2024 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2024): Special Session: Wire-fed AM I
Program Organizers: Joseph Beaman, University of Texas at Austin
Monday 1:30 PM
August 12, 2024
Room: 400/402
Location: Hilton Austin
Session Chair: Bradley Jared, University of Tennessee, Knoxville
1:30 PM
A Data Based Approach to Fault Detection and Part Qualification in Wire-arc Additive Manufacturing: William Carter1; Christopher Masuo1; Calen Kimmell1; Sudarsanam Babu2; Yukinori Yamamoto2; Riley Wallace1; Michael Sebok1; Nathan Lambert1; Andrzej Nycz1; Alex Walters1; 1Oak Ridge National Laboratory; 2University of Tennessee
Despite the capabilities of wire-arc additive manufacturing (WAAM) to create large scale parts with complex geometry, a lack of part specific qualification and certification has prevented its wide adoption in industry. By collecting and analyzing data during the build process, a digital twin of a part can be created and potential defects can be identified without the need for extensive destructive testing. This digital twin could lead to part specific performance predictions, increasing confidence in WAAM and leading to more widespread adoption in industry. A data acquisition and fault identification system currently in use on multiple wire-arc cells will be presented along with collected data that could be used to identify potential defects and qualify printed parts. The approach based on correlating the variations of arc voltage, current and speed on local and global changes in temperature and its effect on microstructure and properties will be discussed.
1:50 PM
An Evaluation of Interpass Temperature Control in Arc-DED for Distortion Mitigation using Finite Element Thermomechanical Modeling: Matthew Register1; Daniel Johnson1; Ryan Stokes1; Matthew Priddy1; 1Mississippi State University
During the Arc-DED process, nonuniform heating and cooling can lead to unwanted residual stresses and distortion in the as-built part. A fixed dwell time is often implemented allowing the part to partially cool before the next layer is deposited; however, heat accumulates in the part leading to varying weld bead sizes and heterogenous properties. Interpass temperature control adjusts the dwell time based on a prescribed minimum temperature prior to printing the next layer. This method improves thermal expansion and the heterogenous microstructure by keeping the thermal history the same for each new layer. The focus of this study will look to evaluate both methods of dwell time implementation using finite element thermomechanical models to determine the optimal interpass temperature and dwell time for maraging 250 steel. Comparisons from the predicted distortion to experimental substrate distortion will be used to determine which method is most useful prior to printing the part.
2:10 PM
Demonstration of a Wire-arc DED Process Optimization Framework: Jack Canaday1; Austen Thien1; 1Naval Surface Warfare Center Carderock Division
Determination and validation of processing parameters for directed energy deposition (DED) is critical to build success but requires time, capital, and experience for each new material system and hardware configuration. To promote effective parameter development, a framework was developed for statistical optimization of a wire-arc DED process using nickel-aluminum bronze (NAB) feedstock and demonstrated to achieve an optimized set of processing parameters. Findings from the optimization trial including evaluation of optimization and process modeling approaches as well as the quantitative metrics employed will be presented. A demonstrative article was generated using the optimized condition for comparison to trial conditions. The described framework is intended to be tailorable based on process, material, and application requirements through selection of process inputs, defined analytical criteria, and experimental geometry investigated.
2:30 PM
Design Strategies for a Wire Arc Additive Manufactured Hip Impeller Using a Multi-robot WAAM System: Christopher Masuo1; Andrzej Nycz1; Joshua Vaughan1; Michael Sebok1; William Carter1; Alex Walters1; Nathan Lambert1; Riley Wallace1; Canhai Lai1; 1Oak Ridge National Laboratory
Wire arc additive manufacturing (WAAM) can be used to fabricate a large-scale impeller with the benefits of reducing material waste and production time. Additionally, the impeller design can be modified for a hot isostatic pressing (HIP) process to improve the mechanical properties and reduce the tooling cost. For large-scale impellers, such as a hydropower impeller, a multi-robot WAAM system can be used to further improve the overall production time. However, this introduces challenges in allocating evenly distributed deposition tasks for the individual robots as well as avoiding robot-to-robot collisions. In this work, varying design strategies were evaluated to alleviate these challenges. Initial tests were conducted using simulation. The best design strategies were then chosen to manufacture the large-scale HIP impeller using MedUSA, a multi-robot additive manufacturing system.
