“Perfect symbiosis of photonics and automation”

Axel Bauer: Automation plays a role in all areas of laser materials processing. Whether lasers are used to cut, weld, structure, polish or apply materials, they come into their own where they can be intelligently integrated into production processes. This is exactly what automation ensures. Linking light as a tool with intelligently controlled handling systems is essential here. The limits when it comes to productivity are usually set not by the laser but by the production machine. Again and again, we’re presented with the challenge of harnessing the full power and flexibility of the laser through automation. The same applies to additive manufacturing using laser powder bed fusion. When this process which was developed primarily at the ILT gained a foothold in toolmaking prototyping at the end of the 1990s, the unanimous opinion was that it was ideal for the construction of individual prototypes but was hardly suitable for series production. Over the past few years, however, we’ve realized that laser powder bed fusion is particularly suitable for producing complex components in small batches in aircraft, vehicles and mechanical engineering or medical technology. Intelligent process automation is crucial here. Increasing productivity and piece numbers requires further automation along the entire process chain. At the ILT, we develop innovative concepts for this, for example movable machining heads with local protective gas guidance which allow simple scaling of the installation space. Multi-beam source systems are used to further increase productivity. The market potential is also reflected in the fact that of the forty spin-offs of the Fraunhofer ILT, one tenth started out in 3D printing.

What’s important when it comes to automating laser processes?

Bauer: Controlling the processes! We can control coating processes online via a temperature regulation system. Welding processes can be controlled efficiently if access to the joining position, beam quality and process signals is available online. At the same time, AI aspects such as machine learning are increasingly playing a role in our research and development projects which take automation to an entirely new level. Machining different components with the same tool requires intelligent control strategies which record component-specific properties online and then incorporate this information into the production process. In combination with flexible handling technology, this allows extremely adaptable production lines which also allow a high degree of product diversity in series processes.

You’re describing a level of automation which is already very high. Is there still a need for research?

Bauer: Absolutely! The companies that the Fraunhofer ILT works for come from various sectors within the manufacturing industry: mechanical and plant engineering, aerospace, vehicles, electrical engineering and medical technology. Their quest for manufacturing that is as flexible, inexpensive and robust as possible is the driver for ongoing technological advances. Automation plays a key role here. Additive manufacturing is a good example. The combination of additive and subtractive processes promises high added value, as do approaches to combine laser structuring and polishing of metallic surfaces as part of highly automated processes. What previously required separate processes with different tools can now be done in a single setup with just one tool. There’s also a need for research into industrial ultra-short pulse laser (USP) processes. They’re used today to make microscopic holes in injection nozzles, to cut display screens for smartphones with no further machining or to structure print rollers. For the latter, the ILT has developed a multi-beam process with industrial partners which received the Science Award of the ‘Stifterverband für Verbundforschung’ in 2020. For such two-dimensional applications, a high degree of beam parallelization is necessary to make the technological potential of high-power USP lasers economically viable. The technology is still in its early stages. What we need to do now is to gradually optimize the individual control of hundreds of parallel laser beams and the online control of the processes in combination with highly automated system technology. Things get really complex in electronics and semiconductor technology. Here, lasers are integrated into fully automated process chains in order to machine increasingly miniaturized mass products with reproducible accuracy. With miniaturization, the degree of automation is increasing. And AI-supported systems will also gain in importance because the abundance of process and product data will only be manageable with intelligent, fast-learning software. The Fraunhofer ILT is active here too. We’re working closely with the RWTH Aachen and leading software manufacturers.

Electric mobility is beginning to take off. What role will highly automated laser processes play here—and is the ILT involved in the development?

Bauer: In battery and fuel cell production, lasers are used in a wide range of areas. We’ve therefore set up our own battery laboratory and hydrogen laboratory at the Fraunhofer ILT in order to try out and demonstrate all possible and promising laser processes. For the companies we work for, it's all about quality, reproducibility and process speed. In order to achieve the best possible results, we use our materials and process know-how to test different wavelengths for each material and adapt the beam shape in each case. In most cases, the processing machine rather than the laser is the limiting factor. So we also look at suitable process and system concepts and how they can be implemented from a software perspective. It is also important that battery manufacturers are able to fulfill their verification obligations in terms of operational safety. We can obtain useful indicators from the online process signals. When optimizing these processes, we rely on machine learning. When it comes to fuel cells, especially PEM (Polymer Electrolyte Membrane) cells, the challenge lies in scaling the production volumes. In order to help the technology achieve an economic breakthrough, process chains suitable for large-scale production with corresponding economies of scale are needed.

