2026 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2026): Process Development
Program Organizers: David Leigh, University of Texas at Austin
Monday 1:30 PM
August 3, 2026
Room: Pecos
Location: AT&T Center
1:30 PM
Methodology for In-Process Emissivity Estimation of Wire-Arc DED Materials Using Welded Thermocouples and IR Cameras: Charlotte Thompson1; David Johnson1; J. Logan Betts1; Clark Hensley1; Matthew Priddy1; 1Mississippi State Univeristy
Wire-arc directed energy deposition relies on thermal monitoring to ensure part quality, yet variable emissivity of materials in this highly dynamic process has a significant impact on thermal measurement accuracy. Emissivity correction methods often address individual factors independently, limiting accuracy between material, geometries, and sensing modalities. In comparison, the method proposed in this study makes an aggregate emissivity correction that can be applied robustly across non-contact thermal monitoring devices. Two Optris XI-400 IR cameras with wavelength range of 8-14µm evaluate high and low temperature ranges during deposition and multiple ROIs for emissivity mapping across the part. IR measurements are compared to welded thermocouples to determine the appropriate emissivity over small and large raster blocks as well as a hollow cylinder of ER70S-6 to evaluate varied temperature ranges and thermal histories. This work provides a framework for dynamic emissivity estimation and transferability of this methodology between geometries and temperature profiles.
1:50 PM
A Cooling Device for Drastically Reducing Manufacturing Time in Wire-DED: M. Ali Yikilmaz1; Albert To1; 1University of Pittsburgh
Wire-based Directed Energy Deposition (DED) is highly effective for manufacturing large-scale metal components due to its exceptional deposition rates. However, overall production efficiency is severely bottlenecked by prolonged inter-layer cooling periods. For instance, while depositing a single layer of Inconel 625 may take only 3 to 10 minutes, the subsequent cooling phase can exceed 30 minutes to prevent detrimental heat accumulation. To address this critical inefficiency, this study presents a novel active cooling device designed to extract heat directly from the uppermost deposited layer in a controlled manner. Utilizing an advanced chilling mechanism equipped with a conformal, flexible interface, the device seamlessly adapts to the inherent surface roughness of DED builds, effectively mimicking rapid substrate cooling. Experimental validation demonstrates a 30% reduction in overall production time. For large-scale bulk components, this thermal management approach translates to weeks of saved manufacturing time.
2:10 PM
Development of a Wire Directed Energy Deposition Worksheet for Identifying Additive Manufacturing Candidates: Jennifer Brennan1; James Burns1; Nicole Klidas1; 1Naval Nuclear Laboratory
Additive manufacturing (AM) use in commercial applications has increased dramatically in recent years. The shift was accelerated by supply chain fragility highlighted during the COVID pandemic. Manufacturers have increasingly considered the technology to replace items with otherwise long lead times. For larger components that were historically castings or forgings, wire-based directed energy deposition (DED) technology is of interest due to its ability to print large volumes of material faster than most other AM methods. However, the manufacturability considerations for DED are not necessarily obvious to the engineering practitioner inexperienced with AM technology. To this end, user guides and training are important for successful application selection. This document details development and testing of one such training tool, a worksheet for assessing the suitability of a component for manufacture via wire-based DED. The worksheet was deployed in a training session about metal AM and tested on printed components to assess its efficacy.
2:30 PM
Development of Wire-Fed Friction Stir Additive Manufacturing of AA 4043 on AA 6061 Using Conventional Knee Mill: Laura Catalano1; Cordelia Norris1; Alannah Ross1; Jonathan Dean1; Elizabeth Mamros2; John Roth1; 1John Olson Advanced Manufacturing Center, University of New Hampshire; 2Bucknell University
Wire friction stir additive manufacturing (W-FSAM) is emerging as a useful alternative to bar-fed methods of FSAM due to its continuous feeding. Proposed is a straight shaft method of continuous wire-fed FSAM, denoted as the auger method, implementable on retrofitted conventional mills, enabling easy adaptability in machine shops of all scales. This work investigates the use of readily available wire and substrate materials to showcase how the wire-fed FSAM method can be executed utilizing accessible materials for additive builds. Experiments were conducted by manually operating a Bridgeport knee mill to deposit 1.2 mm diameter aluminum alloy (AA) 4043 wire onto an AA 6061 substrate. Additively manufactured build samples were analyzed using scanning electron microscopy, microhardness testing, micro-computed tomography, and confocal microscopy to confirm that the AM material properties were comparable to the as-received wire material. Resulting properties (e.g., porosity) were also comparable to other metal formingprocesses and FSAM methods.
2:50 PM
Evaluation of Wire Arc AM Fabricated 316 L Stainless Steel Post Forging: stibitz christin1; Bishal Silwal1; 1Ga Southern Unviersity
Wire arc additive manufacturing (WAAM) offers a cost-effective and scalable route for fabricating 316L stainless steel components; however, its as-deposited columnar microstructure and thermal history can strongly influence subsequent deformation behavior. In this study, hot compression testing was performed on WAAM-fabricated 316L stainless steel to evaluate its forgeability and high-temperature flow response. Cylindrical specimens extracted from the WAAM build were compressed at selected temperatures and strain rates representative of hot-working conditions. The results showed that deformation behavior was strongly dependent on temperature and strain rate, with lower flow stress observed at higher temperatures and lower strain rates. Microstructural observations indicated deformation-induced changes in the as-built dendritic structure, including grain distortion, recovery, and possible recrystallization depending on the testing condition. These findings demonstrate that WAAM-fabricated 316L stainless steel has strong potential for hybrid additive-forging routes, where hot deformation can refine the as-deposited microstructure and improve mechanical performance.
