Practical MIG Welding: Pulse Welding
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Pulse Welding
03.31
| 00:03 | -00:00:00,300 --> 00:00:03,840 While MIG welding is known for being a very quick welding method, this does come with the downside of high heat input as discussed in the last module. |
| 00:07 | Decreasing the heat input into a part requires either less time welding it or a reduced amount of overall current. |
| 00:14 | The pulse function that's included on more advanced machines allows you to do this. |
| 00:18 | If you're lucky enough to have a machine with this function, then you'll have a huge head start on controlling the heat input whilst maintaining the weld speed and appearance. |
| 00:27 | Pulse refers to repeatedly switching between a peak amperage and a lower base amperage. |
| 00:33 | The rate at which this happens is referred to as the pulse frequency or pulses per second. |
| 00:38 | The balance or time on setting defines how long the pulse stays in the peak part of the pulse cycle. |
| 00:45 | Thinner sections of material benefit from a reduced risk of burn through and warping by controlling the heat via this pulse welding method. |
| 00:51 | This control often means we can use a larger wire diameter which allows for faster wire feed and travel speeds, increasing productivity while reducing the heat input that would usually lead to stress and distortion of the metal. |
| 01:03 | To add to this, pulsed MIG welding can minimise the amount of spatter due to the pulse function cutting off the wire droplet and placing it into the weld pool rather than the wire hitting the weld pool like it would in a non pulsed mode. |
| 01:16 | Lastly, pulsed MIG welding can be beneficial for out of position welding due to the lower heat input. |
| 01:22 | If you have a machine with a pulsed function, then it's definitely worth spending some time setting it up and experimenting with it to see the difference it can make to your finished welds. |
| 01:32 | Manipulating the available settings can make dramatic differences to the finished weld and understanding them will take a little practice. |
| 01:39 | Complicating things a little more, each manufacturer will use different terms and buttons to set the parameters of a pulsed function. |
| 01:46 | You'll most likely have a background amperage setting to set the background current, a peak amperage setting to set the pulse current that will be doing the penetrating, a pulse frequency that will range from around 20 to 400 pulses per second, and a pulse time on that will allow you to modify the balance of the pulse cycle by adjusting the amount of time each pulse stays in the base or peak of its cycle. |
| 02:09 | To add further complication, some advanced machines may also offer a double pulse function which adds a second slower pulse modulation that will typically be in the range of 0.5 to 5 Hz on top of the standard pulse process. |
| 02:23 | This creates a rhythmic variation in the welding current, resulting in that distinctive stacked dime appearance to the finished weld. |
| 02:29 | It's particularly useful for improving weld aesthetics, controlling heat input and enhancing weld pool fluidity, especially in materials like aluminium and stainless steel. |
| 02:38 | Having said that, MIG welding these materials in motorsport isn't common or recommended but it can be handy for industrial applications such as boat building and large scale manufacturing where TIG welding is just too slow to be viable. |
| 02:50 | When you're experimenting with pulse welding, it's important to set yourself up with some test material and get comfortable with your machine's pulse settings before cracking into any large projects. |
| 03:01 | MIG welding is known for its speed and efficiency but it can generate excessive heat, affecting the dimensions of critical parts, particularly in thin sheet metal. |
| 03:09 | The pulse function allows for better heat control by switching between peak and base amperages, meaning that the average current is reduced compared to conventional MIG welding. |
| 03:18 | This control is beneficial for thin materials, reducing burn through and warping, while potentially allowing us to use larger diameter wire for increased productivity and speed. |
