BEAM DELIVERY Scanlab’s IntelliScan series brings this


advantage to customers requiring scanners that don’t driſt. Teir encoder makes the scanner ideal not only for micromachining, but also for industrial 3D printing, where a laser beam has to deflect rapidly onto the workspace for jobs such as hardening powder into a desired shape. Tis technology is becoming increasingly favoured in micromachining because of high accuracy and throughput, but also for a growing market in 3D printing, which requires long-term stability. Scanlab’s head of product management,


The IntelliScan III 20 is ideally suited for a wide range of large-image field applications


company guides the client in choosing components such as beam expanders and shapers that alter the beam for particular applications. Traditional markets for polygon scanners have


included lithography and lidar mapping systems, as well as confocal microscopes that illuminate one spot at a time, rather than a whole field, thus requiring the illuminated spot to move quickly. But the need for faster scanning in material processing drives today’s market. Syncing ultrafast lasers with polygon scanners


can be challenging, as the polygon and the laser compete to serve as the master clock. Higher internal laser clock rates help this situation. ‘People are using polygon scanners with ultrafast lasers, but many more will benefit from polygon speed when they understand how to implement it,’ explained Helser. Real-time, active stabilisation devices, such as


those from MRC Systems that combine a fast closed loop controller with beam position detectors and piezo-driven mirror actuators, can also be necessary to minimise undesired beam fluctuations caused by vibrations, moving optics or thermal driſt. Tese devices are designed to give greater accuracy and more reliable beam delivery in precise laser processing.


Modern scanners for new applications Despite the advent of polygon scanning and ultrafast lasers, Germany-based Scanlab sees galvo scanners as their basic technology to meet current and future market needs, according to business development manager, Holger Schlueter. Modern digital optical encoder technology


allows galvo scanners to operate more accurately at higher speeds, by converting motion into digital pulses used for position measurements. An innovation by Scanlab lets them remove inertia-increasing components, improving dynamic performance for a galvo scanner that relies on this kind of feedback mechanism.


20 LASER SYSTEMS EUROPE ISSUE 33 • WINTER 2016


Michael Breit, is also optimistic about the future of their product: ‘Tere’s a huge trend toward higher throughput and increasing the field of view to print larger parts.’ Tis requires multiple scanners to operate together, and therefore an intelligent calibration procedure to match the scan fields perfectly. Tis will be key to bringing the technology into widespread industrial use. Still, system designs push the


New Jersey-based Tag Optics. Tat involves integrating a lens upstream of the scan head, to focus the beam as it moves across its target. Tag Optics develops custom lenses to meet the challenge of focusing the beam fast enough to keep pace with its X and Y movement. Using a speaker, the company’s computer-


trend toward higher throughput and increasing the field of view to print larger parts


There’s a huge


limits of scanner speeds, largely because of the high repetition rates of ultrafast, and power capabilities in areas such as micromachining. To increase speed, Scanlab uses a forward-looking servo algorithm called ScanAhead, implemented in the ExcelliScan scan head and RTC 6 control board. ‘We’re free of tracking error with this system; what you see is what you get,’ added Schlueter. Now, Scanlab is increasing its stake in the


polygon scanner market by acquiring Next Scan Technology. Tis Dutch/Belgian company has made a name for itself as manufacturer of the Line Scan Engine product family. Te two firms together create a team with complementary system approaches to ultrashort pulsed laser processing.


Focus on speed Galvo and polygon scanners position laser beams more accurately and faster than ever before. ‘Tese allow you to move a beam in X and Y space, but to deal with Z, you have to deal with focus,’ explained Craig Arnold, co-founder of


controlled adaptive optics system generates sound waves from 50kHz to more than 750kHz to induce density variations and therefore refractive index changes in a liquid, thereby changing the focus of the lens. Tat leads to a tuneable, liquid-based lens, whose focus can be changed on a sub-microsecond timescale. ‘Te main differentiating factors that our lens has over other liquid lenses or tuneable lenses is speed and optical quality,’ said co-founder Christian Teriault. And it’s no problem to integrate with an ultrafast-pulsed laser, as long as power density remains under 100W/cm2


. Tat makes Tag’s


adaptive lens suitable for marking, small-scale cutting, and welding, in markets that


include computer chips, silicon wafers, and glass etching. As lasers make their way into every


manufacturing application from fabric to car parts, technologies are limited by how fast the beam can move. Along with speed comes the need for accuracy: it’s difficult to ensure that the beam is positioned precisely in systems based on mechanical moving parts. Teriault points out that ‘you can’t break


Newton’s laws of physics. An object in motion keeps wanting to move: the faster something moves, the harder it is to stop at a precise location.’ With no mechanical parts, Tag’s lens makes sure that the laser will be focused continuously throughout the Z range.


Innovation driven by power and pulse rate Future industrial applications will require even higher scanning speeds than are currently available. Tese needs will drive innovation for yet higher power lasers with higher pulse rates. Current research looks for ways to synchronise


fast laser pulses with polygon mirrors in scanning systems. And specially designed coatings for optical components can play an important role in increasing power delivery. Perhaps most important, however, is visionary


Ultrafast laser with hollow-core fibre delivery


work to convince customers that new technologies are accessible. Speed, precision, and accessibility will all play important roles in future beam delivery systems.


@lasersystemsmag | www.lasersystemseurope.com


Scanlab


Amplitude Systèmes


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