Ceramics welded without furnace using ultrafast lasers

Researchers at the University of California San Diego have successfully welded ceramics together using an ultrafast laser, a process that usually requires the extreme temperatures of a furnace. The new technique, described in an

August issue of Science, works in ambient conditions and uses less than 50W of laser power. It enables the melting and fusing of ceramic materials without causing cracking, an issue often faced when welding ceramics with a furnace due to the extreme temperature gradients created. Ceramic materials are of great interest

to multiple industries because they are biocompatible, extremely hard and shatter resistant, making them ideal for biomedical implants and protective casings for electronics. However, current ceramic welding procedures are not conducive to making such devices. ‘Right now there is no way to encase or

seal electronic components inside ceramics because you would have to put the entire assembly in a furnace, which would end up burning the electronics,’ said Professor Javier Garay, of UC San Diego, who led the work in collaboration with UC Riverside professor Guillermo Aguilar. The researchers’ technique instead uses

an ultrafast laser to generate a series of ultrashort laser pulses, which are aimed along the interface between two ceramic parts so that heat builds up only at the interface and causes localised melting. The method has been named ‘ultrafast pulsed laser welding’. To make it work, the researchers had to

optimise two aspects: the laser parameters (exposure time, number of laser pulses, and

“Right now there is no way to encase electronics in have to put the entire assembly in a furnace”

duration of pulses) and the transparency of the ceramic material. With the right combination, the laser energy couples strongly to the ceramic, allowing welds to be made using low laser power (less than 50W) at room temperature. ‘The sweet spot of ultrafast pulses was two picoseconds at the high repetition

rate of 1MHz, along with a moderate total number of pulses,’ said Aguilar. ‘This maximised the melt diameter, minimised material ablation, and timed cooling just right for the best weld possible.’ As a proof of concept, the researchers

have welded a transparent cylindrical cap to the inside of a ceramic tube, with tests confirming that the welds are strong enough to hold vacuum. So far, the new technique has only been

used to weld small ceramic parts that are less than two centimetres in size. However, future plans involve optimising the method for larger scales, as well as for different types of materials and geometries.

Brose and IPG to develop in-line weld measurement technology for manufacturing automotive seat rails

Automotive supplier Brose has announced a collaborative project with fibre laser manufacturer IPG Photonics, in which the two firms will develop what they say will be the first direct weld measurement technology for the manufacture of automotive seat rails. The technology, known as In-line coherent

imaging (ICI), is able to track welding seams to detect surface irregularities and ensure weld quality. It will replace a current indirect measurement approach involving a one-hour validation process that halts production, enabling Brose to increase its manufacturing efficiency and minimise waste.

6 LASER SYSTEMS EUROPE AUTUMN 2019 The firm plans to

invest more than $6m in developing and implementing the technology by 2022. As part of the joint

project, Brose and IPG Photonics will study and analyse ICI-generated performance data including penetration measurements, surface irregularities, seam

tracking and the technical availability of the equipment. The project will help further inform manufacturing efficiencies, while also increasing the performance and consumer safety of Brose products. Brose initially plans

to pilot the welding technology in its facility

in London, Canada, then it intends to integrate weld cells into several of its manufacturing facilities in the US and Europe, with production set to begin early next year. In 2018 the firm produced more than 80 million seat rails globally, and expects to manufacture more than 105 million annually by 2024.


Garay et al

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