Influence of Wire Feeding Angle on Droplet Transition Behavior And Process Stability in Wire-Laser Additive Manufacturing

01 Introduction

In the aerospace, energy, and automotive industries, additive manufacturing (AM) technology has garnered significant attention due to its ability to fabricate complex geometries. However, the stability of droplet transition during the AM process directly determines the fatigue performance and forming quality of the final components. As a key process variable, the wire feeding angle not only changes the interaction area between the laser and the wire but also affects the mechanical balance of the liquid bridge. This study focuses on how the wire feeding angle induces transitions in droplet transition modes through a thermo-mechanical coupling mechanism.

02 Overview

A comprehensive fluid dynamics model was established to study the evolution of liquid bridge morphology and molten pool dynamics at different wire feeding angles ranging from 25° to 65°. The study found that as the wire feeding angle increases, the liquid bridge stability transitions from a stable state dominated by surface tension (25° and 45°) to an unstable state dominated by inertia and gravity (65°). The instability of the liquid bridge is mainly caused by the mismatch between the melting rate and the wire feeding rate.

03 Figure Analysis

• Figure 1. Evolution of maximum melt temperature and molten pool volume under different wire feeding angles: Shows that the maximum temperature and melt volume reach their peak at a 65° wire feeding angle due to the Brewster angle effect, with the curves exhibiting intense fluctuations.

• Figure 2. Evolution of melt flow in the center section under different wire feeding angles: Compares the melt flow fields at 25°, 45°, and 65°. At 65°, two vortices exist within the liquid bridge, with the flow velocity concentrated in the center, increasing instability.

• Figure 3. Distribution of temperature gradient and velocity near the liquid bridge area at 90 ms for different wire feeding angles: High-efficiency convective heat transfer occurs at 25° and 45°, while low-efficiency heat conduction occurs at 65°, leading to a significant decrease in the local melting rate.

• Figure 4. Geometric characteristics of liquid bridge stability under different wire feeding angles: Quantitative characterization of stability through area ratio and equivalent aspect ratio. Irreversible breakage of the liquid bridge occurs at 65°.

04 Conclusion

The range of 25° and 45° constitutes a relatively stable process window. When the angle increases to 65°, weakened heat transfer leads to a reduction in the local effective melting rate, and the mismatch between melting and wire feeding triggers unstable breakage.

Original link: https://doi.org/10.1016/j.jmapro.2026.03.031