2024 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2024): Poster Session
Program Organizers: Joseph Beaman, University of Texas at Austin
Tuesday 4:00 PM
August 13, 2024
Room: Salon JK
Location: Hilton Austin
Advanced Micro-fabrication for Radiative Property Characterization of Porous Packed Beds Using Two-photon Polymerization(TPP) Technique: Farhin Tabassum1; Rahul Ganpatrao Makade1; Shima Hajimirza1; 1Stevens Institute of Technology
In this study, we use an ultra-high-resolution micro-fabrication of porous media using two-photon polymerization (TPP) direct green laser writing maskless technology. By precisely controlling sub-nanosecond laser pulses and nonlinear laser-polymer interactions, TPP generates ultra-narrow, reproducible voxels, enabling sub-micron resolution by achieving feature sizes below the diffraction limit of light without the layer-by-layer limitations of traditional AM methods. We perform 3D printing using an inverted optical microscope (20X, 40X lens). We use various process parameters, i.e., refractive index of photoresist, printing speed, power, exposure times, tailored to achieve printing precision. Post-printing, we utilize a chemical bath composed of propane-2-ol:4-methylpentan-2-one for part developing and assess printing quality using a scanning electron microscope (SEM). We then measure the radiative properties, i.e., absorptance, transmittance, and reflectance, of the sample using spectroscopy within the wavelength range of 350nm – 750nm. Its high throughput fabrication and minimal material waste make it ideal for diverse engineering applications.
Design of an Electromagnetic Tool Changer for use in Ceramic Hybrid Additive Manufacture: Conor Farrell-John1; Robert Kay1; Matthew Shuttleworth1; Jaemin Lee1; Daniel Davie1; Louis Masters1; 1University of Leeds
Multi-material and hybrid methods have been proposed to improve the functional complexity of components fabricated using additive manufacturing. Hybrid ceramic AM integrates multiple processes such as paste extrusion, inter-layer drying and green machining into a single system, allowing for production of functional ceramics. Integration of these processes onto a print head reduces the build volume per axis stroke length, and working coordinate systems are used to avoid work piece collision. A tool changer mechanism has been developed that uses an electro-permanent magnet to collect and deposit the working tool. This is beneficial because the use of magnetism removes any moving parts that would be worn by ceramic particles. The electromagnet is ‘energise to release’, securing tools to the print head even in case of power failure. Incorporation of this device into AM processes creates new opportunities for multi-material and hybrid ceramic fabrication, such as LTCC embedded electronics for harsh environments.
Development of Powder Density Control L-PBF Methods for Tungsten Powder: Chiyen Kim1; Philip Morton2; Wicker Ryan3; Ho Lee4; 1Korea Polytechnics; 2P.M. Technologies LLC.; 3UTEP W.M.Keck center for 3D innovation; 4Kyungpook National University
Numerous studies and developments have been carried out on metal 3D printing technology with respect to the various metals. However, for refractory metals with high melting point materials, such as tungsten or molybdenum, there hasn't been much advancement in additive manufacturing technology. Even when the powder and base have been heated up, a major crack will still be created if the LPBF method is used because the refractory metal has a very high sintering temperature and there is an excessive temperature difference between the melting pool and the surrounding area. This study proposed methods for laser fusion of densified powder after compressing it to increase density, based on conventional powder metallurgy. Experiments were carried out on tungsten powder at various compression densities and pressures, gradually increasing to a green density. The results of the experiment will be presented and discussed at this conference.
Enhancing Standards Education in Additive Manufacturing and Robotics: A Systematic Approach and Curriculum Integration: Yue Zhang1; Haijun Gong1; Lianjun Wu1; 1Georgia Southern University
This project aims to develop students' consensus on the importance of standards and standardization through systematic training, including lectures, labs, seminars, and industrial experience. New course materials were developed and integrated into the curriculum of Manufacturing Engineering. Fundamental knowledge and specific standards from the American Society for Testing and Materials (ASTM) and the International Organization for Standardization (ISO) have been introduced to both undergraduate and graduate students. The study delves into the curriculum design and strategies for incorporating standards education into additive manufacturing and robotics courses. Faculty feedback indicated the ease of adoption of the course materials, with expressed interest in future adoption. Student surveys were conducted to assess the impact of the curriculum, revealing positive feedback regarding its effectiveness in educating students about standards and standardization.
Measurement Apparatus for Determining the Reflected, Absorbed, and Transmitted Energy during a Low Strain Rate Impact Event: Doug Meredith1; 1Los Alamos National Lab
Determining the energy absorption capabilities of lattice geometries during shock events is important for the development of impact-resilient structures for a variety of applications including bio-medical and consumer products. Current energy absorption measurement techniques for lattices are performed at constant quasi-static strain rates unrepresentative of real-world environments. A novel instrumentation package was designed and installed on a commercially available drop tower that uses first-principal conservation of energy techniques to determine the amount of energy absorbed in a lattice or solid coupon during an impact event to an unprecedented accuracy. The results provided by the apparatus can be used for Finite Element model validation, rapidly testing performance of additively manufactured materials, and for designing novel impact resilient structures.
Multi-Axis Wire-Arc Directed Energy Deposition of a Topology Optimized Aircraft Component: Isaac Rogers1; Matthew Stuart1; Shuzi Wang1; Kaley Faulks1; Jacob Fogg1; Arijana Reskusic1; Daniel Braley2; Henry Claesson1; Christopher Williams1; 1Virginia Tech; 2The Boeing Company
Wire Arc Directed Energy Deposition (Arc-DED) is being explored by aerospace manufacturers as an alternative to metal castings and forgings for the fabrication of large metal spare parts, as it does not require specialized tooling, reduces material waste, and significantly reduces production lead time. Its use also enables topology optimization (TO) in the redesign of conventionally manufactured components, which can further improve a part's structural efficiency and overall design-to-fly ratio. However, adapting TO results often requires design iteration to compensate for constraints inherent in the manufacturing process. The extension of Arc-DED to workcells that feature a coordinated robotic arm and tilt/turn table provide more toolpathing flexibility, such as allowing for part reorientation to produce overhangs not traditionally possible in 3-axis systems. In this work, a TO aerospace component is used to explore how part geometry and toolpathing decisions are affected when adapting TO results to multi-axis vs. 3-axis Arc-DED.
