Session Sheet - 2026 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2026): Process Development, Modeling, Properties

2026 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2026): Process Development, Modeling, Properties
Program Organizers: David Leigh, University of Texas at Austin

Tuesday 8:00 AM
August 4, 2026
Room: Pecos
Location: AT&T Center

8:00 AM
Wire-Arc Additive Manufacturing Process Development for Martensitic Stainless Steels: Matthew Mikels¹; Mason Werner¹; Steven Williams¹; Jack Tunny¹; Bradley Jared¹; ¹University of Tennessee, Knoxville
    The corrosion resistance and high-strength properties of martensitic stainless steels have led to a focus on development for naval applications. Still, welding and wire-arc additive manufacturing (WAAM) can present unique challenges in processing these materials. A key challenge is determining appropriate processing parameters for WAAM. Finding a process window that can optimize geometry, part quality, and properties requires extensive development time and cost. The described work looks to use an analytical model and physical properties to create an a priori WAAM process window that can predict bead geometries and quality. Predicted qualitative and geometric results are compared to bead-on-plate tests to evaluate model validity. Experimental data for this work were acquired using both an in-situ multi-modal sensor array and an optical profilometer, after which, data analysis provides melt pool and bead geometry information for comparison against the model.

8:20 AM
Experimental Evaluation of Unsupported Overhang Limits in Steel Parts Fabricated by Wire-Based Directed Energy Deposition: Youssef K Hamidi¹; Josiah White¹; Caleb Cannon¹; Kazi Md Masum Billah¹; ¹University of Houston Clear Lake
    Wire-based directed energy deposition (DED) enables the fabrication of large-scale metal components with reduced material waste and increased design flexibility. However, unsupported overhang fabrication remains a significant challenge due to thermal instability, bead sagging, and insufficient interlayer support during deposition. This study experimentally investigates the support-free overhang capability of steel structures fabricated using a Meltio M450 system. Steel wall specimens with varying overhang angles were printed under constant processing conditions to determine the maximum printable unsupported geometry. The effects of overhang angle on dimensional accuracy, bead morphology, surface quality, and structural stability were evaluated. Failure mechanisms including collapse, excessive deformation, and discontinuous deposition were analyzed through visual inspection and geometric measurements. The results provide practical design guidelines for unsupported overhang fabrication in wire-based DED and contribute to improving process reliability for complex metal additive manufacturing applications.

8:40 AM
Prediction of Thermal Histories in Thin-Walled Aluminum WAAM Structures Using a Data-Driven Heat Input Model: Masayuki Matsuura¹; Shigeru Aoki¹; Kuniaki Koike²; Tomoe Yamaguchi²; Sakufu Ko¹; Yuka Yamagata¹; ¹Shimizu Corporation; ²Advanced Simulation Technology Of Mechanics R&D Co., Ltd.
    Wire arc additive manufacturing (WAAM) has the potential to reduce cost and lead time in the fabrication of large thin-walled aluminum structures. However, distortion and buckling caused by process-induced thermal histories remain major challenges. In this study, a simulation framework is proposed to predict the thermal history and thermal distortion of large thin-walled aluminum WAAM builds. A data-driven model is developed to estimate effective heat input from process parameters using thermal history data obtained from small-scale test pieces. The estimated heat input is then applied in thermal analyses of large-scale builds, and the simulation results are compared with experimental results to assess the proposed approach. This framework provides a basis for future inverse design and optimization of reinforcement structures.

9:00 AM
A Framework for Comparison of In-Situ and Finite Element Data in Wire-Arc Directed Energy Deposition: Clark Hensley¹; Jeffrey Betts¹; Elise Roberson¹; Charlotte Thompson¹; David Johnson¹; Matthew Priddy¹; ¹Mississippi State University
    In-situ monitoring (ISM) of wire-arc directed energy deposition (arc-DED) provides insight into the process parameters during deposition. This information can be used to study the final state of the printed part. One tool for using this data to determine this state is finite element analysis (FEA). The data formats used by ISM and FEA do not interoperate. This work introduces a pipeline to translate Abaqus FEA data into a format legible to Robot Operating System 2 (ROS 2) ISM systems. This data is aligned with the deposited component. Aligned data is then leveraged to perform real-time comparison between FEA simulations and in-situ arc-DED depositions. This pipeline provides a foundation for real-time decision-making during arc-DED informed by FEA. This work focuses on converting Abaqus data into the PVD (Paraview data) format, integrating this data into ROS 2, aligning data with real-time arc-DED deposition, and comparing thermal gradients of experiments and simulations.

