What types of welding are best suited for sheet metal fabrication projects?

Quick Answer

The best welding process depends on material and application: TIG (GTAW) for thin stainless and aluminum with cosmetic welds, MIG (GMAW) for thicker steel with high deposition rates, spot welding (RSW) for high-volume production of lap joints, and laser welding for precision applications requiring minimal heat input. For most custom sheet metal fabrication, TIG and MIG account for 85% of all welding.

TIG Welding (GTAW)

Tungsten Inert Gas (TIG) welding uses a non-consumable tungsten electrode and a separate filler rod. It produces the highest quality, cleanest welds with excellent control over the weld pool. Best for: stainless steel (304, 316) 0.5-3mm, aluminum 1-4mm, and all thicknesses where appearance matters. TIG welds require minimal post-weld cleanup. Typical welding speed: 50-200 mm/min. Requires skilled operators.

MIG Welding (GMAW)

Metal Inert Gas (MIG) welding uses a consumable wire electrode that feeds automatically through the welding gun. It is faster than TIG and easier to learn. Best for: mild steel 1.5-6mm, thicker sections requiring high deposition, and structural welds where appearance is less critical. MIG welding deposition rates: 2-8 kg/hour depending on wire diameter and settings. Gas shielding: 75% Argon + 25% CO2 for steel.

Resistance Spot Welding (RSW)

Spot welding is the most efficient method for joining overlapping sheet metal (0.5-3mm each). Two copper electrodes clamp the sheets and pass a high current (8,000-15,000 A) for 0.1-0.5 seconds, creating a fused nugget at the interface. Weld time: 1-3 seconds per spot. Ideal for high-volume production of enclosures, automotive panels, and consumer products. Spot welding is fully automated with robotic systems.

Why Choose SOMI Custom Parts

At SOMI Custom Parts, we offer TIG, MIG, and spot welding capabilities with certified welders for each process. Our TIG welders specialize in food-grade and medical-grade welds with sanitary finishes. Our MIG welding department handles structural steel fabrications. For high-volume projects, we can integrate robotic welding for consistent quality and maximum throughput.

Case Study

A food processing equipment manufacturer required 500 stainless steel hoppers with sanitary TIG welds (no pits, no cracks, Ra 0.8 finish). SOMI's certified TIG welders completed all welds using 316L filler rod with argon backing gas to prevent oxidation. The welds passed dye penetrant inspection and surface finish verification. The client's FDA auditor approved the fabrication on the first visit.

Industry Data

TIG welding accounts for 25% of sheet metal fabrication welding, MIG for 60%, and spot welding for 15% (American Welding Society, 2025). Robotic welding has grown 35% over the past 5 years and now accounts for 30% of all production welding, with ROI typically achieved in 12-18 months for high-volume applications.

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