Performance Analysis of Selective Separation Shaping (SSS) Large-Scale Powder Bonding Technology: Xiang Gao1; Behrokh Khoshnevis2; 1Amazon; 2University of Southern California
Selective Separation Shaping (SSS) has demonstrated its efficacy in additive manufacturing (AM) across metal, polymer, and cementitious materials. Recent advancements in thick layer deposition have expanded SSS's applicability to the fabrication of large-scale products. Achieving high efficiency in SSS is crucial for large-scale cementitious part production. This study elucidates the integration of vibration and airflow to enhance powder deposition stability. Furthermore, it explores the relationship between deposition amount and nozzle movement speed. The optimized building speed of SSS is then presented and contrasted with existing commercial additive manufacturing technologies.
Physics-based Machine Learning for In-Situ Infrared Detection of Micropores in LPBF: Berkay Bostan1; Shawn Hinnebusch1; David Anderson1; Albert To1; 1University of Pittsburgh
The increasing benefits of machine learning (ML) are transforming the understanding, control, and mitigation of defects in manufacturing processes, particularly in Laser Powder Bed Fusion (LPBF). This study introduces an innovative ML framework that leverages physics-based in-situ infrared camera data to detect microscopic porosity in LPBF parts with high accuracy. Unlike previous approaches that focused on larger pores using simplified settings, our method excels in identifying smaller pores. When evaluated on previously unseen parts, the framework demonstrated over 90% accuracy while maintaining a false positive rate below 3%, effectively detecting pores more than ten times smaller than the sensor resolution. SHAP (SHapley Additive exPlanations) analysis was utilized to explore complex pore formation mechanisms under various conditions. This research demonstrates the crucial role of machine learning in advancing in-situ porosity detection and enhances our understanding of pore formation in LPBF processes.
Quantification of Recoating Forces in Binder Jetting: Raphael Burger1; Vincent Leube1; Moritz Nicklisch1; Daniel Günther1; 1Fraunhofer IGCV
Binder jetting in sand has recently become increasingly important for production in additive manufacturing. The performance of this process depends very much on the recoating speed. It is linked to the geometric accuracy of the components. If the recoating speed is too high, individual layers are displaced. The displacement of the component layers is not fully understood. Therefore, the recoating forces must be measured. In this work, the parameters "layer thickness", "recoating speed", "roller speed" and the influence of “printed layers” are measured. The values are between 7mN/cm and 40 mN/cm recoater length. Increasing layer thickness and roller speeds reduce the recoating forces. Increasing recoating speeds increase the recoating forces. Printed areas lead to measurable deviations in the force curves. To reduce the displacement of components, a reduction in the amount of sand used by the recoater is recommended.
Solar Harvesting and Photothermal Energy Generation via Multiple Transparent Plasmonic Fe3O4@Cu2-xS Thin Films: Anudeep Katepalli1; Yuxin Wang1; Anton Harfmann1; Mathias Bonmarin Bonmarin2; John Krupczak3; Donglu Shi1; 1University of Cincinnati; 2Zurich University of Applied Sciences; 3Hope College
We have developed a Photothermal Solar Tunnel Radiator for direct solar harvesting via transparent photothermal films containing plasmonic Fe3O4@Cu2-xS nanoparticles. The transparent substrates are arranged in parallel within a longitudinal tunnel enclosure. Captured sunlight is channeled through these substrates via a solar dome, where the photothermal coatings efficiently convert photons into heat, raising the substrate surface temperature. Acting as a utility thermal radiator, the heated substrates then dissipate thermal energy into the building space without requiring external power sources. At an ambient temperature of –10°C, the internal temperature of the PSTR photothermally rose to 40°C, demonstrating significant energy generation. This direct solar harvesting mechanism signifies a notable advancement in utilizing natural sunlight for energy-neutral systems with enhanced efficiency. We present the synthesis and characterization of Fe3O4@Cu2-xS nanoparticles alongside the analysis of photothermal thin films. We report the correlations between photothermal heating and the optical absorptions of these thin films.
A Fast Data-driven Residual Stress Prediction for Laser Powder Bed Fusion Additive Manufacturing Based on the Modified Inherent Strain Method: Praveen Vulimiri1; Shane Riley1; Florian Dugast1; Albert To1; 1University of Pittsburgh
Metal additive manufacturing processes, such as laser powder bed fusion or directed energy deposition, melt and fuse material to an existing structure to build a part sequentially. The repeated heating and cooling cycles introduce thermal stress, which can cause the part to distort and crack. While simulation can help predict the stress, the computational time required could potentially take longer than manufacturing the part. In this work, a data-driven, geometry agnostic mean-variance estimation model was developed to predict the residual stress in a few seconds. The model was trained on over 800 geometries from the Princeton University ModelNet database, simulated using the layerwise inherent strain method. For unseen parts, the normalized error of the predicted stress is around 10% on average, and 95% of errors are within two standard deviations of the predicted variance at each element.
Advanced Manufacturing of Structural Lithium-ion Batteries: Stephanie Guerrero1; Ana Martinez1; Ana Aranzola1; Eric MacDonald1; Alexis Maurel1; 1University of Texas at El Paso
Advancements in additive manufacturing have revolutionized the production of intricate designs, and the multifunctionality of the final item. For energy storage devices, it enables the development of shape-conformable lithium-ion batteries that also serve as a structural component. While most studies on the topic have been previously focused on addressing the compatibility of electrochemically-active material feedstocks with printers, this study rather explores a novel approach involving post-processing of 3D-printed structures manufactured via filament material extrusion and vat photopolymerization. The methodology entails designing and printing a 3D polymer substrate, followed by electrodeposition of a copper current collector and electrophoretic deposition of graphite-based electrode for its use as anode within a lithium-ion battery. This research unveils a promising method allowing battery multifunctionality: energy storage and load-bearing capabilities. Thanks to additive manufacturing, structural and shape-conformable batteries can be developed, thus enabling their seamless integration into limitless applications.
