Scanning systems play a key role in networked laser processes

Within 30 years, SCANLAB has grown from a startup with a handful of employees into a global, medium-sized company with around 380 employees, which produces more than 35,000 scanning systems annually. In the interview, Georg Hofner, Spokesman of the Board of Management, looks back on his first LASER World of PHOTONICS in 1995, describes the technological development to high-performance galvanometer scanners and the use of diffractive optical elements – and talks about the potential of sensor-based quality monitoring of processes in additive manufacturing (AM) and remote laser welding.

Congratulations on your company’s 30th birthday, Mr. Hofner! How did SCANLAB start back then?

Georg Hofner: Unfortunately, we were unable to celebrate properly because of the coronavirus situation. But, in spite of that, thank you. Our beginnings in 1990 can be attributed to Hans Langer, managing director of the 3D printing specialist EOS. Before this, he was European Manager at General Scanning and wanted to adopt a course in the direction of 3D printing. When this didn’t find much favor, he established EOS. Parallel to this, he push-started the establishment of SCANLAB to develop scanner heads suitable for beam guidance in 3D printing systems. In the beginning, it was a small team focused on research and development. When I joined in 1995, we were hardly ten employees, a sub-tenant of EOS, and, for the first time, on a growth course. One of my first tasks was to plan a booth at LASER World of PHOTONICS, where we presented our inhouse-developed scanner heads to a broader audience for the first time.

This has now grown into a wide range of scanning solutions. Looking back, what were the most important milestones?

Hofner: Actually, over the years we have developed continuously, gradually opened up international markets, and gained a foothold in an increasing number of industries. Chance helped in some cases. For instance, our very important involvement in China started when we hired a graduate with a Chinese background. We hadn’t planned on deploying her there. But she took the initiative and acquired our first Chinese customers. From a technological aspect, our control platforms for scanner systems are milestones. We took the first step back in 1994 with the RTC 1000 control board. We are now in the seventh generation of these boards, which control high-speed scanning systems. With their current functions, they provide important bases for networked production in Industry 4.0. Other milestones included the change from analog to digital controllers in our scanner heads and the development of digital position detectors with which we achieved previously unattainable precision and resolutions in path measurement.

Current galvanometer scanners guide laser beams very quickly to their target with extreme precision and repeatability. What are the areas of application?

Hofner: There are many different applications. Naturally, we remain faithful to our beginnings in additive manufacturing. But they are also used in many different applications in laser marking and laser engraving, in microprocessing with ultrashort pulse lasers and in the production of displays and smart devices. Our sister company, Blackbird Robotics, integrates our scanner solutions into robot-supported remote laser welding systems. Medical engineering is also an important field, where, for example, our systems ensure precision in eye surgery. One thing all of these applications have in common is the high demand for speed and precision. Scanner systems guarantee this by using the massless tool light optimally. Instead of having to move lasers or workpieces, they guide the laser beam to the workpiece at high speed, using very light mirrors. The possibilities of digital control ensure increasing levels of precision and homogeneous energy input, which is important for a uniform font face in decorative markings and also for the quality of additively manufactured components, welding seams, and high-frequency microdrilling, such as for contacts in smart devices. Other uses include µm drilling for injection systems and now also increasingly applications in battery and fuel cell production. Users demand high repeatability, also minimum deviation in continuous operation, and maximum speed to guarantee high levels of productivity.

SCANLAB has a new sister company, HOLO/OR in Israel, that specializes in diffractive optical elements (DOE). What do you expect from DOE technology?

Hofner: On the one hand, the DOE market is interesting for our holding. On the other hand, we also plan to integrate this technology into our solutions – especially with regard to beam forming and beam splitting …

… is it conceivable that beam splitting could increase build speeds in additive manufacturing?

Hofner: It could certainly go in that direction. The possibility of duplicating or multiplying laser beams with the help of DOEs could be interesting for some AM applications. However, this would require an enormous amount of development work. In view of increasingly higher laser powers, it is also conceivable for other applications that the beam could be split in terms of parallelized processing to increase throughput in that way. In beam forming with DOEs, the aim is to adapt intensity profiles of the laser beam better and more precisely to suit the respective applications. In this area, we expect to have marketable solutions sooner than in the field of beam splitting.

Many of your target industries are developing digital networked, quality-monitored 4.0 processes. How could your scanner systems contribute to this?

Hofner: To control a laser process optimally, you can vary the laser power, the beam intensity on the component or the exposure time via the processing speed. In addition, the pulse speed of the laser and the scanning strategy must be attuned perfectly. All this is important, for example, to achieve clean curve and corner patterns. Without control, there would be a serious increase in thermal stress where the laser advances slowly. Our industry is currently working intensively to monitor the processes seamlessly with the aid of sensors – such as pyrometers, cameras, and OCT (optical coherence tomography) systems. For example, in the AM area we are working on direct interaction of our scanning systems with external sensors.

Are systems conceivable that integrate the sensor data into the scanner control in real time, thus enabling continuous readjustment of laser processes?

Hofner: This type of process control is certainly a target for the future. But currently it also helps users when we provide them with static or semi-static process data…

What does that mean?

Hofner: We know when the laser beam was at a certain position on the component and with what intensity. And with pyrometers, for example, we can measure the temperature at the same time. If an event occurs on the time axis that would suggest an error, with static systems, quality inspectors can afterwards look specifically at the area concerned based on the process data. Semi-static solutions allow the process to be adjusted directly when an event occurs. For example, in 3D printing, if there is an increased energy input in a powder layer, the problem could be rectified in the following pass by adjusting the parameters. The aim is to have highly dynamic systems that adjust the laser process continuously in real time – and, to do this, continuously analyze all incoming sensor data. The data technology and synchronization work required is enormous, but we are seriously looking at possible architectures for sensor-controlled real-time processes such as this. In networked systems like these, the scanner system plays a key role, as it has all the necessary information about the laser beam.

In which markets do you see growth potential for networked solutions such as these?

Hofner: Everywhere where laser processes are used in high-throughput production lines. Currently, this is the case with displays and smart devices, in the production of automobiles and batteries – and in the future, there may well be highly automated 3D printing factories. I think those are the most important target markets for quality-assured 4.0 processes.

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