2026 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2026): Control
Program Organizers: David Leigh, University of Texas at Austin
Tuesday 1:30 PM
August 4, 2026
Room: Zlotnick Ballroom 5
Location: AT&T Center
1:30 PM
Effect of Multi-Laser Beam Shaping on Spattering and Melt Pool Stability in Laser Powder Bed Fusion: Haoran Shi1; Wenda Tan1; Yash Parikh2; 1University of Michigan; 2EOS North America
Laser powder bed fusion (LPBF) commonly employs Gaussian lasers that concentrate energy near the beam center, producing steep thermal gradients, evaporation, and plume formation. These effects drive powder spattering and melt-pool instabilities, which contribute to porosity, surface roughness, and reduced process robustness. To resolve these challenges, this study will develop and evaluate beam-shaping strategies that redistribute energy away from peak intensities, reduce recoil-pressure-driven fluctuations, and promote more uniform thermal gradients. Specifically, multi-beam configurations (e.g., ring-shaped and offset beam profiles) and dynamic power balancing between beams will be explored to suppress keyhole oscillations, stabilize the melt pool geometry, and minimize spatter. These strategies will be assessed through combined experimental and modeling insights to identify operating regimes that enhance process stability and part quality. This work supports the broader development of adaptive beam-shaping approaches for more stable, controllable, and defect-resistant LPBF processing.
1:50 PM
Melt Pool Morphology-Driven Microstructures in Laser Powder Blown Directed Energy Deposition Via Variable Beam Shaping: Jack Dale1; Adriana Eres Castellanos2; James Zuback3; Carelyn Campbell3; Amy Clarke2; Samantha Webster1; 1Colorado School of Mines; 2Los Alamos National Laboratory; 3National Institutes of Standards and Technology
Laser powder blown directed energy deposition (DED-LB) is a disruptive additive manufacturing technology capable of building large volume metal parts at scale. Critical to part performance is microstructural development during deposition. The local solidification environment, moderated by laser characteristics, affects resultant microstructures. Variable beam shaping (VBS) mixes static beams shapes into a single output and has the potential to expand upon the benefits already seen with static shaping. A limited understanding of the technology’s effects on microstructure hampers wider application of variable shaping in DED-LB systems. The present work used nLight’s AFX-1200 laser to deposit single-tracks of Inconel 625 under seven variable shaping modes and two power levels. A transition between build-direction and scan-direction grain orientations is displayed. Coupled with solidification modelling, a laser modulated, melt pool morphology-driven mechanism is proposed. In industrially-relevant multilayer builds, this mechanism shows VBS to be a potentially efficacious method to control microstructures in DED-LB.
2:10 PM
In-Situ Qualification of Laser Power and Scan Speed via Melt Pool Emissions in Laser Powder Bed Fusion: Brian Johnstone1; Nicole Van Handel1; Patrick Merighe1; Maegan Lenertz1; Christopher Saldana1; Kyle Saleeby1; 1Georgia Institute of Technology
Determining optimal process parameters is critical for machine qualification in additive manufacturing. This process requires fabricating numerous parts with varying parameter combinations and ex-situ characterization methods, such as X-ray computed tomography and high-resolution microscopy, which can be time-consuming and costly. However, in-situ sensing technologies have become increasingly prevalent for part qualification and process monitoring. In this work, two qualification models—a convolutional neural network and a k-nearest neighbors model—were developed and compared for classifying melt conditions using photodiode signal metrics acquired during laser track formation in a metal laser powder bed fusion process. The models were trained using classifications derived from ex-situ micrographs and achieved accuracies exceeding 80%. Sensitivity analysis was conducted to identify the signal inputs with the greatest influence on model performance. The proposed models demonstrate the potential to streamline the qualification and requalification of additive manufacturing systems by reducing both cost and evaluation time while improving process efficiency.
2:30 PM
Working Curve Model to Enable Precise Curing of Functionally Graded Resin Systems: Supreet Thale1; Manas Vyas1; TaeYoon Oh1; Daniel Rau1; Michael Bartlett1; Christopher Williams1; 1Virginia Tech
Functionally graded materials enable spatial control of material properties within a single structure, but existing photopolymer-based additive manufacturing (AM) methods remain limited in their ability to achieve continuous, selective grading in both the XY-plane and Z-direction. In this work, a hybrid AM process that combines material extrusion chemical reaction bonding (MEX-CRB) and vat photopolymerization (VPP) is presented for high-resolution multi-material functional grading. A dual-component extruder deposits prescribed resin compositions as a pre-layer, while a bottom-up UV light engine system selectively cures the material with controlled exposure. To predict curing behavior across arbitrary resin mixtures, a working curve model is introduced that relates graded composition to depth of penetration and critical exposure. The model is validated using off-the-shelf resins with distinct optical and polymerization characteristics to establish a predictive framework for multi-material photopolymer FGM fabrication. The process application is validated through absorber gradients, stiffness gradients, and an octopus-inspired functionally-graded gripper.
