Session: 

Paper Number: 173061

Investigation of Bead Geometry Through Parametric Study in Cold Metal Transfer Based Wire Arc Additive Manufacturing of Inconel 718 

Wire arc additive manufacturing (WAAM) technology has emerged as a highly advantageous production method due to its high deposition rates, particularly when high-cost material for large-scale components is needed. Cold metal transfer (CMT) is one of the most advanced variants of WAAM, utilizing a reciprocating wire feeding motion that retracts the wire immediately upon short-circuit contact with the workpiece. This mechanism reduces heat input and promotes arc stability. Inconel 718 is a nickel-based superalloy renowned for its high strength, excellent corrosion resistance, and ability to maintain mechanical properties at elevated temperatures up to around 700°C. It is widely used in aerospace, power generation, and chemical processing industries. Due to its weldability and thermal stability, Inconel 718 is well-suited for advanced manufacturing techniques such as WAAM, enabling efficient production of large-scale, complex, and high-performance components. However, careful control of process parameters is necessary to avoid defects such as hot cracking during fabrication. This research demonstrates a unique approach for analyzing and optimizing the process parameters in single-bead geometries of CMT-based WAAM of Inconel 718.

The combined use of the Fronius TPS 4000, Gefertec arc605 CNC-controlled system, and Siemens NX CAD software supports precise CMT-based deposition and real-time control of welding parameters. The characterization methodology combines precision machining with high-resolution imaging to accurately characterize bead geometry—specifically height, width, and contact angle—in the steady-state phase of deposition. Additionally, optimized parameters from single-bead geometries are used for multi-bead samples of Inconel 718. Semi-automatic grinding and polishing of the samples were then performed to control repeatability and reliability in porosity analysis and hardness data. During the welding process, monitoring and controlling parameters such as voltage, current, torch travel speed, and interlayer temperature enable the optimization of the deposition procedure. The voltage and current are modified by performing single bead depositions at 6-11 m/min wire feed speeds. The travel speed of the welding torch is tested from 650 mm/min up to 1100 mm/min, directly affecting the heat input throughout the printing process. The interlayer temperature also varies from 100-400 °C to avoid hot cracking and to observe changes in the resulting material's substructure and mechanical properties.

The findings indicate that voltage and current are the most significant factors influencing the contact angle between the bead and the substrate during deposition. The travel speed of the welding torch is shown to have the most significant effect on the deposition's width and height. The heat input for every set of parameters is also calculated to monitor its effect on hot cracking, with preliminary results showing the least amount of hot cracking occurring when the heat input is near 200 J/mm. The results further demonstrate that the proposed methodology decreases the time and dataset size necessary to identify the optimal WAAM process parameters to effectively mitigate the occurrence of hot cracking.

Presenting Author: Devyn Duryea OMIC R&D

Presenting Author Biography: Dr. Devyn Duryea is a Research Associate at OMIC R&D, and brings expertise in optics and photonics, with a strong research background in laser manufacturing. During his PhD at Oregon State University, he worked in a laser manufacturing lab, using ultrafast lasers to create nanoparticle and 2D nanomaterial colloids—pioneering research aimed at developing inks for printed electronics. Now at OMIC, he has been focused on advancing research in wire arc additive manufacturing and very high cycle fatigue testing.

Authors:

Devyn Duryea OMIC R&D
Chuankai Song OMIC R&D
Trent Lamont OMIC R&D
Sierra Repp OMIC R&D
John Timmerman OMIC R&D
Zack Kane OMIC R&D
Tai Adams OMIC R&D
Cole Erhardt OMIC R&D
John Isherwood OMIC R&D
Zane Strassheim OMIC R&D
Mostafa Saber OMIC R&D