Advancing Manufacturing Efficiency: Electroplating Nickel onto 3D-Printed Polymer: George Thompson1; Mohammad Mahtabi1; 1University of Tennessee at Chattanooga
Traditional injection mold die plate manufacturing, involving time-consuming milling and hand polishing processes, takes over a month to achieve the necessary smooth surfaces. This research addresses the need for efficiency by exploring electroforming nickel onto 3D-printed, Stereolithography (SLA), materials, revealing a gap in cost-effective die plate production methods. This study aims to determine the feasibility of using electroformed nickel on 3D-printed die plates, investigating if it can provide a smooth, durable interior surface for injection molding suitable for thousands of operating cycles. Anticipated results include the development of a rapid and cost-effective method, utilizing electroformed nickel on 3D-printed surfaces to achieve smooth interiors, without the need for hand polishing, for injection molding. This process could revolutionize manufacturing efficiency, reducing production time from over a month to just a couple of days, and taking cost from tens of thousands to less than one thousand for most dies.
Challenges in Additive Manufacturing and Characterization of DLP for Optical Applications: James Garcia1; Michael Cullinan1; 1University of Texas at Austin
While additive manufacturing has been utilized for a wide range of applications, there are still boundaries from it being used in applications that require high resolution or low surface roughness. One of the applications that currently doesn’t utilize AM are optics as the surface requirements for a usable part are well beyond what can be done on commercial machines. While there are AM methods such as Two-Photon Polymerization that should be able to meet the requirements, the throughput by said method is much too low to be used in any large scale parts. Our work focuses on the utilization of Digital Light Processing (DLP) and understanding what are the limitations to layer thicknesses. By developing sub-micron layers and characterizing them, we can see how layer thickness varies, material properties vary due to amount of UV exposure, etc.Results will be discussed in an extended abstract.
Compression-twist Behavior of Additively Manufactured 3D Chiral Metamaterial: Minjung Ji1; Keun Park1; 1Seoul National University of Science and Technology
The 3D chiral structure, a type of mechanical metamaterial characterized by a negative Poisson's ratio, exhibits rotational behavior under axial loads. In this study, a novel 3D chiral structure composed of gammadion-shaped layers connected by inclined struts was designed, and its compression-twist capability was evaluated through finite element analysis. Compared to other 3D chiral structures, the gammadion chiral (GC) design features a torsion angle 1.75 times greater than the effective relative density and demonstrates a 17% improvement in torsion compliance. The study also found that altering the slenderness ratio, achieved by adjusting the number of layers in the axial direction, is more effective in enhancing performance than changing the height of the unit cell. Experimental validation of the GC structure was conducted using DLP printing technology to confirm its compression-torsion behavior. Furthermore, regression models were developed for the slenderness ratio and strut diameter using response surface analysis.
Confined Direct Two-phase Jet Impingement Cooling with Topology Optimized Surface Engineering and Phase Separation Using Additive Manufacturing: Harish Lattupalli1; Md Asif Iqbal1; Emily Cyr1; Sina Ghadi2; Scott Schiffres1; 1State University of New York, Binghamton; 2 State University of New York, Binghamton
This poster presents an innovative approach to address the growing energy challenge in data centers, focusing on cooling efficiency. Our project targets less than 5% of total energy consumption for cooling and aims to eliminate water usage by developing an energy-efficient two-phase cooling system. We introduce a unique two-phase wick structure with a thermal resistance below 0.01 K/W, designed to be directly printed on chips without the need for thermal interface materials, using a novel inter-material. To enhance cooling for high-power chips essential for AI, we've optimized the heatsink design through topology optimization. Our process development studies have fine-tuned wick porosity and microstructure, with validation through SEM, optical microscopy, and CT scans. An optimized manifold has been designed for uniform flow distribution using vat polymerization. Test artifacts were fabricated to set design parameters and evaluate coolant material compatibility.
Connecting Defect Formation to Manufacturing Parameters and Process Emissions in DED-Arc: Ariel Gluck1; Clayton Perbix1; Craig Brice1; Joy Gockel1; 1Colorado School of Mines
With emerging applications in wire-arc directed-energy deposition (DED-Arc) additive manufacturing (AM), understanding how material-specific microstructure and defects impact macro-scale properties is critical. Most DED-Arc defects can be categorized into porosity-type defects, characterized by voids, and residual stress-type defects, characterized by stresses that remain even after exterior loading has been removed. Residual stresses result from repetitive heating/cooling cycles as well as melt pool shrinkage during solidification, and contribute to part failure through cracking, plastic deformation, and distortion. The objective of this investigation is to understand formation mechanisms of common defects that occur during DED-Arc, establish a process window, and correlate sensor responses to expected defects throughout the processing space. Understanding how process parameters, particularly arc power, travel speed, and wire-feed rate, are related to process emissions for sensor detection can help regulate the formation of defects to produce optimized DED-Arc parts.
