Watt University in Edinburgh have welded glass and metal together using an ultrafast laser system, in what could be a significant breakthrough for the global manufacturing industry.
The scientists managed to successfully weld optical materials such as quartz, borosilicate glass and even sapphire to metals like aluminium, titanium and stainless steel using the Heriot-Watt laser system.
The system works by conducting very short, picosecond pulses of infrared light in tracks along the materials to fuse them together.
The new process could transform several sectors and have direct applications in industries such as construction, aerospace, defence, optical technology and healthcare.
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 – usually, the high temperatures and highly different thermal expansions would lead to the glass shattering.
“Being able to weld glass and metals together will be a huge step forward in manufacturing and design flexibility,” the Professor stated.
Often equipment and products that involve glass and metal are held together by adhesives, which can be messy to apply or result in parts gradually moving.
Outgassing is also an issue – organic chemicals from the adhesive can be gradually released and can lead to reduced product lifetime.
Professor Hand explained that the process relies on the incredibly short pulses from the laser.
“These pulses last only a few picoseconds, a picosecond to a second is like a second compared to 30,000 years,” he said.
“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, resembling a tiny ball of lightning, inside the material, surrounded by a highly-confined melt region.
“We tested the welds at -50C to 90C and the welds remained intact, so we know they are robust enough to cope with extreme conditions,” the Professor confirmed.