Practical TIG Welding: Pulse Welding
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Pulse Welding
04.00
| 00:00 | - By this stage, you should be well aware that the TIG welding process offers a level of control that can benefit motorsport fabrication and one of the key aspects of this control is heat input. |
| 00:11 | Decreasing the overall heat input into a part can allow us to use stronger and lighter materials and the pulse function allows you to do this without risking melting holes through this thin material. |
| 00:24 | In this module, we'll show you how this works and how we can get the best out of our pulse settings. |
| 00:30 | Pulse refers to the switching between a peak amperage and a base amperage and the rate at which this happens is referred to as the pulse frequency or pulses per second. |
| 00:40 | The balance or time on setting defines how long the pulse stays in the peak part of the pulse cycle. |
| 00:47 | To demonstrate this, we'll begin by inputting the settings needed for our material which in this case is 1.6 mm thick mild steel and as we know, our rule of thumb is 40 amps per millimetre times our material thickness and this equals 64 amps. |
| 01:02 | But when we're using pulse settings this changes because we have the peak amperage and base amperage we've just discussed. |
| 01:10 | Setting these has a lot to do with the pulse balance. |
| 01:13 | For example the balance is set to 50% then this means your machine spends the same amount of time on its peak amperage as your base amperage. |
| 01:21 | In this case, the amount we want to raise the peak amperage above the 64 amps we calculated will also be the amount we want to lower the base amps. |
| 01:30 | This might sound a little confusing but essentially what we're trying to do is retain the same average amperage that we calculated out originally. |
| 01:38 | To weld this 1.6 mm material, we're going to raise our peak amps by 25% which is just 64 multiplied by 0.25 which equals 16 amps, making our peak 80 amps. |
| 01:53 | To keep the average at 64 amps, we'll lower the base amps by the same 25%, making it 48 amps. |
| 02:00 | By reducing the pulse balance, or pulse time on, we reduce the amount of heat in the part by spending less time in the peak amps and more time in the base amps. |
| 02:09 | The pulse frequency or pulses per second defines the speed of this cycle and using 1-5 Hz or pulses per second, can assist with the timing of the inclusion of your filler rod to develop a nice uniform weld appearance. |
| 02:24 | Setting our pulse frequency to 1.2 Hz, you can see the visible pulse switches. |
| 02:28 | This creates a momentary fluid weld pool that will beg for the inclusion of your filler rod as it pulses to the peak amperage. |
| 02:36 | When you're new to TIG welding then this new low frequency pulsing effect can really help assist you with your filler rod inclusion technique which will result in a better and more consistent looking weld. |
| 02:48 | If you require less heat then you can either turn down your amperage or reduce your pulse balance so that it's spending more time on the base amps and then spiking to the peak amps briefly to create the molten weld pool. |
| 03:01 | Using low frequency pulse is a powerful tool in motorsport fabrication and can assist with very low heat input into thin materials. |
| 03:09 | Turning this frequency up also has benefits by focusing the arc and pin pointing the weld pool. |
| 03:15 | Both of our machines can provide pulse frequencies as high as 500 Hz however it's very unlikely you'd ever need anything nearly this high for our purposes in motorsport fabrication. |
| 03:27 | By raising the frequency, this will also have the effect of raising the level of noise emitted by the welding process so make sure you have hearing protection fitted if you're looking to perform prolonged high frequency pulse welds. |
| 03:40 | Through setting our amperage, our balance and our frequency, we can tune our arc to suit any welding conditions we may be faced with. |
| 03:47 | As always, we recommend setting yourself up with some test materials and getting comfortable with your machine's pulse settings before cracking into any bigger projects. |