Design and Additive Manufacturing of Compliant Door-latch Mechanism Based on Reinforcement Learning: Yejun Choi1; Keun Park1; Yeonung Kim1; 1Seoul National University of Science and Technology
Recent advancements in additive manufacturing (AM) technology have spurred active research into mechanical metamaterials. In this study, we investigated a micro-lattice-based compliant mechanism capable of altering motion through interaction of the lattice structure constituting the mechanical metamaterial. Finite element analysis (FEA) was conducted on square and parallelogram-based lattice structures to examine their deformation characteristics. The design domain of the compliant mechanism employing the lattice structure, was subjected to FEA, and the analysis results were utilized for reinforcement learning (RL) for optimal design of the mechanism. The dueling deep Q-network (DQN) algorithm was implemented to enable efficient decision-making. Additionally, a reward function was suggested to design a compliant door latch mechanism capable of converting rotational motion into linear motion. The compliant mechanisms designed through the RL with auxiliary guidance of human experience were fabricated using fast-filament fabrication (FFF) type AM, and the relevant deformation behaviors were validated experimentally.
Determining Grain Size and Hardness in Laser Powder Bed Fusion Materials from Simulated Cooling Rates via Thermal Process Simulation: David Anderson1; Kevin Renteria2; Jorge Mireles2; Albert To1; Ryan Wicker2; 1University of Pittsburgh; 2University of Texas at El Paso
Achieving consistent microstructural properties of parts manufactured in laser powder bed fusion additive manufacturing processes remains a significant hurdle for process qualification in sensitive applications such as aerospace and nuclear industries. In this work, a means of predicting grain cell size and local microhardness based on part-scale simulations is presented. First, a stepped brick geometry is designed and utilized to evaluate microhardness and grain cell size at different degrees of residual heat accumulation, represented as a layerwise preheat temperature value. Then layerwise and local scanwise simulation models are built through a GPU-accelerated finite element method (FEM) based process simulation tool capable of efficient part-scale scanwise simulation. From these simulations, the local cooling rate near the melt pool is calculated, and a relationship with experimentally-determined microhardness and grain cell size is determined. The relationship is validated on an unseen geometry.
Development of an Open-source High-temperature FDM 3D Printer for High-performance Thermoplastic Materials: Charlotte Thompson1; Lillian Dejean1; Evan Garrison1; Santanu Kundu1; Matthew Priddy1; 1Mississippi State Univeristy
Various commercial systems print high-performance thermoplastics such as polyetherimide (PEI) and polyetheretherketone (PEEK) for medical implants, aerospace, automotive, and electrical components. Superior to common fused deposition modeling (FDM) materials, these polymers have advantageous chemical resistance, heat resistance, and mechanical properties. However, high temperature printing (e.g., chamber temperature of 150ºC) poses challenges in FDM. Most commercial systems for these materials are costly and lack modularity. This project aims to develop an open-source, modular, high-temperature, FDM 3D printer for high-performance thermoplastics that is easily constructed and user-friendly. It uses readily available materials, a Duet3D motherboard, and RepRap firmware for easy customization. The printer accommodates a 500ºC nozzle temperature, bed temperature of 250ºC, and chamber temperature of 200ºC. Its modularity allows for additional sensors to monitor printing parameters, including IR cameras for evaluation of thermal gradients. With open-source software, users can modify printing parameters to analyze their sensitivity on mechanical properties.
Digital Light Processing of Solid Polymer Electrolyte for Lithium-ion Batteries: Christian Fernandez1; Eva Schiaffino1; Eric MacDonald1; Laura Merrill2; Jorge Cardenas2; Ana Martinez1; Alexis Maurel1; 1University of Texas at El Paso; 2Sandia National Laboratories
Additive manufacturing enables the development of shape-conformable lithium-ion batteries with enhanced power performances. In this work, a custom LiClO4-based UV-photocurable resin is developed to serve, once printed, as a solid polymer electrolyte (SPE) component within lithium-ion batteries. SPE presents improved safety in comparison with traditional liquid electrolytes that use flammable solvents. The Digital Light Processing (DLP) vat photopolymerization process is employed to print complex geometries of the solid electrolyte component, demonstrating its design flexibility for its implementation into future battery architectures. The electrochemical and mechanical properties of various poly (ethylene glycol) diacrylate (PEGDA) polymer matrices with different molecular weights are analyzed and optimized. Linear sweep voltammetry, potentiostatic electrochemical impedance spectroscopy, galvanostatic cycling tests, as well as tensile strength tests are performed on the printed items. The need for a compromise between electrochemical and mechanical performances is also presented. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.
Effect of Laser Scanning Speed and Power on the Underlying Microstructure of SS316L Manufactured Using Laser Powder Bed Fusion: Saneej Samad1; Patrick Merighe1; Nadia Kouraytem1; 1Utah State Univeristy
Key process parameters in laser powder bed fusion (LPBF) play a crucial role in defining the metal’s meltpool and underlying microstructures. To support the transition from conventional manufacturing to LPBF, there is an innate need to understand the process-structure relationships in metals. In this research, the effect of laser scan speed and power on the meltpool morphology and the underlying microstructures of SS316L is evaluated. A constant volumetric energy density (VED) of 100 J/mm3 with constant hatch spacing and variable power and scan speeds is used to fabricate characterization coupons. The macro- and microstructure of SS316L is evaluated using optical microscopy (OM) for meltpool geometry and electron backscatter diffraction (EBSD) for grain analysis. Key microstructural fingerprints such as ASTM grain size, aspect ratio, grain orientation, and defects were revealed then compared to wrought SS316L. A constant correlation between VED and microstructure characteristics (e.g., grain size and aspect ratio) was observed.
Effect of Particle Morphology on Thixotropicity of SiC Colloidal Gel for Direct-Write Additive Manufacturing: Michael Odunosho1; 1Oklahoma State University
Robocasting is a promising tool for fabrication of multi-functional SiC due to its capability in tuning the properties of printed structures. Previous works mostly employed small SiC particle sizes (40nm – 0.7μm) during ink formulation process because of better dispersion and faster sintering rate. However, these small particle-sized SiC powders are expensive. On the other hand, large, irregularly-shaped SiC starting powders are low-cost but they can easily agglomerate and are therefore prone to nozzle clogging and difficulty in printing. In this experiment, the milling process is used to control the particle morphology. The powder is milled at different times (3, 7, and 10 hours) and the effect of milling time on rheology (thixotropicity) of the SiC paste is studied. Lastly, factorial design of experiment with Herschel-Bulkley model is used to study the effect of milling time on thixotropicity and printability of SiC paste via different nozzle sizes.
