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A droplet is a liquid metal droplet that forms at the end of the welding wire during gas shielded welding and transitions into the molten pool. The process by which the droplet is transferred to the molten pool through the arc space is called droplet transfer. The droplet transfer mode has a significant impact on the stability of the welding process, weld shape, spatter formation, and welding quality. Understanding the droplet transfer mode is important for mastering the metal arc welding process. The droplet transfer mode in gas metal arc welding (GMAW with solid wire) is determined by the welding current and voltage; in order of increasing welding parameters, it is Short Circuiting Transfer, Globular Transfer, and Spray Transfer. The droplet transfer mode can be observed using a high-speed camera with strong lighting. 1. Short-circuit transition refers to the situation where the droplet at the end of the welding wire comes into direct contact with the molten pool, resulting in a short circuit; under the combined effect of intense overheating (when the current reaches its maximum value) and magnetic contraction, the droplet breaks apart and transitions into the molten pool. Short-circuit transfer enables stable metal droplet transfer and a stable welding process under low-power short arcs (low current, low voltage), making it suitable for all-position welding of thin sheets or for welding materials that require low heat input. The welding current required to achieve a short-circuit transition is generally not more than 200A. 2. Drop transfer (also known as particle transfer) occurs when the arc length exceeds a certain value; the droplet can maintain its growth at the end of the welding wire due to surface tension. When the forces acting to pull the droplet downward (such as gravity or electromagnetic forces) exceed the surface tension, the droplet separates from the welding wire and transfers freely into the weld pool, without causing a short circuit. During droplet transfer, the diameter of the droplet is larger than the diameter of the wire used. The conditions for achieving droplet transfer are a welding current of 200A–300A for 100% CO2 gas, and 200A–280A for argon-enriched mixed gas. 3 Jet transition (also known as jet transfer) is a process in which the droplets are in the form of small particles (with a diameter smaller than that of the welding wire), and they move rapidly through the arc space in a jet-like manner to reach the molten pool. The size of the droplet decreases as the welding current increases. At a constant arc length, when the welding current increases to a certain value, the spray transition state occurs. It should be emphasized that, in addition to a certain current density, the occurrence of a jet transition also requires a certain arc length (arc voltage); if the arc voltage is too low (the arc length is too short), then no jet transition can occur, regardless of the value of the current. The jet transition is characterized by fine droplets, a high transition frequency; the droplets move at high speed along the axis of the welding wire toward the weld pool. It offers advantages such as stable arc, low spatter, deep penetration, good weld appearance, and high production efficiency. The condition for achieving a jet transition is a welding current of 280A to 350A with an argon-rich gas mixture.