9:20 AM
Transient Thermal Modeling and Experimental Validation of WAAM-Fabricated 316L Stainless Steel Using Julia: Abdullah All Sayeed¹; Stibitz Christin¹; Hossein Taheri¹; Bishal Silwal¹; ¹Georgia southern University
    Wire Arc Additive Manufacturing (WAAM) of 316L stainless steel was investigated using a transient two-dimensional thermal model developed in Julia with a finite-volume framework (JFVM). The model incorporated temperature-dependent heat-transfer boundary conditions to predict temperature evolution and cooling-rate behavior during GMAW-based deposition. Numerical predictions were validated against experimentally measured thermal histories obtained from deposition trials performed at wire-feed rates of 375–400 in/min and travel speeds of 30–40 in/min. Experimental measurements indicated cooling rates ranging from 65.65 to 176.5 K/s, demonstrating good agreement with the model predictions. Thermal variations influenced solidification behavior, yielding secondary dendrite arm spacing (SDAS) values of 6.32–9.38 ľm. The validated experimental–numerical framework demonstrates the effectiveness of numerical modeling for predicting thermal behavior and optimizing WAAM process parameters for 316L stainless steel components.

9:40 AM Break

10:00 AM
Assessing the Effects of Accelerated Cooling and Material Removal on Hybrid Additive-Subtractive Wire-Arc Additive Manufactured ER70S-6: Jonathan Torres¹; Aditya Pulipaka²; Ryan Smith²; Jordan Kenton¹; Jacob Aljundi²; ¹Bucknell University; ²Naval Surface Warfare Center, Carderock Division
    Wire arc additive manufacturing (WAAM) is a process where electrical arc welding is used to produce near-net shapes. Due to the mechanics of the deposition, defects and anisotropy can be induced by the process related thermal cycles. The use of an additive-subtractive hybrid wire arc additive manufacturing (HWAAM) system combines simultaneous additive deposition with subtractive CNC, resulting in faster cooling, greater control of dimensional accuracy, and reduces the need for post-processing. The combination of these leads to interactions between the individual process parameters for each operation and impart complex thermal histories, leading to variations in microstructures and mechanical properties as compared to WAAM. By producing samples of ER70S-6 under varying conditions, the effects of machining and forced cooling on the microstructure and mechanical properties can be assessed. Materials were tested in tension and fatigue, analyzing differences in mechanical behavior to link them to microstructural differences induced by variations in manufacturing.

10:20 AM
Influence of Ultrasonic Vibration on Thermal Behavior and Solidification Characteristics in WAAM 316L Stainless Steel: Poojith Chigurupati¹; Stibitz Christin¹; Haijun Gong¹; Bishal Silwal¹; Hossein Taheri¹; ¹Georgia Southern University
    The growing demand for improved microstructural control, reduced anisotropy, and enhanced mechanical performance in Wire Arc Additive Manufacturing (WAAM) has increased interest in the application of ultrasonic vibration during metal deposition. The thermal behavior, solidification, and microstructural evolution of stainless steel 316L fabricated by WAAM technique under high-intensity ultrasonic vibration were experimentally studied. Single-bead samples were fabricated by the robotic pulsed Gas Metal Arc Welding (GMAW) based WAAM system at different wire feed speeds and travel speeds. The study aims to evaluate the influence of ultrasonic excitation on melt pool geometry and its impact on directional solidification. Process stability and thermal behavior were examined using in-situ process monitoring via acoustic sensors and comparing conventional WAAM and ultrasonic-assisted WAAM. Microstructure control on dendritic morphology, grain structure and solidification pattern ware studied to elucidate the cavitation and acoustic streaming effect in WAAM fabricated stainless steel components.