Effects of SiC Reinforced Particles on Melt Pool Dynamics and Porosity Formation in Directed Energy Deposition of SS 316L Metal Matrix Composites: Wenhao Zhang1; Yi Zhao1; Yue Zhou1; 1Embry-Riddle Aeronautical University
Understanding the heat and mass transfer mechanisms within a melt pool in additive manufacturing (AM) is of significance for process and performance control. In AM of metal matrix composites (MMCs), the underlying melt pool dynamics are challenging to be revealed due to different material properties and intricate physical interactions; however, the related investigations are still limited. This study introduces an advanced computational fluid dynamics (CFD) model designed to simulate melt pool dynamics and porosity formation in directed energy deposition (DED) additive manufacturing of SiC-reinforced stainless steel (SS) 316L materials. In particular, the effects of SiC content on melt pool oscillation and temperature as well as solidification are studied. In addition, the relationship between thermal variation and porosity formation in DED of MMC process is uncovered. Insights from this study help refine the process parameters, enhancing the performance of DED-built composite parts.
Elucidating the Role of Local Thermal Environment on Multi-track Melt Pool Morphology Variation for Inconel 718 Laser Powder Bed Fusion via CIFEM: Seth Strayer1; Alaaeldin Olleak1; Praveen Vulimiri1; Shawn Hinnebusch1; William Frieden Templeton2; Florian Dugast1; Sneha Narra2; Albert To1; 1University of Pittsburgh; 2Carnegie Mellon University
Despite advancements in finite element (FE) thermal simulation techniques for laser powder bed fusion (L-PBF), these models employ a functional heat source model, which invokes a tedious calibration process and provides inaccurate thermal fields compared to high-fidelity computational fluid dynamics (CFD) simulations. Consequently, the driving force behind multi-track melt pool size variation has remained enigmatic up to this point. In this work, the authors extend CIFEM to multi-track scenarios for Inconel 718 L-PBF to help address these issues. CIFEM's data-driven heat source model is trained to predict the thermal fields from multi-track CFD simulations with different cooling times to establish the role of the local thermal environment. By imposing these fields on the desired FE solution domain, the simulated melt pool sizes are within 10% error regarding experimental measurements up to five consecutive tracks while providing substantially more accurate thermal fields to traditional FE models.
Additive Manufacturing of Surface-based Structures for Studying Fluid Flow in Heat Sinks with High-Speed Imaging: Kyle Rathjen1; Madison Hedges1; Jay Teer1; Felicia Szleszinski1; Chad Westover1; Dhruv Bhate1; 1Arizona State University
In microelectronics packaging, efficient thermal management is important to ensure optimal performance and longevity of semiconductor devices. This work, conducted as an undergraduate class project, combines generative design and additive manufacturing to develop heat sink concepts to enhance thermal management of microelectronics packages, using fluid flow to enable chip cooling. While this work stops shy of thermal analysis, it demonstrates the feasibility of designing and manufacturing surface-based structures within the heat sink structure itself for optimizing fluid flow, thereby enhancing heat removal without needing bulky heat sinks.
Evaluation of Sources and Effects of Process Dynamics in Directed Energy Deposition: Emmanuel Bamido1; Michael Cullinan1; 1University of Texas at Austin
Directed Energy deposition(DED) is a metal additive manufacturing process used to build several structures used in the automobile, aerospace, and medical industries. The DED process involves multiple sources of process dynamics which influence the quality of the product such as variations in energy density, melt pool size, and powder catchment efficiency. Advanced modeling tools are, therefore, required to accurately model the process with the goal of increasing the quality of the products of DED. Previous research has utilized analytical, computational fluid dynamics models, and numerical modeling techniques. In this research, a multiphysics model has been developed to evaluate the sources and effects of the process dynamics on the final part produced. The effect of process parameters such as laser power and feed rate on the melt pool have been investigated. The model is useful due to the simplicity of the setup and its accuracy with respect to other models.
Feedforward Temperature Control in Laser Powder Bed Fusion to Reduce Build Failures and Achieve Consistent Microstructure: Shawn Hinnebusch1; William Templeton2; Praveen Vulimiri1; Alaa Olleak1; Florian Dugast1; Sneha Narra2; Albert To1; 1University of Pittsburgh; 2Carnegie Mellon University
Part qualification is crucial for advancing additive manufacturing, ensuring consistent microstructure and build quality. Excessive heat accumulation can cause significant distortion, recoater blade interference, irregular microstructure, and part discoloration, highlighting the need for precise temperature control. This study employs a thermal process simulation model to determine the additional cooling time required to remain below a specified temperature threshold. By leveraging a surrogate model, a true thickness layerwise model with powder is developed to determine the cooling time necessary for the part to cool below the specified temperature. Calibration and validation are conducted using an infrared (IR) camera to capture interpass temperatures. A recoater blade crash that occurred during the initial build is corrected with feedforward temperature control. The original build showed large hardness variation in high heat accumulation areas compared to other regions; in contrast, this variation is significantly reduced with the implementation of feedforward control.
Hybrid Directed Energy Deposition of Geometrically-Complex Pressure Vessels for Advanced HIP Canning and Digitally-Driven Powder Metallurgy: Jesus Cruz1; Mario Rodriguez-Parra1; Alexander Gomez1; Lauren Heinrich2; Thomas Feldhausen2; Eric MacDonald1; 1University of Texas at El Paso; 2Oak Ridge National Laboratory
Directed Energy Deposition (DED) is one of the highest production rate additive manufacturing processes; however, dimensional accuracies and surface finish are often reduced when compared to powder bed fusion. The ability to fabricate structures with internal cavities in DED is generally restricted unless the motion system enlists at least five axes, which are capable of maintaining the normal to gravity during deposition in order to create overhanging features to complete an internal cavity. A diversity of potential applications include pressure vessels and geometrically-complex hot isostatic pressing containers (HIP cans). The present work investigates the tool pathing to build a toroidal cylinder with an enclosed cavity. Leak testing and cross-sectional analysis were performed to demonstrate that the structure is sufficiently pressure tight with minimal porosity to be used as a complex HIP can - to enable the next generation of multi-material digitally-driven powder metallurgy.
