2023 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2023): Binder Jet AM: Material and Experiments
Program Organizers: Joseph Beaman, University of Texas at Austin
Tuesday 8:15 AM
August 15, 2023
Room: 417 AB
Location: Hilton Austin
Session Chair: Patryk Radyjowski, Advanced Cooling Technologies, Inc.
8:15 AM
Additive Manufacturing of Si-SiC Cermets by Binder Jetting with Si infiltration – Process and Material Properties: Patryk Radyjowski1; Saikamal Srinivas1; Chien-Hua Chen1; Benjamin Groth2; Luke Phalen2; 1Advanced Cooling Technologies, Inc.; 2ExOne
Siliconized Silicon Carbide (Si-SiC) is a promising material for high-temperature and high-wear applications. Additive Manufacturing (AM) of Si-SiC reduces lead times and opens the design space for complex geometries. The AM-generated SiC preform is densified using deformation-free pressure-less silicon metal infiltration. The binder jetting with high-ash binders is a high throughput, low heat AM method used for preform manufacturing. Subsequently, the binder is pyrolyzed and infiltrated by liquid silicon inside the vacuum furnace to achieve final properties. The manufacturing process is discussed, together with the investigation of minimal feature resolution capabilities. Furthermore, the mechanical strength of Si-SiC parts is studied in accordance with ASTM C1161 and including the statistical Weibull approach. Finally, a large-scale, high-temperature application of the described process is presented in manufacturing a 10in diameter by 10in tall Swiss-roll style combustor targeted at flare incineration.
8:35 AM
An Effective Method for Predicting the Mechanical Properties of Parts with Site-specific Microstructure: Li Sun1; Po-Ju Chiang1; Jonathan Jeevan Singham2; Wei Xin Tan1; John Samuel Dilip Jangam3; Chang Quan Lai4; 1HP-NTU Digital Manufacturing Corporate Lab, School of Mechanical and Aerospace Engineering, Nanyang Technological University; 2School of Material Science Engineering, Nanyang Technological University; 3HP Labs; 4School of Mechanical and Aerospace Engineering, Nanyang Technological University
Site-specific microstructures in metallic materials offer the potential to develop functional components with tailored properties. However, accurately predicting the mechanical properties of such materials is challenging. In this work, microstructure-based finite element simulation results reveal that, for materials containing randomly distributed identical phases, the mechanical properties are predominantly determined by phase proportion. Based on this finding, a method is proposed to predict the mechanical properties of site-specific material by developing a mathematical model that can predict the properties under varying phase proportions and then incorporating them as material data of the partitioned regions in a finite element model to predict its overall mechanical properties. The proposed method is verified by the experimental tensile test results of the site-specific pearlitic-ferritic steel fabricated using HP’s metal binder jet additive manufacturing technology. This method provides an effective way to predict mechanical properties and can facilitate the design of 3D printing site-specific alloy parts.
8:55 AM
An Experimentally-tuned Finite Element Model for Predicting Sintering Deformation in Binder-jet Additive Manufacturing: Roman Boychuk1; Mihaela Vlasea1; Kamyar Ghavam2; 1University of Waterloo Multi-Scale Additive Manufacturing Lab; 2University of Waterloo
Parts produced through binder jetting undergo shrinkage and distortion driven by densification and by the external forces of gravity and friction acting on the part in a softened state. This work presents an FEM-compatible deformation predictor based on the Skorohod Olevsky Viscous Sintering (SOVS) model to represent the solid-phase sintering process and predict the final shape of a complex sintered part. A sintering distortion artifact was designed, and sintered inside an optical dilatometer, where the part contour over time is recorded and used to train the sintering model through a regression algorithm. The model is then validated against variations of the training artifact, and other challenging overhang geometries under optical dilatometry, and yields a maximum contour deviation ranging from 3-7% after an initial round of optimization. This model presents a novel approach to predicting sintering shape deformation which uses experimental data with minimal material property knowledge.
9:15 AM
Binding and Alloying Properties of a Solid-free Organic Binder in Binder Jetting Additive Manufacturing of Steel: Wei Xin Tan1; Po-Ju Chiang1; Chang Quan Lai2; Adrian Ong1; John Samuel Dilip Jangam3; Ming Jen Tan1; Raju V. Ramanujan2; Li Ping Tan2; 1HP-NTU Digital Manufacturing Corporate Lab; 2Nanyang Technological University; 3HP Labs
In-situ alloying in steel can be achieved in binder jetting additive manufacturing technology by altering the composition of the liquid binder used. Carbon is often left as residue after high temperature sintering in organic binder. The diffusion of the carbon will result in the change of microstructure of the sintered steel part, often leading to enhancement in mechanical properties. Nanoparticles or suspensions are usually added to binder to achieve doping properties, but this can cause non-uniform particles dispersion and print nozzle clogging. Hence, we developed a solid-free binder with doping properties using an organic compound to act as binder and dopant simultaneously. In this study, the binding and doping properties were evaluated, and improvements in mechanical properties were observed in both the green and sintered parts. Finally, we also demonstrated the potential to fabricate site-specific alloy through the control of the carbon concentration using the newly developed binder.
