MIG Welding
MIG (Metal Inert Gas) and MAG (Metal Active Gas) welding are arc welding processes that use a continuous consumable wire electrode and shielding gas to produce strong, durable welds. MIG/MAG is the most widely used welding process in sheet metal fabrication.
See also: Joining for the full joining workflow and other joining methods.
When to Use MIG/MAG Welding
Use MIG/MAG welding when:
- Continuous weld seams are required (fillet, butt, lap, or T-joints)
- Structural strength is needed across the full joint length
- Joining steel, stainless steel, or aluminium
- Medium to high production volumes where speed matters
Step-by-step
MIG/MAG welding runs as part of the automatic Joining workstep — there is nothing to click to trigger it directly. To choose MIG/MAG welding as the joining method on an existing Joining node:
- Open the Graph View and locate the automatically created Joining node for the article.
- Right-click the Joining node and select Edit process.
- Choose Arc welding (MIG/MAG) as the joining method.
- Confirm your choice. WSi updates the Joining node with the new method.
Result
After running MIG/MAG welding:
- A Joining node appears in the Graph View, connected from the upstream cutting or bending nodes
- The Tree View shows each joining step with its geometry and any comments
- Export data includes joining instructions — weld path, position, and parameters for each step
Other Joining Methods
WSi supports multiple joining methods:
- Spot Welding — discrete point welds for high-volume production
- TIG Welding — high-precision welds with a non-consumable tungsten electrode
- Brazing and Bonding — non-weld joining for specific material combinations
See Joining for the full overview.
WARNING
Joining is an optional module. If the welding module is not licensed, the Joining workflow is blocked. Contact your sales representative at WSoptics to obtain the welding licence.
Technical Background
MIG (Metal Inert Gas) and MAG (Metal Active Gas) welding are both arc welding processes that differ primarily in the shielding gas used. In MIG welding, an inert gas (typically argon or argon-helium mix) shields the weld pool, making it suitable for non-ferrous metals such as aluminium and stainless steel. In MAG welding, an active gas (primarily carbon dioxide or CO₂ mixed with argon) participates in the arc chemistry; it is the standard choice for carbon steel because the reaction between the arc and CO₂ generates higher heat input, producing deeper penetration and faster travel speeds.
In both processes, a continuous wire electrode is fed through the welding torch at a rate matched to the travel speed. The arc melts the wire and the base metal edges simultaneously, forming a fused joint as the pool cools. The shield gas flows through the torch nozzle, displacing atmospheric air and preventing oxidation of the molten metal. MIG/MAG is a semi-automatic or automatic process — the operator guides the torch along the joint line while the machine controls wire feed, gas flow, and voltage.
Key process parameters are: wire diameter (typically 0.8–1.2 mm for sheet metal), wire feed speed (determines current), shielding gas composition and flow rate, and travel speed (determines heat input and bead profile). The heat-affected zone (HAZ) in MIG/MAG is relatively narrow, and the weld cools quickly due to the high thermal conductivity of the base metal. Spray transfer mode (where the wire melts into droplets projected across the arc) is used for thicker materials, while short-circuit transfer is used for thin sheet to prevent burn-through.