2:50 PM
Development of a Closed-Loop Control System for Contact Tip to Work Distance and Interpass Temperature in Wire Arc Additive Manufacturing of Architectural Facades: Yuka Yamagata1; Takayuki Sagawa1; Shigeru Aoki1; Takeyuki Abe2; Jun'ichi Kaneko2; 1Shimizu Corporation; 2Saitama University
This study introduces a closed-loop control system for Contact Tip to Work Distance (CTWD) and interpass temperature in Wire Arc Additive Manufacturing (WAAM), aimed at enhancing the production of architectural facades. By integrating feedback from laser-profiled measurements and thermographic cameras, the system dynamically adjusts CTWD and temperature settings, addressing the challenges of inconsistency in layer deposition and thermal accumulation. The implementation of this system enabled the automated manufacturing of aluminum mullion with a height of 855mm. Trials confirmed the system’s ability to maintain consistent layer quality and thickness distribution, while effectively preventing defects such as voids. The results demonstrate that precise control of CTWD and interpass temperature is crucial for optimizing the quality and reproducibility of WAAM components, making it a valuable advancement for the construction industry in customizing large-scale metal structures.
3:10 PM Break
3:40 PM
Enhancing Microstructure and Mechanical Properties of 7075 Aluminum Walls Using a Hybrid Wire-arc Directed Energy Deposition and Friction Stir Process: Dinh Son Nguyen1; Soumya Sridar1; Wei Xiong1; Albert To1; 1University of Pittsburgh
High-strength 7075 aluminum alloys possess excellent strength and fatigue resistance amongst the lightweight metal alloys. Wire-arc directed energy deposition (wire-arc DED) is characterized by low-cost feedstock, high material utilization, and high production efficiency. However, fabricating Al 7075 components via wire-arc DED is challenging because the material is difficult to weld, leading to issues such as excessive amount of porosity and large columnar grains, which result in lower strength and ductility. Meanwhile, friction stir processing (FSP) is capable of refining the grain structure of aluminum alloys. This work attempts to enhance microstructure and mechanical properties in an Al 7075 wall by means of an integrated hybrid wire-arc DED/FSP/milling system. Using this system, the different processes are applied in sequence to process every layer of the build. Our results show that the hybrid process can reduce porosity, refine grain structure, and improve mechanical properties.
4:00 PM
Enhancing Stability and Quality in Laser-wire Directed Energy Deposition Through Dual-control Algorithms: Hyub Lee1; Seong Hun Ji1; Jongcheon Yoon1; Durim Eo1; Dongseok Kang1; Simo Yeon1; Yong Son1; 1Korea Institute of Industrial Technology
The Laser-wire Directed Energy Deposition (LW-DED) process is increasingly favored for its cost efficiency compared to the powder-blown DED method. However, LW-DED requires relatively complex control due to the continuity of the feed material. In powder-blown DED, suboptimal heat input might cause defects like lack of fusion or keyhole porosity, but these usually don't halt the process. In contrast, inappropriate parameters in LW-DED can cause stubbing, where un-melted wire bends under load, or dripping from excessive melting, both of which critically affect bead quality and can terminate the process. This presentation introduces a control algorithm for LW-DED process designed to simultaneously adjust laser power and wire feed rates. This dual-control strategy ensures a consistent melt pool size and continuous, stable bead formation, which prevents the process failure effectively.
4:20 PM
Evaluation of In-situ Monitoring Data with Non-destructive Evaluation for Laser-wire DED Ti6Al4V: Jack Canaday1; Keegan Muller2; 1Naval Surface Warfare Center Carderock Division; 2Vision Point Systems
In-situ monitoring (ISM) technologies are viewed as a potential technique to reduce qualification and certification burden for utilization of large-scale directed energy deposition (DED) processes. In this study, a representative component geometry was deposited using laser-hot wire DED (LHW-DED) with Ti6Al4V. An in-situ monitoring dataset comprising major processing variables was generated during deposition and X-ray computed tomography (XCT) was performed following deposition. The effectiveness of ISM for the detection of discontinuities induced during DED processing was explored using ground truth XCT data. Findings were gathered related to the effectiveness of selected sensor modalities and process signatures.
4:40 PM
Exploring Toolpath Strategies in Wire-arc Directed Energy Deposition for Enhanced Material Properties in Inconel 625: Xavier Jimenez1; Albert To1; 1University of Pittsburgh
Wire-arc directed energy deposition is a technology that uses an electric arc to melt the feedstock wire on a layer-by-layer basis to create 3D structures. Traditionally, toolpaths in wire arc are divided into two subcategories: single track and meander. In this work, we analyze the effect of toolpath selection and meander width have on material properties and cooling rate for parts printed using Inconel 625. The results show that single tracks have a continual cooling period, while meander walls experience reheating caused by the back-and-forth movement of the torch. The wall width is the primary factor influencing the effectiveness of the reheating effect in material property improvement. Correlations between mechanical properties and cooling rates are explored to elucidate the controlling mechanisms. A transition zone is identified where the reheating facilitates complete solidification and modifies the grain structure and mechanical properties.