Practical MIG Welding: How a MIG Welder Works
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How a MIG Welder Works
03.12
| 00:00 | In this set of modules we're going to get familiar with the MIG welder and all of its many features and quirks, so that we have a good understanding of what makes it tick, how it can be used and what you should be looking for if you're in the market for a new machine. |
| 00:13 | To start, let's make sure we have a basic understanding of what a MIG welder does and how it works. |
| 00:19 | MIG stands for metal inert gas and is often referred to as gas metal arc welding. |
| 00:24 | This welding method is widely regarded as the simplest process to learn due to its automatic wire feed, meaning the user doesn't need to manually add filler wire. |
| 00:33 | It achieves this by using a continuous electrode in the form of thin wire fed from a spool either mounted on the handpiece or more commonly inside of the machine. |
| 00:43 | This wire is then fed through a flexible tube to the handpiece where the electrical energy is passed into the filler wire by the contact tip. |
| 00:51 | When we press the button on the handpiece, the wire will feed out from the contact tip to the workpiece. |
| 00:56 | The workpiece is also earthed to the MIG via the earth clamp, meaning that when the filler wire contacts the workpiece, the circuit is completed and current will pass through the filler wire. |
| 01:06 | This current creates heat, which causes both the workpiece and the filler wire to form a molten weld pool. |
| 01:13 | We can build up or add material to the weld pool by the addition of more filler wire if we hold the torch in the same position. |
| 01:20 | As soon as we begin moving the torch along the workpiece, the weld pool will cool and solidify, creating a strong weld made up of a mix of filler metal and base metal which is our workpiece. |
| 01:31 | The arc needs to be shielded from the contaminants in the atmosphere by an inert shielding gas that's stored in a high pressure gas bottle. |
| 01:38 | Inert simply means that the gas is non reactive or in other words it won't react with the molten metal. |
| 01:44 | The inert gas is supplied through a regulator, which controls the gas flow rate. |
| 01:49 | When we pull the trigger on the MIG handpiece, the gas flows through the MIG nozzle and over the workpiece. |
| 01:55 | All MIG welders can perform what's called flux core arc welding, which replaces the need for shielding gas with an internal core of flux in the spool of filler wire. |
| 02:05 | This is commonly referred to as gasless MIG welding and we'll expand on this later in the course as we get into the fundamentals. |
| 02:12 | With MIG being one of the simplest forms of welding, it does tend to lead to a general misunderstanding when it comes to the specific requirements of motorsport fabrication. |
| 02:21 | By following this course and getting to know your MIG welder, you'll be able to provide stronger welds and better looking welds while taking advantage of this process's ability to get the job done fast. |
| 02:32 | Before moving on, let's run over the key points in this module. |
| 02:36 | MIG or metal inert gas welding is an easy to learn welding method that uses a continuous electrode in the form of thin wire. |
| 02:44 | The wire is fed through a flexible tube to the handpiece where electrical current is passed into it, melting the filler wire electrode and forming a molten weld pool on the workpiece. |
| 02:54 | A shielding gas protects the arc from atmospheric contaminants. |
| 02:58 | The weld pool is built up by spending time in one position and once the torch is moved, the pool cools and solidifies creating a strong joint with filler and base metals. |