3:10 PM Break
3:30 PM
From Defect to Feature: Controlled Porosity Patterning in Wire-Arc Directed Energy Deposition: Bemnet Molla1; Luke Hagedorn1; Christopher Williams1; 1Virginia Polytechnic Institute and State University
Wire-Arc Directed Energy Deposition (DED-Arc) is a low-cost, high-throughput additive manufacturing process capable of fabricating large-scale near-net shape metal parts. While DED-Arc is typically used to produce fully dense or contour-based structures, the ability to spatially tailor density within parts remains largely unexplored. This work presents a novel and generalizable processing technique for manufacturing millimeter-scale porous structures. The method combines waveform modulation with oscillatory toolpaths to control droplet deposition and enable tunable porosity formation. X-ray computed tomography is used to characterize the resulting multi-layer porous structure morphologies, which exhibit equivalent pore diameters of 1–8mm and porosities ranging from 20–60%. The approach is evaluated across two material systems to assess generalizability. ER5556 aluminum establishes process–structure-property relationships, while ER70S-6 mild steel demonstrates transferability across materials and power supply systems. Results show that controlled porous architectures can be produced using standard DED-Arc hardware and process parameter manipulation alone.
3:50 PM
Manufacturing Large Pressure Components with Multi Agent AM Systems: Andrzej Nycz1; Alex Arbogast1; Chris Masuo1; Michael Sebok1; William Carter1; Patxi Fernandez- Zelaia1; Caleb Massey1; Ryan Dehoff1; 1Oak Ridge National Laboratory
This work aims to establish a credible manufacturing path for full-size pressure vessels using wire-arc additive manufacturing (WAAM). A typical vessel is 3–5 m in diameter and ~10 m tall. The central challenge is scaling WAAM from subscale demonstrations to full-scale production. The first step is to manufacture a 2500lb component to better capture scale-driven effects that are not linear with small part sizes. Key challenges include increased deposition times, robotic reach, kinematic limits, and multi-agent coordination (MedUSA), severe dome overhangs requiring non-gravity-aligned deposition with improved closed-loop control, high fluidity 316LSi behavior, and amplified thermal gradients, residual stress, and distortion. This work will present a phased approach starting with a sub 500lb demonstration, overhang-focused builds, leading to an integrated ~2500lb component.
4:10 PM
Process Optimization for WAAM Deposition of High-Angle Unsupported Geometry Without Multi-Axis Positioning: Michael Sebok1; Alex Arbogast1; Chris Masuo1; William Carter1; Andrzej Nycz1; Patxi Fernandez-Zelaia1; 1Oak Ridge National Laboratory
In previous wire arc additive manufacturing (WAAM) research, the typical limit for unsupported overhang geometries is around 25-30°. Recent compensation techniques have pushed the feasible limits considerably higher, but these methods are usually validated on simplistic single bead geometries or require a multi-axis positioner. This work demonstrates that unsupported geometries can be deposited without bead failure at angles exceeding 75° with a well-tuned deposition process. This method incorporates multiple compensation methods including process control, bead adjustment, and torch reorientation. The slicing process and toolpath generation are also modified to maximize overhang stability. The process was validated on a 1” thick, multi-bead geometry approximating a spherical dome with a continuously varying overhang angle. Unlike other methods for high-angle geometries, a multi-axis positioner is not required. Experimentation was performed using 316LSi material, but all compensation methods are process agnostic and can be transferred to other metals.
4:30 PM
Wire Arc Additive Manufacturing of Functionally Graded Materials: William Carter1; Christopher Masuo1; Alex Walters1; Alex Arbogast1; Michael Sebok1; Andrzej Nycz1; Riley Wallace1; Trevor Albright2; 1Oak Ridge National Laboratory; 2University of Tennessee
Multi-material wire arc additive manufacturing allows for the creation of parts with higher cost materials only where they’re needed, such as tooling surfaces and other wear-prone areas, and lower cost materials for the bulk of a part. However, current methods result in abrupt interfaces between the materials with very little transition. This can cause incomplete bonding, especially with dissimilar material. The use of functionally graded materials allows for a smooth, more gradual transition that allows for better bonds and more seamless parts. By leveraging existing technology designed to increase deposition rate in MIG welding processes, we have created a system that allows for the deposition of functionally graded materials using a single MIG torch. An overview of the system and its progress from proof of concept to prototype system will be presented along with initial results including a part printed with a smooth transition between two different materials.
4:50 PM
Development of a Hot-Forging Wire-Arc Additive Manufacturing Tool: John Greene1; Bradley Jared1; Tyler Woodard1; Colby Hale1; 1University of Tennessee
Hot-forging wire-arc additive manufacturing (HF-WAAM) combines traditional wire arc additive (WAAM) processes and high-temperature deformation with the intention of improving the material variability and suboptimal microstructures associated with WAAM deposits. In this work, the design and fabrication of the HF-WAAM tool are presented. A pneumatic hammering system is developed and added to a custom 3-axis WAAM machine tool. The system applies in-situ deformation close to the hot, deposited weld bead with the intention of refining the part microstructure, decreasing porosity, and improving material properties. Samples are produced in ER70S-6 steel and are characterized to evaluate the impact of in-situ deformation on the WAAM process. Work will also be discussed to examine and quantify the resulting deposited material’s consistency, geometry, microstructure and properties.