The Fraunhofer Institute for Laser Technology (Fraunhofer ILT; Aachen, Germany) has won a competition conducted by international standardization organization ASTM International (West Conshohocken, PA) and is now working on a project towards standardization of machine condition monitoring in laser beam powder-bed fusion (LB-PBF; an additive manufacturing method). Fraunhofer ILT is focusing on selecting and qualifying imaging sensor technology that can be used to specifically monitor the condition of LB-PBF systems, and will derive cost-reducing recommendations for end users from the data.
Through the development of a new funding mechanism, ASTM allowed all organizations globally to submit proposals for addressing additive manufacturing standardization gaps and receive support from ASTM. “Our outstanding expertise in LB-PBF is based on 25 years of development in additive manufacturing and today allows us to profitably combine expert knowledge with digital technologies,” explains Niklas Prätzsch, project manager in the Laser Powder Bed Fusion competence area at Fraunhofer ILT. “After the completion of the proposals evaluation by ASTM executive section on research and innovation (F42.90.05), we were selected as a new project partner.”
Monitoring LB-PBF systems plays a very important role in the entire process because the high-precision, wear-sensitive, and expensive optics of the corresponding systems place high demands on cleanliness. Very fine metal powder is used and the optical systems can become contaminated during processing; therefore, they must be regularly cleaned as a preventive measure. The increasing number of optical systems and the ever-higher laser powers used in LB-PBF have an aggravating effect: “The load, probability of failure, and maintenance effort of optical systems are increasing, while users still have to cope with maintenance guidelines based on little experience with previous system generations,” says Prätzsch.
Fraunhofer ILT will be working until the end of 2021 on developing guidelines to standardize and simplify the maintenance and servicing of LB-PBF systems. “Manufacturers' current maintenance guidelines are often still far too conservative. In contrast to long-established manufacturing technologies, there is no or only a comparatively small database available as a basis for making decisions whenever maintenance cycles need to be determined,” explains Prätzsch. For this reason, users replace components too early and increase operating costs because both unproductive downtimes and the consumption of spare parts increase.
Fraunhofer ILT is now focusing on selecting and qualifying imaging sensor technology for monitoring highly loaded optical systems of LB-PBF machines. In addition, it is deriving recommendations for end users of the technology. It aims to help end users independently assess the condition of optical systems and plan maintenance cycles by using improved information about the actual condition of the system. These cycles will then no longer be based on subjective perception or experience, but on real data. This means that maintenance is less likely to be carried out too early or too late, but rather closer to the right time. This should significantly reduce costs for the end user.
With the standardization, the Fraunhofer ILT engineers want to enable end users to easily and quickly generate their own database, making it easier for them to correctly classify and interpret the data. The goal is a standardized decision-making best practice that recommends to the end user when and how to conduct maintenance or calibration.
“We are providing end users with recommendations that simplify their use of cost-effective imaging sensor technology for condition monitoring of optical systems in LB-PBF systems. Based on the data, they can then make informed decisions about whether or not maintenance is necessary,” says Prätzsch.
