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Module 2: MIG/GMAW Operation

Overview

This module focuses on hands-on MIG (Metal Inert Gas) welding technique and equipment setup. Students will learn to calibrate wire feeder tension, select voltage and amperage for given materials and joint types, apply proper gun angle and standoff distance, recognize and adapt to different transfer modes (short-circuit, globular, spray), and troubleshoot common MIG defects. By module completion, students will be able to produce consistent, sound welds with acceptable bead geometry.

Learning Objectives

  1. Perform wire feeder setup, calibration, and maintenance
  2. Select and install contact tips appropriate for wire diameter
  3. Set voltage and amperage based on base metal and joint type
  4. Explain transfer modes and recognize which mode is occurring during welding
  5. Apply proper gun technique (push angle, perpendicular to joint, consistent speed)
  6. Troubleshoot spatter, incomplete fusion, porosity, and undercut defects

Module Structure

  • Slide 1: Wire Feed System Calibration & Setup
  • Slide 2: Voltage & Amperage Selection for MIG
  • Slide 3: Gun Technique & Position
  • Slide 4: Transfer Modes (Short-Circuit, Globular, Spray)
  • Slide 5: Common MIG Defects & Correction

Assessment

  • Practical setup check: Wire feeder calibration and contact tip installation
  • Supervised welds on test coupons (flat, horizontal, vertical positions)
  • Defect identification: Photos of spatter, porosity, incomplete fusion; student diagnoses cause
  • Technique evaluation: Instructor observation of gun angle, travel speed, torch distance

Time Allocation

  • Instructor Delivery: 3 hours
  • Hands-on Practice: 5 hours
  • Troubleshooting & Defect Assessment: 2 hours
  • Total Module Time: 10 hours

Prerequisites

  • Module 1: Welding Science Fundamentals

Resources

  • Operating GMAW (MIG) system with wire feeder
  • Multiple wire types (ER70S-2, ER308L, ER5356, various diameters)
  • MIG contact tips, gas diffusers, nozzles
  • Voltage/amperage parameter table for MIG
  • Test coupons (carbon steel, stainless, aluminum)
  • Clamps and work fixtures for flat, horizontal, and vertical joint positions
  • Defect photo reference library
  • Wire feeder tension gauge (optional, for accurate calibration)
  • Measurement tools (filler gauge, depth gauge)

Module Version: 1.0 Created: 2026-03-15