9:35 AM
Elucidating Size and Location Effects on Green Density of Binder Jet Additive Manufactured Parts: Basil Paudel1; Albert To1; 1University of Pittsburgh
Despite large distortions inherent in Binder Jet Additive Manufacturing (BJAM), the geometric accuracy after compensation using continuum-based phenomenological models has been improved to 2-3% of the part dimension. Such prediction models, however, require the bulk green density of the part as an input parameter. The green density has been reported to depend on printing parameters including location within the build and may not be readily known. In the present work, we investigate this three-dimensional spatial effect on the bulk green density. The study is repeated for four directionally scaled samples to elucidate the role of geometric size as well. Results indicate that larger parts achieve higher bulk green density despite being in similar location within the build. At least a 5% variation in density is also obtained within a given ‘component-layer’ which can be attributed to the powder spreading and compaction process. A green density prediction model is proposed.
9:55 AM Break
10:25 AM
Equalization of Metal Powder for Binder Jet Printing: Michelle Niu1; Krzysztof Nauka1; 1HP Inc
Metal powders used in additive manufacturing often face the issue of variable powder surface characteristics, causing inconsistent part quality. As such, a “homogenization” treatment for metal powder surfaces may be advantageous for relevant fabrication processes. By using high-powered xenon flash lamp to rapidly heat powder samples, the surface energy of the powder can be brought to the same value regardless of the powder source and past usage. Pulse-heating the powder can cause the atomic structure of particle surfaces to undergo rearrangement, and adsorbed moieties can be removed. Effects of this treatment on metal powders have been investigated and evaluated by measuring the absorption time of water droplets on treated and untreated thin powder layers.
10:45 AM
Fiber-Reinforcement of Binder-Jetted Casting Molds for Multiple Usage: Jan Angenoorth1; Dominik Rumschöttel1; Florian Ettemeyer1; Bernhard Leitner1; Violetta Schumm1; Ismail Ünsal1; Daniel Günther1; 1Fraunhofer IGCV
Widely used sand casting with lost molds is an efficient and cost-effective way of producing geometrically complex components. As the demand for sand has tripled over the last two decades, finding new solutions for thermostable binder systems and ensuring the efficient use of resources is essential. To address this issue, the REINFORCED SAND project is exploring glass fiber-reinforced sand molds and temperature-stable inorganic binders within the binder-jetting process. The aim is to improve the mechanical properties of the 3D-printed casting molds to make multiple uses of these possible, reducing resource consumption and increasing profitability. For this purpose, various material systems and manufacturing parameters were examined. It has been demonstrated that fiber-reinforced sand molds can be used for multiple castings, and fibers can be principally processed in the binder jetting process. These efforts aim to make sand casting production more environmentally friendly and sustainable. The REINFORCED SAND project is a step towards achieving these goals.
11:05 AM
Microstructures, Mechanical and Thermal Property Evaluation of Binder Jet Printed High Conductivity Copper Parts.: John Samuel Dilip Jangam1; Thomas Anthony1; Jake Piderman1; Michelle Niu1; Elizabeth Galati1; Lihua Zhao1; 1HP Labs
Binder jet additive manufacturing technology involves binding metal powder particles together to produce a green part. In this work, HC Cu copper powder from Sandvik Osprey was used to 3D print green parts using proprietary organic and inorganic binders. Green parts possessed good green strength, typically around 4 to 8 MPa, after curing at 90°C or 120°C. Green parts were subjected to debind and sintering treatment to improve density and properties. Debound parts and parts sintered at different temperatures were subjected to microstructural examination to determine the effects of the binder on sintering. Fully sintered parts were subjected to HIP to achieve high density (~98%). Mechanical and thermal properties were evaluated in as-sintered and HIP conditions. Binder jet printed copper parts after HIP showed yield strength up to 80MPa, ultimate tensile strength 210MPa, elongation 55%, and thermal conductivity, typically 365W/m-K.
11:25 AM
Slurry-based Binder Jetting of Ceramic Casting Cores: Patricia Erhard1; Wolfram Volk1; Daniel Günther1; 1Fraunhofer IGCV
The production of complex sand cores to represent internal contours in castings is typically achieved by powder-based binder jetting. However, a trade-off between the load-bearing capacity during casting and the subsequent removability from the cast part leads to design limitations. Slurry-based binder jetting allows the processing of fine powders and the economical production of sinterable ceramic cores. Its performance, potential, and challenges are presented in the context of the foundry process chain. As drying affects material properties and process efficiency, detailed investigations are carried out to control the properties via drying. Average roughness depths of 1.2 µm and flexural strengths of 25 MPa were achieved using aqueous quartz slurry and appropriate process parameters. By incorporating predetermined breaking lines into the internal geometry of hollow casting core structures, the stress generated during the solidification of the cast metal induces decoring. A promising process chain is outlined for producing efficient, close-contour coolings in high-performance castings and digital code tags for part tracking in foundries.