In-Situ Powder Assessment by Frequency-Domain Thermal Response: Sina Ghadi1; Xiaobo Chen1; Nicholas Tomasello1; Srikanth Rangarajan1; Guangwen Zhou1; Scott Schiffres1; 1State University of New York
Metal powder defects in additive manufacturing can affect product quality. We present a non-destructive evaluation method sensitive to thermal properties at adjustable depths. By modulating the energy source and analyzing temperature responses in the frequency domain, we assess thermal properties and detect defects in metal powders and printed materials. Our setup identifies distinct thermal responses tied to material features like core detection, age, oxygen content, and particle size distribution. This method works with powder bed fusion lasers across materials such as Cu, AlSi10Mg, In718, SS316L, Ti64 G23, and G5. Frequency-domain measurements offer reduced noise compared to traditional methods. Utilizing machine learning, we identify core, age, oxidation, thickness, and size distribution, enhancing quality control and process monitoring.
Low-Cost Melt Pool Monitoring in Wire Arc Additive Manufacturing: Steven Wilmoth1; Bradley Jared1; Andrej Nycz2; William Carter2; 1UTK MABE; 2ORNL
The observation of melt pool process conditions in wire arc additive manufacturing (WAAM) is critical for process integrity. Current methods rely on expensive sensor technologies which limit accessibility and scalability and add difficulty in ensuring process reliability in a manufacturing environment. This ongoing study explores the efficacy of affordable sensor solutions in monitoring melt pool dynamics to solve these issues. By leveraging advancements in open-source sensor technology and low-cost wavelength and optical filters, the goal is to detect and eventually compensate for conditions such as overheating of the part and inconsistent melt pool size in the WAAM process. Such an approach holds promise for reducing costs and facilitating broader accessibility to WAAM techniques.
Machining PBF-L SMAs to Improve Geometrical Accuracy and Surface Quality: Shohom Bose-Bandyopadhyay1; Alan Burl1; Rodrigo Zapata Martinez2; Óscar Contreas Almengor3; Jon Molina Aldareguia3; Andrés Díaz Lantada2; Christopher Saldana1; Thomas Kurfess1; Kyle Saleeby1; 1Georgia Institute of Technology; 2Universidad Politécnica de Madrid; 3IMDEA Materials
Nickel-titanium (NiTi), a shape memory alloy, has high corrosion resistance, high strength, and high biocompatibility and is commonly used to manufacture biomedical stents. Albeit the same properties that make NiTi ideal for stents present difficulties to manufacturing using traditional techniques. To this extent, laser powder bed fusion (PBF-L) has quickly risen as an alternative to produce fine features. However, post-processing by electropolishing/etching is required due to geometric inconsistencies and surface defects inherent to the PBF-L process. During the post-processing steps material is non-preferentially removed from all surfaces, leading to deviation from the designed geometry. Contrarily, traditional machining can be used to achieve uniform material removal from select surfaces. In the present work, linear springs were printed using a PBF-L system and machined to final geometry using a computer numeric controlled (CNC) system. The springs were evaluated for geometric accuracy and shape memory properties.
Mixed Polymer Blend Composites Reinforced with Graphene Oxide for 3D Printing: Jackson Seiler1; Prudhvi Raj Pola1; Siddhesh Chaudhari1; Anuj Maheshwari1; Srikanthan Ramesh1; Frank Blum1; Ranji Vaidyanathan1; 1Oklahoma State University
Plastics are widely used in our everyday lives, but their impact on the environment is concerning. Efficient recycling must be exhibited without compromising the recycled material’s properties to mitigate environmental impact. Current recycling methods require the different types of plastic (#1 – 7) to be sorted to maintain uniform material properties. While recent strides have been taken to automate plastic waste sorting, this can be expensive.We are combining different types of plastic to create blends with decent material properties. This research examines the material properties of polymer blend combinations of recycled HDPE and PP with compatibilizers and graphene oxide. The extruded filaments are used in 3D printing to manufacture the specimens. Scanning Electron Microscopy (SEM) and tensile testing of 3D printed specimens are conducted to evaluate and compare the different blend combinations. The results indicate that the properties of blended polymers can be restored through compatibilizers and additives.
Multi-Axis Routing of Syringe Deposited Conductive Traces over Topology-Optimized Multi-functional Structures: Matthew Williams1; Ashish Jacob1; Guhaprasanna Manogharan1; 1Pennsylvania State University
Hybrid additive manufacturing can be troublesome when implementing process parameters using existing hardware which makes this research field increasingly prominent. Even after the integration of crucial hardware components necessary for Hybrid AM, there is no suitable software package capable of efficient toolpath planning of multi-material and multi-functional materials. Topology-optimized design would benefit from a planned process using hybrid manufacturing with simple electronics packaging design because of the need for optimized functional structures in the aerospace and automotive industries. The scope of this research takes multi-axis CNC toolpath strategies for syringe-deposited conductive inks over additively manufactured topology-optimized structures. A hybrid manufacturing machine utilizing multiple tools is used for the implementation of drone frame design with embedded signal and power transfer for electronic components. The resistivity and adhesion of multi-material structures are studied alongside existing manufacturing processes to show the validity of the new process using optical microscopy.