To integrate photonic processes into automated process chains, know-how from various disciplines has to come together. How does the ILT bring these various disciplines together?

Bauer: We’ll only be able to come up with effective and efficient automation solutions if materials science, production engineering, photonics and information technology work together. Collaboration between disciplines is therefore a central issue at our institute. Each discipline sheds light on the problem from its own perspective and with its own know-how. But as with a good orchestra, a conductor with a specific goal must produce a harmonious overall sound from the many different instruments. In our case, the project managers who pull all the strings and set the direction are responsible for this. This requires not only specialist competence but also a high level of methodological competence and communication skills, which we train in a targeted manner through advanced training measures. Experienced senior scientists are thus able to manage very large and complex projects with multi-million-euro budgets. For projects commissioned by industry, they often bring together an extremely wide range of skills. In addition to laser experts, specialists in simulation, sensor technology, automation and process engineering are involved in the development of online-controlled laser processes. The importance of collaboration between the various disciplines is also reflected in the Aachen campus: in the immediate vicinity of the Fraunhofer ILT, the Research Center Digital Photonic Production began operations in 2020. Under the leadership of the Chair of Laser Technology LLT, six faculties are working here on digitalization topics relating to photonic production. These range from materials research for 3D printing, the adaptive manufacturing of complex optical systems and ultra-high-precision machining to laser-based biotechnology and medical technology. Just next door, the Digital Photonic Production Industry Building offers opportunities for scientists and industry representatives to work together. Companies can establish themselves here to develop new components, systems, processes, process chains or business models in the field of optical technologies. In open space structures and shared laboratories, mixed teams from industry and science—from the ILT and LLT too—can interact. Photonics and automation often form a perfect symbiosis for further developing tomorrow’s production methods.

The combination of photonics and automation is also considered a driver of Industry 4.0. Will these two cross-sectional technologies become even closer in the future?

Bauer: We’ve been taking steps to automate production for decades now. The situation is similar with laser technology and photonic production. However, this ongoing development is now clearly gaining momentum. New sub-areas of digitalization such as cloud-based services, digital twins or even artificial intelligence are opening up interesting potential, especially for production technology. At the RWTH Aachen, a data center for controlling and monitoring industrial processes has been set up within the “Internet of Production” cluster of excellence. Around 200 scientists, some of them from the Fraunhofer ILT, were involved in this. It all began with a control system for numerous laser systems which our institute developed. It initially used the open source software Kubernetes in order to remotely install and control new laser systems within minutes. The RWTH Aachen excellence cluster focuses mainly on the digitalization of production technology. One aim is the real-time-capable, secure bundling of relevant data from various sources. 35 universities and other institutions as well as 50 firms and associations are involved. It’s all about the highly automated production of the future.

For the first time ever, Messe München is holding LASER World of PHOTONICS and automatica, its leading international trade fair for intelligent automation and robotics, at the same time in June 2023. What benefits will holding the two trade fairs together have?

Bauer: It promises numerous synergy effects for visitors, exhibitors and the accompanying technological forums. The advantages for visitors are obvious: short distances between the trade fairs and the opportunity to cover both aspects of photonic production—i.e. laser beam sources, components and processes—on the one hand and automation including the associated systems and software tools on the other. This will please production managers, specialists, strategists and development engineers from a wide range of sectors. In addition, exhibitors will likely endeavor to shed more light on the other view of things—i.e. automation in the case of a laser manufacturer—since they now have to reckon with a different group of visitors. This will provide opportunities to look at new topics at the company's own stand and will certainly attract more exhibitors from Germany and abroad to Munich. The large number of foreign exhibitors and visitors at both trade fairs will encourage this synergy effect. Last but not least, the fact that the two trade fairs will take place simultaneously will influence the topics of the specialist forums at both trade fairs and will also bring to light synergies in terms of content. This too will increase the appeal of the overall event and offer added value for visitors.

The Fraunhofer ILT is a regular exhibitor at LASER. What do you expect from being able to welcome automatica visitors too to your stand in the future?

Bauer: For us, the two trade fairs taking place at the same time should generate significant added value because we deal with the automation of photonic processes. Digital photonic production is nothing more than intelligently controlling a special form of light. If we can do this as quickly, flexibly and automatically as possible, our vision will become reality.