Fraunhofer ILT develops new laser beam-shaping platform for LPBF

Fraunhofer ILT develops new laser beam-shaping platform for LPBF


German analysis group Fraunhofer Institute for Laser Expertise ILT will showcase its new 3D printing beam shaping expertise at Formnext 2024.

Working with the Chair of Expertise of Optical Techniques (TOS) at RWTH Aachen College, the brand new platform, the Fraunhofer group is creating a check system for investigating advanced laser beam profiles. 

This platform can create custom-made beam profiles for laser powder mattress fusion (LPBF) 3D printing, enhancing half high quality, course of stability and productiveness, whereas minimizing materials waste. 

Fraunhofer ILT’s new system makes use of Liquid Crystal on Silicon – Spatial Gentle Modulators (LCoS-SLMs) to selectively bend the section entrance of the laser beam throughout 3D printing. It will probably reportedly obtain extra advanced profiles than the essential ring and rectangular shapes achieved in earlier analysis. This can enable researchers to research nearly any beam profile utilized in LPBF. The advanced profiles can then be matched with particular industrial 3D printing purposes to unlock optimum outcomes and tackle manufacturing calls for.  

“We are able to optimize the LPBF course of in a focused method,” defined Marvin Kippels, a PhD scholar within the Laser Powder Mattress Fusion Division at Fraunhofer ILT. He famous that the brand new platform will allow much less materials evaporation, cut back splatter formation, enhance soften pool dynamics, smoothen soften observe surfaces, and improve course of effectivity.     

The brand new LPBF beam-shaping system, at the moment below building, will probably be introduced for the primary time later this month at Formnext 2024, situated in Corridor 11.0, sales space D31.    

Marvin Kippels, a doctoral student in the Laser Powder Bed Fusion Department at Fraunhofer ILT. Photo via Fraunhofer ILT.Marvin Kippels, a doctoral student in the Laser Powder Bed Fusion Department at Fraunhofer ILT. Photo via Fraunhofer ILT.
Marvin Kippels, a doctoral scholar within the Laser Powder Mattress Fusion Division at Fraunhofer ILT. Photograph by way of Fraunhofer ILT.

What’s laser beam shaping?

Laser powers of 300 to 400 watts are utilized in many LPBF 3D printing processes. The usual Gaussian profile of those lasers presents challenges for industrial purposes the place high quality, effectivity and reliability are key.  

Philipp Kohlwes, the Head of L-PBF at Fraunhofer IAPT, beforehand informed 3D Printing Business that the excessive energy focus of Gaussian lasers creates uneven vitality distribution with an excessive amount of vitality within the center. This may trigger native overheating, undesirable materials evaporation, and course of instability, resulting in spatter and pores which harm half high quality. These points restrict the scalability of LPBF 3D printing, proscribing the utmost laser energy which can be utilized for many supplies. 

In response to Kippels, one technique to overcome that is by the usage of a number of lasers and optical programs in parallel. “Nevertheless, the prices scale not less than proportionally to the variety of programs put in,” he said. Moreover, these programs can’t at all times be used homogeneously, limiting their scalability for industrial purposes.  

To beat these challenges, Fraunhofer IAPT is investigating laser beam shaping to extend the productiveness of single lasers which can be utilized in multi-beam 3D printers. On this course of, the laser’s Gaussian profile is manipulated into completely different shapes earlier than sintering the steel powder. These shapes can facilitate even vitality distributions, translating to extra vitality within the soften pool. Kohlwes claims this homogeneity can enhance steel 3D printing productiveness by as much as 2.5 occasions, and enhance course of stability by 40%.

Earlier research have demonstrated that easy beam shapes like rings, rectangles, or a mixture of the 2 can improve half high quality and course of pace.  Nevertheless, the creation of extra advanced beam shapes stays largely unexplored as a result of limitations within the present expertise. 

Fraunhofer IAPT’s new platform reportedly overcomes these limitations, representing a brand new step for extra advanced shapes that may be custom-made to satisfy manufacturing wants.

