The Effect of Electrode Diameter on Single-Track Morphology and Process Window in Powder-Bed Arc Additive Manufacturing

Abstract

Powder-bed arc additive manufacturing (PBAAM) is a low-cost alternative powder bed fusion process that uses a TIG arc as heat source. This study systematically investigates the effect of electrode diameter (φ = 0.6, 0.8 and 1.0 mm) on single-track morphology and process window in inclined-bed PBAAM of 316L stainless steel powder. Twenty-seven full-factorial combinations of three current levels (I = 20, 25, 30 A) and three travel speeds (v = 2, 3, 4 mm/s) were evaluated using an image analysis framework based on Otsu thresholding with expert manual correction. Maximum gap length (L_gap) and width coefficient of variation (CV = σ_w/w̄) metrics were compared across six threshold scenarios (S1–S6); S5 (L_gap) = 0.50 mm, CV = 0.15) was identified as the most appropriate combination based on physical justification and literature consistency. Process map analysis revealed travel speed v as the most critical parameter governing the process window: at v = 2 mm/s, 9/9 combinations (100%) produced continuous tracks; at v = 4 mm/s, only 5/9 (56%) were continuous. Multiple linear regression models achieved R² = 0.626 for mean track width w̄ and R² = 0.562 for CV. Electrode diameter φ significantly affects track width (β_φ = 0.762, p = 0.019) but has no significant linear effect on width uniformity CV (p = 0.955); CV is primarily governed by I and v. The φ = 0.8 mm electrode confined all Fragmented/Balling combinations to v = 4 mm/s only and produced approximately 35% lower mean CV (0.184) than the other two electrode diameters for continuous tracks.

Keywords

• Electrode diameter
• Single-track morphology
• Process window
• Image analysis
• Regression model
• 316L stainless steel

Supporting Institution

Kafkas University

Project Number

2023-FM-40

Ethical Statement

Ethics committee approval was not required for this study because of there was no study on animals or humans.

Thanks

This study was supported by the Scientific Research Projects Coordination Unit of Kafkas University under project number 2023-FM-40. The authors gratefully acknowledge this financial support.

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