Real-Time Process Visualization in Thermoplastic Extrusion with Augmented Reality Monitoring: Jimena Morales Perez1; Eric MacDonald1; Mario Rodriguez1; 1University of Texas at El Paso
Thermoplastic Extrusion offers a balance of accessibility and design freedom for additive manufacturing (AM), enabling complex geometries with minimal material waste. Real time monitoring is often an essential task when parts are sophisticated with extended fabrication times, requiring complex path planning which is difficult for users to visualize. Given a camera position and GCODE for a specific layer, the live video feed can be updated with projected motion in the image to inform the user to understand the immediately following layers. This project has focused on developing an augmented reality (AR) overlaying the planned printing path onto the live video, based on (1) reading GCODE for specific layer and (2) priori knowledge of the location and viewing perspective of a camera, demonstrating the feasibility of integrating AR technology to enhance user awareness. This approach has the potential to improve user experience and monitoring capabilities in other highly specialized AM technologies.
Region of Interest Analysis for Top Layer Quality Control in Thermoplastic Extrusion in Additive Manufacturing: Daniel Banuelos1; Eric MacDonald1; Mario Rodriguez1; 1University of Texas at El Paso
Fused Filament Fabrication (FFF) provides a versatile, cost-effective solution for rapid prototyping of geometrically complex structures. Its ease of use and design freedom empower users to iterate quickly, experiment and create highly customized parts. Given a camera position, a layer number and the intended geometry (STL), a region of interest in the field of view of the camera can be generated to allow focused analysis for the top surface of the structure. The application of this software is to identify potential defects that are on the top surface of a given layer and can be assigned a z height associated with the given layer to potentially correlate with anomalies found in part characterization. By understanding the location of defects, computer vision process monitoring can be used to diagnosis problems during fabrication. This approach offers the potential to improve quality control and process monitoring in other highly specialized additive manufacturing technologies.
Ultrasonic Vibration Augmented Fused Deposition Modeling through Step-wise Contour Scanning: Raihan Quader1; Lokesh Karthik Narayanan1; 1North Dakota State University
FDM parts have low mechanical strength due to the voids from freeform deposition of polymers. We proved that applying ultrasonic vibration in between printing of layers can reduce voids and increase interlayer adhesion, resulting in better mechanical properties. This research presents an image processing algorithm to detect the contour of a part being printed and create toolpaths. From the detected coordinates, a step-wise contour scanning algorithm is developed to control positioning of a sonicator probe. An FDM printer is augmented with custom motorized rig to mount and move the sonicator probe in three dimensions through Raspberry Pi and Python programming. A custom g-code is used to pause and resume the printing of samples after predetermined layers are deposited. Layer-specific ultrasonic powers for inducing squeeze flow are determined through temperature monitoring by utilizing a thermal camera. Effect of this in-situ ultrasonic application technique on tensile properties is characterized.
Understanding Melt Pool Variation Due to Geometric Features and Scan Pathing: David Anderson1; Shawn Hinnebusch1; Haolin Zhang1; Praveen Vulimiri1; Alaaeldin Olleak1; Albert To1; Xiayun Zhao1; 1University of Pittsburgh
Melt pool variation in laser powder bed fusion printing processes is a potential source of porous defects that are inconsistent and difficult to model. To better understand the effects of laser scan pathing and local geometric features on residual heat and melt pool variation, simulations were conducted using PAMSIM (Pittsburgh Additive Manufacturing SIMulation), a GPU-based finite element method simulation tool and validated against in-situ monitoring data. From these simulations, a predeposition temperature is extracted based on the occurrence of a local minima in the thermal history of a given point prior to laser scanning. This metric for residual heat is correlated with changes in melt pool depth, which indicates transitions to and from a potential “keyhole” or overheating melt pool regime. From these results, a correlation between residual heat accumulation (due to local geometric features and scan vector length) and the corresponding melt pool geometry is presented.
Understanding Microstructure and Oxide Distribution in ODS Steels through Thermodynamic Simulations and Melt Pool Analysis in LPBF Processes: Sourabh Saptarshi1; Matthew deJong1; Iver Anderson2; Ralph Napolitano3; Christopher Rock1; Djamel Kaoumi1; Timothy Horn1; 1North Carolina State University; 2AMES Laboratory; 3Iowa State University
Laser powder bed fusion (LPBF) additive manufacturing (AM) offers a promising method for producing near net shaped oxide dispersion strengthened (ODS) steels, which are notable for their excellent high-temperature mechanical properties. Through thermodynamic simulations and melt pool analysis, the study aims to predict and examine the microstructure of 14YWT ODS Gas Atomization Reaction Synthesis (GARS) steels processed via LPBF. These analyses are vital for optimizing LPBF parameters and understanding the material's thermal behavior during rapid solidification and cooling which in turn affects the oxide growth and distribution. Thermal modeling plays a crucial role in this context, helping to predict and control the microstructure, particularly for down-facing surfaces that are susceptible to defects during fabrication. By adjusting process parameters like laser power, scanning speed, and layer thickness, the study aims to manage the temperature profiles during solidification effectively, ensuring uniform microstructure and tailored mechanical properties for high-temperature applications.
Unveiling Spot Melting Strategies for Microstructure Control in Electron Beam Powder Bed Fusion: Dang Toan Truong1; Haojun You1; Mohsen Taheri Andani1; 1Texas A&M University
Electron Beam Powder Bed Fusion (E-PBF) is an advanced additive manufacturing (AM) process that employs a high-energy electron beam to fuse metal powder into solid parts. Traditional line melting, while being employed in other laser-based AM methods, encounters challenges such as thermal constraints, limited microstructural control, and dimensional distortion. Leveraging the electron beam’s deflection speed of up to 4 km/s, spot melting in E-PBF is proposed as a solution, offering precise thermal profile control, improved microstructural control, elimination of lateral distortion, and less geometry dependency. This unique melting technique, coupled with an open-source programmable E-PBF system, opens a new regime in additive manufacturing that remains largely unexplored. Here, the authors successfully showed this potential by using different spot melting strategies to fabricate titanium Ti-6Al-4V alloy.
