Frankfurt a. M., Germany / 11/13/2018 - 11/16/2018
For the Additive Manufacturing process Laser Powder Bed Fusion (LPBF), elevated temperatures can be used to reduce part distortion and enable the manufacturing of materials susceptible for cracking.
Present pre-heating concepts heat the baseplate, leading to decreasing temperatures in the process layer with increasing build height due to heat conduction losses. A direct process layer pre-heating is being developed, as part of the Research Campus Digital Photonic Production DPP. Key part of this concept is the integration of a Vertical Surface Emitting Laser (VCSEL) from Philips Photonics GmbH Aachen into a LPBF-laboratory set up from the Fraunhofer ILT.
In addition to presenting a model setup to introduce the process at formnext 2018, Fraunhofer ILT will also show parts manufactured with direct process layer pre-heating.
The Fraunhofer-Gesellschaft has created the lighthouse project futureAM to systematically and continuously develop the Additive Manufacturing (AM) of metallic components. For this purpose, six institutes – all with a wealth of experience in the field of Additive Manufacturing – have entered into a strategic project partnership pursuing two fundamental goals:
1. Establish a comprehensive cooperation platform for the highly integrated cooperation and use of the decentrally distributed resources of the Fraunhofer-Gesellschaft in the field of AM.
2. Create the technological prerequisites to increase scalability, productivity and quality of AM processes in a way relevant to praxis for the production of tailor-made metal components.
The focus project has set itself ambitious goals, e.g.:
novel software for automated AM component identification and optimization
a scalable LPBF plant concept increasing productivity (by a factor > 10)
a process and system technology for generating spatially resolved, customized multi-material properties
an autonomous manufacturing cell for the post-treatment of AM components
The cooperation platform has not only been created through intensive cooperation in and between the individual fields of activity, but in particular through the establishment of a "Virtual Lab". For this purpose, all partners will participate in developing technology demonstrators.
The Fraunhofer ILT is striving for the qualification of new material concepts for Additive Manufacturing (AM) by the usage of Laser Metal Deposition (LMD).
Current research topics are covering the processing of e.g. challenging intermetallic alloys like Mo-Si and V-Si as well as eutectic alloys of the Fe-Ti- and Ti-Al-system. In the process of Laser Metal Deposition, high cooling rates are present by default. The resulting grain-refinement in combination with the solidification morphology of eutectics leads to an increase in strength and ductility.
LMD is chosen for the alloy development of laser-based additive processes due to the low amount of required powder as well as the degree of freedom in regard to the chemical composition.
In many cases, users lack reliable tools for the realistic calculation of process times and component costs for the LPBF process. Available software or online platforms typically take into account component volume and theoretical remelt rates, but neglect important influencing factors such as system type, support structures, component orientation and process parameters. This leads to significant deviations between calculated and in reality attainable characteristic values.
At formnext 2018, the Fraunhofer ILT will present a software tool with which users can quickly and precisely calculate process times, quantities and component costs for their components manufactured using LPBF. The range of functions can be adapted to the user's requirements and the software is suitable for experienced users and beginners due to its simple design.
Laser Metal Deposition (LMD) with wire-shaped filler material is an alternative to LMD with powdered filler materials.
Indeed, the overspray, the catchment efficiency, the insufficient quality of the powder, or the contamination of the component and the LMD system are factors that make powder-based LMD inadecuate for some applications. A disadvantage of the state of-the-art wire processing heads, however, is the lateral feed, which makes direction-independent processing impossible.
Fraunhofer ILT has developed a light-weight and compact processing head for laser material deposition (LMD). Weighing five kilograms, the head enables 3D LMD independent of feed direction with a coaxial wire feed. This processing head is being used in various projects for the deposition of iron-, aluminum-, nickel- and titanium-based alloys.
Within the scope of the International Center for Turbomachinery Manufacturing (ICTM Aachen), process development has been carried out for the nickel- and titanium-based alloys, IN718 and TiAl6V4, which are relevant in turbomachinery applications.
The Fraunhofer ILT has further developed the "TwoCure" process into industrial-ready machine technology. Using resin-based 3D printing, plastic components can be produced in large quantities in an automated process without supporting structures.
The "TwoCure" process works in a similar way to stereolithography with photolithographic exposure, which causes liquid resins to harden in layers. Until now, support structures were unavoidable because the often filigree plastic structures were supported and had to be connected to a building platform. These supporting structures are no longer necessary.
The "TwoCure" process is not only supported by 3D printing without supports: It also enables the components to be positioned without being connected to the building platform. The user can set up 3D components directly in the installation space at any location.
11.15 AMable - Support for European SME's in the Uptake of Additive Manufacturing
Ulrich Thombansen, Fraunhofer ILT, Aachen (D)
15.00 VCSEL-Based Preheating for LPBF
Andreas Vogelpoth, Fraunhofer ILT, Aachen (D)