The photonic backbone of Additive Manufacturing

ZEISS In-process Monitoring identifies and classifies defects in the powder bed

Regardless of the pandemic, forecasts in the 3D printing market remain bright. The technology is an increasingly interesting area of application for lasers, scanning optics and imaging solutions.

Estimates about the volume of the global 3D printing market in 2020 vary greatly in some cases. In a recent study, Reports And Data claims it’s a good USD 17.5 billion. The analysts from Lux Research have come up with USD 12 billion, reflecting the level of the Wohlers Report, an established source in the industry, which estimates the current market volume at USD 12.8 billion. Meanwhile AMPOWER limited their market analysis to industrial 3D printing (Additive Manufacturing; AM)—and reached an appropriately lower converted value of USD 8 billion.

Despite all the differences, the analysts agree that the young industry finds itself in a period of meteoric growth. The total global revenue crested a billion dollars for the first time back in 2013. According to AMPOWER, the market volume has multiplied by a factor of eight since then, while other cited market studies estimate it’s a factor of 12 to 17. And the outlook remains bright. AMPOWER forecasts an annual growth rate of 20 percent until 2025, which would catapult the industrial AM market to a volume of nearly USD 20 billion. Lux Research expects an annual growth of 15 percent, which, due to the high starting value, would amount to USD 50 billion in sales in 2030. Reports And Data has a significantly more optimistic forecast: a growth rate of 21 percent a year, which would place the total market at over USD 79 billion by as early as 2028. The Wohlers Report also foresees a 20-percent growth rate for the coming years, albeit only until 2022. Then global revenue would be USD 17.7 billion. Provided the growth curve doesn’t flatten significantly, the total market could cross the USD 100 billion threshold as soon as the 2030s.

Growth driven by the diversity of user industries

One key driver of this growth is rapid internationalization, while another is fast-paced technological development. New additive processes are always pushing into the market, which leads to accelerated construction processes and an increasing choice of materials. At the same time, the number of user industries is also on the rise. Now automobile manufacturing, air and space travel, energy and chemical plant manufacturers, medical technology, the food industry and mechanical engineering are all using AM processes. Users also include manufacturers of agricultural and construction machinery. In addition to prototypes and tools, they use additive processes indirectly to produce molds for axle housings and wheel hubs. They are also increasingly producing complex vehicle components in the smallest quantities, for which they are making use of the design freedom of the process: In some cases, with a well-thought-out design, it is possible to merge assemblies from many individual parts in a sandwich construction into one component, which reduces both assembly costs and the effort involved in certification, quality assurance and storage. And because lasers in sandwich construction processes only expose metal powder where the component structure is intended, it is also possible to significantly reduce the component weight and integrate new functions into components. This can range from cooling channels or devices for optimizing the supply of lubricants. The more specific the machines and vehicles, the more interesting it becomes to no longer store replacement parts, but to print them out as needed using saved construction data. In Industry 4.0, this opens up the prospect of printing out sensor-monitored mechanical components in advance when they are nearing the end of their life and proactively assembling them when maintenance is due, before costly defects and machine failures occur.

The photonics backbone: First AM system with 12 1-kW lasers

In order to quickly rectify the previous weaknesses of technology—slow build-up rates, limited construction space and lacking productivity—the manufacturers of industrially used AM systems are upgrading. SLM Solutions recently presented the first system with 12 lasers, each one supplying 1 kilowatt (kW). The sophisticated division of the scanning areas ensures that the lasers do not get in each other’s way when exposing the coated metal powder within the 60x60x60 cm installation space. The developers have also realized a zoom function based on a dual-lens system, which allows the spot size of each of the 12 lasers to be variably adjusted in the focal plane. As a result, the 12-laser system constructs metal parts 20 times faster than comparable systems with one laser. In addition to SLM Solutions, Dutch company Additive Industries is also making use of multi-laser technology. Their latest system has ten 1-kW lasers that allow for exposure in a 60x60x100 cm-large installation space. Other providers are working with concepts that use up to four Yb fiber lasers per system to expose the metal powder, based on four direct f-theta lenses as well as four redirected high-speed scanners each.

However, photonics isn’t just the backbone of beam forming and guidance. Laser beam diagnostics and precise performance measurements based on photonics are contributing to the increasing industrial maturity of technology. For some background, even small changes in the beam and scanning parameters can result in significant losses in quality in the construction phase. For that reason, Coherent developed a compact measuring system together with Haas Laser Technologies that measures key process parameters in direct proximity to the last f-theta scanning lens. The aim is to be able to correct the laser process as necessary on the fly in order to minimize expensive, time-consuming wastage in Additive Manufacturing processes. To this end, a special thin-film sensor is used that’s able to measure even high laser powers directly within microseconds. ZEISS Industrial Quality Solutions and AM plant construction company EOS are pursuing a different method of optical quality assurance in their additive processes. They are driving an in-process monitoring for supervising the powder bed. That’s because for a stable and error-free manufacturing process, an evenly distributed powder bed is a must. ZEISS offers a measuring system that determines the exact height information of the distributed powder layer and sends this information to be precisely analyzed by a neural network. If it encounters irregularities, it can make adjustments directly in the process. This ensures that powder bed defects are not transferred to the component during exposure. Today, laser melting in EOS systems is already being monitored using optical tomography processes. This involves the use of the pco.edge sCMOS camera from Excelitas PCO GmbH.

All of this makes one thing clear: The young industry is well on its way to industrial maturity and the necessary increase in productivity for additive mass-production processes. It’s a journey that wouldn’t be possible without photonic processes—whether it’s multi-laser systems, complex scanning optics or sensor and imaging solutions for complete process monitoring. Photonics is one of the factors enabling the meteoric growth in the 3D printing market—and as a central technology supplier, it will participate in the success of this technology.