MIG welding (Metal Inert Gas welding) is the "all-rounder" in the welding industry. It uses a welding wire as the electrode and protects the welding process with inert gases such as argon and helium. Its continuous wire feeding design is user-friendly, allowing even beginners (including female trainees) to quickly master it. However, attention should be paid to sparks and necessary safety equipment.
During welding, the welding wire is fed from the spool through the drive roller into the welding torch. An electric arc is ignited between the tip of the welding wire and the workpiece, and the inert gas isolates the air. Using reverse polarity DC (welding wire positive, workpiece negative), the arc is stable and allows for cathodic sputtering to remove aluminum and magnesium oxide films. In practice, the molten droplet transfer requires precise control of electromagnetic force and surface tension, resulting in a uniform weld seam after cooling, a process akin to precise baking.
1. Wide applicability: Can weld aluminum, copper, stainless steel, etc., with less oxidation and burning loss, resulting in a bright surface after polishing, such as on aluminum alloy bicycle frames;
2. High efficiency: Continuous wire feeding eliminates the need for frequent electrode changes, making it three times more efficient than traditional welding methods for mass production (e.g., car exhaust pipe welding);
3. Excellent weld quality: Stable arc, minimal spatter, uniform fish-scale pattern without pores or cracks, ensuring strength;
4. Lower cost: Simple equipment, friendly to small and medium-sized enterprises, and more cost-effective for trainees using it for agricultural machinery and truck repair;
5. High cleanliness requirements: The welding wire and workpiece surface must be clean (oil and rust can easily cause pores);
6. Diverse transfer modes: Short-circuit transfer (thin plates 0.8mm), spray transfer (medium-thick plates 3-10mm), and pulsed spray transfer (aluminum 0.5mm thin plates), the latter producing thin and strong welds, like fine sewing.