Exploring the Impact of Island Spot Scanning on Microstructural Texture in Ti-6Al-4V
Fabricated by Electron Beam Powder Bed Fusion: Haojun You1; Dang Toan Truong1; Mohsen Taheri Andani1; 1Texas A&M University
Electron Beam Powder Bed Fusion (EB-PBF) is a promising additive manufacturing technique for producing high-quality metal components. Recently, traditional scanning methods in EB-PBF, like linescan, Dehoff scan, and random spot scan, have been studied and lead to predictable microstructures. This study introduces a novel “island spot scanning” method to investigate its impact on the microstructural texture of Ti-6Al-4V (Ti-64) samples. The as-printed top surface, polished transverse, and polished longitudinal samples are characterized via SEM and EBSD. Significantly different microstructures are discovered, indicating a novel influence of the island scanning approach on the material properties.
Part Deformation Constrained Multi-load Support Optimization for Laser Powder Bed Fusion: Subodh Subedi1; Dan Thoma1; Krishnan Suresh1; 1University of Wisconsin-Madison
Support structures act as primary conduits for heat flow in laser powder bed fusion (LPBF). Frame supports have proven to be a good choice for LPBF, with no metal powder entrapment and ease of removal. We propose a framework for optimizing frame supports, subject to part deformation constraints. In a typical LPBF build process, supports evolve leading to time-varying thermal and structural loads. The proposed framework uses a multiload strategy to optimize support. Parts and supports are analyzed in tandem to compute the structural deformation at the end of each build layer. The optimal width of each support frame member is obtained through multi-load coupled optimization, subjected to constraints on the nodal deformation to avoid recoater collision and desired geometric accuracy. Numerical results demonstrate a reduction in part deformation when optimized supports are used.
Characterizing a Laser-Based Glass to Metal Sealing Process: Sebastian Brock1; Alyssa Watkins1; Brian Hlifka1; Edward Kinzel1; Robert Landers1; 1University of Notre Dame
Glass-to-metal seals are a critical component used in technologies that require electrical signals to be transmitted into or out of vacuum-tight or extreme-temperature environments. A typical glass to metal sealing process requires precisely formed metal and glass components, which must then be carefully bonded in a high temperature furnace. These processes require specialty tooling and are time consuming. In this project, we seek to create a quick, flexible glass-to-metal sealing technique by using a laser-based glass forming process. In our study, we identify four critical process parameters; namely, volume of inserted glass, speed of glass insertion, laser power, and heating time before glass insertion. We then create a set of seals with a broad set of process parameter values. Finally, to determine the most effective set of process parameters, we evaluate the manufactured seals for strength, stress distribution, and quality of glass-to-metal interface.
Thermal Emission-Based Geometric Mapping of Specular Glass Surfaces: Delaney Reynolds1; Edward Kinzel2; Robert Landers1; 1University of Notre Dame; 2Univ. of Notre Dame
Traditional line scanners used in 3D printing rely on diffuse reflection of light to determine form, and therefore it is difficult to produce accurate models of specular surfaces, such as glass. To overcome this challenge, geometry can be resolved by thermal emission. Using a mid-IR CO2 laser, morphology can be determined through emission detection via a thermal camera. To calibrate this method for accuracy, resolution can be tested with an optical flat, which is flat on the order of a nanometer. Changes in the height of the flat due to noise can be calculated by trigonometry from the angle of incidence of the laser and the movement of the flat with a motorized stage. After filtering, the surface of the flat displays approximately 60-micron resolution, with hope for future improvement.
Measurement and Control in Digital Glass Forming (DGF): Cindy Huang1; Balark Tiwari1; Nishan Khadka2; Timothy Welch1; Robert Landers1; Edward Kinzel3; 1University of Notre Dame; 2Unviersity of Notre Dame; 3Univ. of Notre Dame
Digital Glass Forming uses a fiber laser to heat a glass filament at its intersection with the workpiece, enabling deformation through thermal diffusion. This method allows the glass filament to wet the glass substrate and form continuous structures. However, increased laser power risks excessive temperatures, causing vaporization and bubble formation, limiting deposition rates. This research explores glass deposition in horizontal, vertical, and diagonal orientations using the fiber laser and feedback from thermal and machine vision cameras. The aim is to achieve precision, repeatability, and automation in the process. Additionally, the research addresses the "tailing" phenomenon, where the end of the glass structure becomes pointed. By partially reheating the glass tail and allowing it to reflow, the process aims to produce smooth ends without vaporizing the glass or damaging the structure. The strength of joints between glass structures will be evaluated through shear, cantilever, and 3-point bending tests.
Elucidating Microstructural Evolution Mechanisms in Tungsten via Layerwise Rolling in Additive Manufacturing: An Integrated Simulation and Experimental Approach: Sadman Durlov1; Aditya Krishna Ganesh Ram1; Hamidreza Hekmatjou1; Md Najmus Salehin1; Nora Ameri1; 1University of Texas at Arlington
In additive manufacturing, tungsten is recognized for its exceptional high-temperature resistance, making it suitable for extreme conditions. However, its brittleness and susceptibility to thermal cracking pose significant challenges. This study examines the microstructural evolution of tungsten processed through an innovative technique: rolling in laser powder bed fusion additive manufacturing. By combining advanced simulations with empirical research, we focus on understanding plastic deformation and microstructural transformations, particularly grain size dynamics, boundary evolution, and phase distribution. The integration of simulation and experimental data allows us to identify key mechanisms driving microstructural changes during the rolling process, enhancing our understanding of tungsten's behavior in additive manufacturing. These insights not only expand theoretical knowledge but also offer practical strategies for improving the mechanical properties of tungsten components. Our approach provides a robust framework for developing durable materials for challenging environments, optimizing additive manufacturing techniques, and broadening the application of tungsten in demanding sectors.