10:40 AM
Mechanical and Microstructural Effects of Interlayer Machining on Hybrid Wire Arc Additive Manufacturing-Processed Aluminum: Ryan Smith¹; ¹NSWC Carderock
    Hybrid Wire Arc-Additive Manufacturing (hWAAM) couples one or more manufacturing processes with Wire Arc-Additive Manufacturing (WAAM) to improve part quality, functionality, or efficiency. When integrated with a CNC machine, hWAAM is capable of subtractive machining operations between deposited layers. The addition of interlayer machining (ILM) introduces new variables to the deposition process, such as chip load, material removal amounts, and machining frequency, which are not well explored in relation to their effect on material properties. This study focuses on the effects of ILM on thin wall aluminum ER5556 deposited material. Mechanical properties of deposited material with varied ILM parameters will be compared through sub-scale tensile testing. Variations in microstructural features including grain size, orientation, and phase distribution will be analyzed through Scanning Electron Microscopy (SEM) and optical microscopy, and effects on porosity will be determined through X-ray Computed Tomography (XCT) scanning.

11:00 AM
Oxides in Wire Arc Additive Manufacturing (WAAM): Effects on Build Quality, Mechanical Properties, and In-Process Mitigation Techniques: Abigail Fossati¹; Daniel Allford¹; ¹ARC Specialties
     Wire arc additive manufacturing (WAAM), a directed energy deposition (DED) process, generates surface oxides during layer deposition due to high-temperature exposure. These oxides can impair weld pool wetting, degrading surface quality and dimensional accuracy, while entrapped oxides form nonmetallic inclusions that reduce ductility, fatigue resistance, and overall mechanical performance. The issue intensifies with increasing part size and interpass temperatures, as prolonged heat exposure accelerates oxidation and limits natural oxide dissociation.This study examines the impact of surface oxides on mechanical properties. Several in-process mitigation strategies are evaluated and compared: oxide-reducing fluxes, mechanical interlayer cleaning, laser-based oxide ablation, and controlled additions of trace hydrogen to the shielding gas. Findings provide practical guidance for producing higher-quality WAAM components and opportunities for additional research.

11:20 AM
Mechanical Behavior of As-Built IN718 Fabricated by Coaxial Laser Wire-Directed Energy Deposition: Ajay Kushwaha¹; Amrita Basak¹; ¹The Pennsylvania State University
    This study examines the mechanical behavior, specifically, tensile and low cycle fatigue (LCF) properties of as-built IN718 fabricated using laser wire-directed energy deposition (LW-DED) with Meltio M450 machine. X-ray computed tomography revealed sub-surface gas pores and lack of fusion defects distributed throughout the as-built material. Microstructural analysis showed a mixed morphology consisting of columnar dendrites aligned with the build direction and equiaxed regions at melt pool boundaries, with Nb and Mo segregation and Laves phase formation in interdendritic regions. Room temperature tensile testing produced a yield strength of 620 MPa and an ultimate tensile strength of 903 MPa. LCF testing at total strain ranges of 0.8% and 1% demonstrated scatter in life, with reduced fatigue life at higher strain levels. Fractography, EDS, and EBSD analyses revealed that fatigue crack initiation was governed by sub-surface defects and oxide inclusions with localized strain accumulation at microstructural heterogeneities.

11:40 AM
Wire Arc Additive Manufacturing of Layered HSLA–Stainless Steel Composite Structures for Enhanced Strength–Ductility Performance: Stibitz Christin¹; Bishal Silwal¹; Abdullah Sayeed¹; ¹Georgia southern University
    Wire Arc Additive Manufacturing (WAAM) was utilized to fabricate a layered steel composite consisting of three layers of LA-100 high-strength low-alloy (HSLA) steel followed by one layer of 316L stainless steel to investigate the combined strength–ductility behavior of dissimilar steel systems. A wall structure with dimensions of approximately 206 mm × 15 mm × 150 mm was successfully deposited under controlled processing conditions to achieve sound metallurgical bonding and minimize interfacial defects. Tensile specimens extracted in both horizontal and vertical orientations were tested to evaluate anisotropic mechanical behavior, including yield strength, ultimate tensile strength, and elongation. Microstructural characterization and hardness mapping were performed to analyze grain morphology, interfacial diffusion, and phase evolution across the layered regions. The investigation established a foundation for understanding and provided insight into the mechanical behavior and interfacial characteristics of layered multi-material WAAM steel structures.