Chapter 5: Welding Machines

An illustration of a simple welding power source with power cable. This example is a green machine with wheels attached to the back so the machine can be moved around, but it has two legs on the front for stability. Two electrical receptacles, one positive and one negative, are on the front of the machine where the welding leads plug in. A knob on the front allows the welder to adjust the welding amperage.
Welding Machine Example / Photo Credit: alefonte, Pixabay License

Overview

A young welder uses a 110V MIG welding machine in her garage to tack together a frame and roll cage for a homemade go-kart. A mobile repair welder uses an engine-driven “stick” welding machine to make repairs on an excavator bucket. In a small fabrication shop, a grizzled old welder uses an enormous old TIG machine, its control panel bristling with knobs, dials, and switches, to weld flanges on some stainless-steel pipe sections. While in another shop, a young man, only a couple years out of welding school, takes his seat at his station next to a brand-new inverter TIG welder, its digital display lighting up as he flicks on the power switch. Each of these welding scenarios is different, and each of the welding machines mentioned has different capabilities and was designed to meet different needs.

The development of welding technology over the last century is a fascinating subject. Arc welding, in its different forms, makes up the majority of the welding done in industry today. Arc welding machines range from very simple to extremely advanced. Even so, there are some features and characteristics that all welding machines have in common.

In this chapter, you will learn about some of the different welding machines that you may encounter on the job. You will be introduced to the basic concepts of electricity and welding power. You will become familiar with the different types of welding machines and their operation. You will also identify certain components of welding systems.

Objectives

After completing this chapter, you should be able to:

  • List the components of electricity.
  • Identify the three welding polarities.
  • Describe Constant Current and Constant Voltage and how they are used in welding.
  • List different types of welding power sources.
  • Define Duty Cycle.

Key Terms

  • Alternating Current (AC)
  • Amps/Amperage
  • Arc Length
  • Circuit
  • Conductor
  • Constant Current (CC)
  • Constant Voltage (CV)
  • Direct Current (DC)
  • Direct Current Electrode Negative (DCEN)
  • Direct Current Electrode Positive (DCEP)
  • Duty Cycle
  • Electrode Lead
  • Filler Metal
  • Flux Cored Arc Welding (FCAW)
  • Gas Metal Arc Welding (GMAW)
  • Gas Tungsten Arc Welding (GTAW)
  • Insulator
  • Manual Process
  • Metal Inert Gas (MIG)
  • Ohms
  • Open-circuit Voltage
  • Semi-automatic Process
  • Shielded Metal Arc Welding (SMAW)
  • Tungsten Inert Gas (TIG)
  • Volts/Voltage
  • Watt/Wattage
  • Weld Pool/Weld Puddle
  • Wire-Feed Speed (WFS)
  • Workpiece Lea

Attributions

  1. Chapter opening image: image released under the Pixabay License

License

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Introduction to Welding Copyright © by Washington State Board for Community and Technical Colleges is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.