FEATURE: ULTRAFAST LASERS
This Lasea system uses two processing heads to direct two halves of a more powerful, single ultrafast pulse to the workpiece in order to increase processing throughput
be deflected through a single scanner to achieve higher throughputs, this option can result in a limited field of view and is not as easy to manage as using multiple scanners.
Bettering beam delivery It was also discussed at the UKP Workshop this year that in order take advantage of the increasing average power of ultrafast lasers, the most important developments that need to take place have to be carried out in the field of system technology. Ramos and Flemmer expanded on this by explaining that in the ultrafast regime, the laser sources have developed faster than the beam delivery technology used to wield them. Flemmer added that this is a good point, however, as the need for further system technology development is an excellent driver for innovation. The development of new beam delivery
used to wield the increasing average power of ultrafast sources to increase processing throughput. The other involves splitting the beam into multiple, lower-power beams using diffractive optical elements (DOEs) or beam splitting optics, which enables more surface area to be covered on a workpiece, or for multiple workpieces to be processed in parallel simultaneously. This approach has previously been used by Lasea when integrating 100W average power ultrafast lasers from Amplitude into its commercial laser machines. ‘Here, in order to make use of the higher power, we can split the beam in two, however in theory we can split it into four to improve the throughput of the machine even further. This would allow up to four parts (or a single part over a larger area) to be processed at the same time,’ explained Ramos. ‘At the SPIE Laser Beam Shaping Conference last year and the UKP Workshop hosted by the Fraunhofer ILT earlier this year, we presented the idea that, for typical ultrafast laser applications that can be performed well by the 10 to 20W average power lasers now widely available,
“We heard from an integrator recently that for most micromachining ultrafast
applications, 10-20W is enough”
these can be done more cheaply and faster using a 100W ultrafast source and four processing heads.’ Why stop at four beams though? Flemmer
shared that some of Scanlab’s customers are looking to split the beams of higher average power sources even further, and deliver them to between 10 and 20 scanners at one time to achieve parallel processing. ‘Most of the applications we are hearing about for this increased throughput and use of multiple scanners is in the electronics market, for example for cutting and ablation in the creation of PCBs or flat panel displays,’ he said. ‘This market is growing particularly well in Asia.’ He also explained that while multiple beams can
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solutions is therefore an important part of the many EU projects currently underway in which higher average power ultrafast sources are being developed. In addition to LAMpAS, Lasea is also
a partner of the projects ‘PoLaRoll’ and ‘HIPERDIAS’, both of which have required the development of new beam delivery solutions. Within PoLaRoll, for example, in order to cope with the higher pulse energy and repetition rate of the new femtosecond laser that has been produced, a new high- speed polygon scanner has also been developed. The resulting, high-throughput laser micromachining unit will replace the current masking method used in a continuous lithography etching process for micro-structuring stainless steel reels.
g
The microstructures of this metal surface were created using an ultrafast laser and provide self- cleaning properties
AUTUMN 2019 LASER SYSTEMS EUROPE 25
Lasea
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