2:50 PM
WAAM Development Cell with Adaptive Trajectory Control: Dylan Lewis1; Jared Bradley1; 1University of Tennessee
Using a custom three-axis motion platform and a Lincoln SP-140T manual MIG welder, an adaptive WAAM development cell has been realized. The system integrates a multi-axis platform with PLCOpen based controls using Beckhoff’s TwinCAT and a custom Raspberry Pi based Modbus controller to automatically operate the welder. Welder control is integrated into the PLC environment, allowing seamless integration between the MIG torch and the motion platform. The current hardware facilitates an adaptive framework whereby automatic torch height control and in-situ parameter adjustments can be implemented in real time to increase the control of the WAAM process during execution. Initial work has focused on trajectory control strategies to introduce an additional capability for real time path correction during the WAAM process. Current efforts have validated motion functions with integrated welder control for simple trajectories. Future plans are focused on developing a flexible solution with complex trajectories that include on-the-fly path compensation.
3:10 PM
Precision Density Control in Binder Jetted Composites via Selective Vacuum Infiltration: Max Gunn1; Owen Josephson1; Talmage Madsen1; Nathan Crane1; 1Brigham Young University
Binder jetting can produce high density single component parts, but it is not currently possible to design a process to hit a specific target density. Achieving targeted density is important for creating parts to simulate other materials for testing purposes. This talk presents a method for creating parts with precise density targets and moment of inertia by producing porous powder scaffolds and subsequently densifying them via selective vacuum infiltration. By precisely dosing an infiltrant into the green body, target densities are achieved without altering external geometry, overcoming the mass distribution limitations of traditional manufacturing. Preliminary results using a mullite-epoxy system demonstrated exceptional accuracy, achieving a mean density error of less than 0.7% in 10 mm cubes. The study investigates infiltration scalability and the development of gravity-induced density gradients in larger components.
3:30 PM
Angled Printing with Traditional 3-Axis Gantry: Alex Roschli; Liam White1; Tyler Smith1; Luke Petit2; Eric Black2; Jay Evanovich2; Brian Post1; 1ORNL; 2AES
Traditional extrusion 3D printing deposits material layer by layer on the XY plane with layer changes incrementing along the Z-axis. Angled printing is different in that the deposition plane is rotated about one or more of the three axes. This rotation of the printing plane enables geometries to be constructed without support material and enables production of large parts by taking advantage of the X and Y axes that are often longer than the Z axis on industrial machines. Printing on a rotated plane typically requires at least one additional motion axis to allow for rotation about the X- or Y-axis. Rotation axes can be expensive and add significant complexity. This paper will instead focus on fixed extruder modifications and adapted control and slicing systems to enable 45-degree printing on traditional gantry systems. These effective modifications have allowed successful printing of large tools that would have previously required multiple prints.
3:50 PM
Physical Validation of a Threat Field-Based Online Planner for Multi-Robot Additive Manufacturing: Julienne Cantu1; Ronnie Stone1; Zhenghui Sha1; 1University of Texas at Austin
Cooperative 3D printing (C3DP) is an advanced additive manufacturing framework in which multiple printing agents simultaneously fabricate large-scale parts, with collisions between agents being a major challenge. This work focuses on an online threat field-based method for generating minimum-risk homing trajectories as opposed to pre-determined toolpaths. The proposed algorithm directs printers toward regions of lower collision risk while accounting for physical constraints. As this methodology is limited to simulations, this paper focuses on physical validation through experimental characterization of printer response latency and pause-and-resume uncertainties affecting print quality. A Design-of-Experiment approach is used to evaluate the effects of dwell time, command frequency, pause duration, and filament retraction on response latency and print quality. Preliminary results indicate that latency and pause-related uncertainties significantly affect printer response consistency and print quality, highlighting the need for optimization of key operational parameters to improve the reliability of online collision avoidance in C3DP systems.