The potential worth of this functionality was heralded by Kohlwes throughout final yr’s interview. “The higher the laser beam profile is matched to the respective software, the higher the vitality enter and the related course of stability,” he emphasised. Equally, Kippels defined that “There isn’t any one excellent beam form; each software has its personal necessities.”

Redistribution of the laser beam intensity during propagation after reflection at a phase mask of an LCoS-SLM. The initial distribution is on the left and the target distribution on the right. Image via Fraunhofer ILT.Redistribution of the laser beam intensity during propagation after reflection at a phase mask of an LCoS-SLM. The initial distribution is on the left and the target distribution on the right. Image via Fraunhofer ILT.
Redistribution of the laser beam depth throughout propagation after reflection at a section masks of an LCoS-SLM. The preliminary distribution is on the left and the goal distribution on the precise. Picture by way of Fraunhofer ILT.

Fraunhofer’s new LPBF beam-shaping platform 

The group’s new platform leverages LCoS-SLMs to unlock just about any laser beam profile for LPBF 3D printing. With a most laser energy of two kW, the check system can even assess beam shapes at excessive energy ranges, permitting the perfect profile to be matched for particular purposes.     

Fraunhofer ILT's new laser beam shaping platform. Photo via Fraunhofer ILT.Fraunhofer ILT's new laser beam shaping platform. Photo via Fraunhofer ILT.
Fraunhofer ILT’s new laser beam shaping platform. Photograph by way of Fraunhofer ILT.

In response to the Fraunhofer researchers, earlier research in beam shaping haven’t been based mostly on an in-depth understanding of the underlying course of mechanism. This has generally created ‘contradictory literature on the topic.’ 

Due to this fact, a extra elementary understanding of processes is required earlier than researchers can successfully decide laser traits, like soften observe geometry. To attain this, beam shapes should be optimized for particular purposes earlier than being adopted by producers. Fraunhofer IAPT’s new platform reportedly permits clients and venture companions to entry its flexibility for researching laser beam shaping to optimize LPBF 3D printing.      

“We’re nonetheless on the very starting, however we will already see the large potential that beam shaping can supply for the LPBF course of,” added Kippels. “Because of our versatile beam shaping, we will discover the perfect distribution for every course of, the perfect course of parameters for the duty in query.”

Novel laser beam profile created using Fraunhofer ILT's beam shaping platform. Image via Fraunhofer ILT.Novel laser beam profile created using Fraunhofer ILT's beam shaping platform. Image via Fraunhofer ILT.
Novel laser beam profile created utilizing Fraunhofer ILT’s beam shaping platform. Picture by way of Fraunhofer ILT.

Advancing laser beam shaping 3D printing 

Given its notable benefits for industrial steel 3D printing, beam shaping capabilities are being developed and commercialized by a number of gamers within the analysis and LPBF 3D printing spheres. Semiconductor and fiber laser specialist nLight is one such firm. It agreed to provide Munich-based 3D printer producer EOS with its AFX programmable beam-shaping lasers earlier this yr.  

The joint strategic cooperation made the lasers out there on EOS’s steel 3D printers, whereas additionally implementing different complementary laser-based applied sciences to reinforce their gentle engines for industrial purposes. nLight’s AFX laser expertise had beforehand been made out there on steel 3D printers from AMCM, an EOS Group firm.    

Elsewhere, Equispheres and Aconity3D used laser beam-shaping 3D printing to attain construct charges almost 9 occasions increased than business norms. Equispheres’ NExP-1 aluminum powder was used with Aconity3D’s AconityMIDI+ LPBF 3D printer to unlock speeds exceeding 430 cm3/hr for a single laser. 

The system was modified to make use of a PG YLR 3000/1000-AM laser with beam-shaping capabilities. By utilizing a formed beam over a zoomed Gaussian profile, the group lowered overheating and mitigated spatter formation throughout high-speed 3D printing. 

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Featured picture exhibits Fraunhofer ILT’s new laser beam-shaping platform. Photograph by way of Fraunhofer ILT.



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