Additive Manufacturing

Fraunhofer Center HTL develops and produces components made of ceramics, metals, and metal-ceramic composites through 3D printing processes. Standard materials include aluminum oxide, zirconium oxide, silicon carbide, and steel. The technology field of additive manufacturing encompasses the development of new material systems, manufacturing processes and equipment, the production of prototypes and small series, as well as the quality management of additively manufactured components.

The development of new material systems involves the formulation and synthesis of feedstocks for 3D printing. The goal is to adjust the processing properties of the feedstocks for the specific 3D printing process so that high-quality components can be produced while also achieving the desired material properties requested by the customer. Examples include adjusting the flowability of powder blends or adapting the processing properties of slurries for additive manufacturing.

Quality Management

Quality management is crucial for the successful implementation of additive manufacturing in industrial production. The HTL develops methods for in-situ monitoring of each step of the 3D printing process. One focus of quality management is achieving homogeneous and defect-free microstructures in the green body. The HTL has powerful methods for evaluating the homogeneity of green bodies. Methods for monitoring and optimizing the thermal treatment processes after 3D printing are also available. In this context, the HTL develops user apps for simulating thermal treatment processes.

Production of Prototypes and Small Series

The HTL produces prototypes and small series on behalf of customers. Customer inquiries are first checked for feasibility. If requested by the customer, component designs are revised using modern topology optimization methods. Two complementary additive manufacturing methods are available for 3D printing of components: stereolithography and powder bed printing (publication: Additive Manufacturing of Ceramics). In addition, new additive manufacturing methods promising high material quality and productivity are being developed at the HTL.

Separation of Shaping and Thermal Treatment

The 3D printing processes used for ceramics, metals, and metal-ceramic composites at the HTL deliberately separate the thermal treatment from the shaping process. This avoids some of the known difficulties of other additive manufacturing processes, such as thermal stresses and distortion in selective laser melting. Additionally, this approach opens up additional possibilities for material synthesis. For example, the open-pore preforms produced by the 3D printing process can be subsequently infiltrated with melts. Moreover, separating shaping and heat treatment allows for a cost-effective parallelization of the time-consuming thermal treatment. The thermal treatment processes can be carried out in different oven atmospheres and optimized using the ThermoOptical Measurement Systems (TOM) available at the HTL. If necessary, functional surfaces of the 3D printed parts can be finished using a 5-axis machining center. Furthermore, the 3D printed components can be integrated into larger systems using special joining processes.

Service Offering:

  • Development of components according to customer requirements
  • FE-based design and CAD construction of components
  • Development of new ceramic, metallic, and hybrid material systems for additive manufacturing
  • Formulation, characterization, and optimization of feedstocks for 3D printing
  • Quality management in additive manufacturing processes
  • Manufacturing of prototypes and small series using 3D printing for ceramics, metals, or metal-ceramic composites
  • Debinding and sintering of 3D-printed components
  • Melt infiltration of porous, additively manufactured preforms
  • Component characterization (dimensional analysis, microstructure analysis, mechanical and non-destructive testing)
  • Optimization of heat treatment processes and development of apps for simulation
  • Development and construction of 3D printing systems and system components

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Binder Jetting

At Fraunhofer-Center HTL, components made of metal, ceramic, and metal-ceramic composites are additively manufactured using Binder Jetting with a M-Flex printer (ExOne). The parts are generated layer by layer by selectively printing a liquid binder material onto a powder bed.

 

Stereolithography

Fraunhofer Center HTL develops and manufactures prototypes and small series of technical ceramics and mineral materials using 3D printing with a CeraFab 7500 (Lithoz). This device produces the ceramic component layer by layer using a stereolithography-based process, also known as Layerwise Ceramic Manufacturing (LCM).

 

Quality Management

To establish additive manufacturing in industrial production, ensuring high and reproducible quality of printed components is essential. The quality is controlled by the homogeneous and defect-free microstructure, compliance with tight dimensional tolerances, and low surface roughness.

 

New Methods

At Fraunhofer Center HTL, new methods for additive manufacturing are being developed and existing ones are being improved. The goal of these developments is to expand the state of the art and subsequently qualify the processes for industrial component production.