Have you noticed the feature of BURNBACK MIG? Today we will talk about it...

So...What is Burnback?

Burnback happens when your wire arcs at the opening of the contact tip and burns back into it, welding itself to or inside the tip. Burnback is specifically a MIG problem, as it only occurs with a continuously fed wire through a small contact tip opening.

What Causes Burnback?

*Wire feed speed is too slow

A slow wire feed speed means that the arc is melting the wire faster than it’s coming out of the machine. If it’s burning faster, it’s only got one place to go, and that’s back up the wire and into the contact tip. Holding the torch too close to the workpiece. The closer your torch is to the workpiece, the easier it is for your arc to jump up into your nozzle and contact tip.

*Erratic wire feeding

Erratic wire feeding usually happens because the filler wire hasn’t been tensioned correctly. If you’ve added too much tension, the wire will struggle to feed, and it’ll jump or bounce between feeding and becoming stuck. Those periods where the wire is stuck create the perfect opportunity for the arc to burnback.

*A bad grounding

If your earth clamp loses contact, the voltage will drop, but the wire will keep feeding, which causes burnback.

*Wrong contact tip size

If you’re using a contact tip that’s too small, your wire is going to stick and drag through the opening. If the tip is too big, the wire has space to rattle around in it. Either way, you end up with poor conductivity and a recipe for burnback.

*Damaged or wrong liner

In the same vein as the contact tip, if your liner isn’t the same size as your filler wire, it’s going to drag or be loose. The other issue with liners is that they can become damaged, kinked, or be cut too short. All these things cause wire feeding issues, which can lead to burnback.

*Having the burnback control turned up too high

If you have an adjustable burnback setting on your welder and you left it set to the max, you’ll likely be flying through contact tips.

How to prevent BURNBACK

1. Check your settings

Your voltage and wire speed work hand in hand, so your wire feed speed should be fast enough to keep up with your heat. The recommended settings are a great starting point for a wire feed speed that’ll match the voltage.

2.Use the correct consumables

The state of your consumables will dictate the state of your weld, so get the right ones. Your contact tip and liner should match your wire size, and all of it should be clean. Anything less, and you’re going to have problems.

3.Watch your wire tension

It seems like such a small issue, but wire that isn’t tensioned correctly can cause a lot of problems. The wire should feed smoothly, but it shouldn’t be so loose that it slips. 

4.Get a good earth

Having a good ground is essential for any weld. The earth clamp completes your electrical circuit; without it, the machine won’t arc. That’s why you need to make sure your clamp has been attached to clean, bare metal, and it isn’t going to be bumped or moved.

5.Maintain your torch distance

For most MIG welding, your wire should stick out of your torch nozzle by roughly 1cm. That means your torch should be at least 1cm away from the joint. Too far away and you’ll get excessive spatter, too close and you’ll weld your contact tip.

6.If you have an adjustable burnback control, adjust it.

Don’t leave your burnback set all the way on or all the way off. Neither of those is going to be ideal for most welds. 

Somewhere in the middle will work well and leave the right amount of wire on most metals and applications.

The Burnback Controls

If a machine didn’t have any burnback, the filler wire would stick to the weld when you released the torch trigger. The arc would stop at the same time as everything else, leaving your wire where it was – in the weld joint.

That’s where the burnback comes in. It allows the wire to remain electrically charged for a brief moment, meaning you don’t have to cut it free after every weld.

Even if you don’t have an adjustable setting, that doesn’t mean the machine doesn’t have any burnback. It just means that it has a built-in burnback amount.

The burnback controls on our MIG-250 welder can be adjusted from 1-10.

1 would be almost none, and 10 would be the max amount.

Setting your machine to 1 and having no burnback means you run the risk of the wire sticking out too far and becoming stuck in the weld.

Setting your machine to 10 and having the max burnback means you’re probably going to end up self-inflicting the actual welding problem of burnback.

We recommend setting your burnback to 5, or in the middle range, for the best results.

What you set your burnback controls to comes down mostly to personal preference. How far do you want your wire to stick out of the torch when you stop welding? If the answer is a lot, turn your burnback down. If the answer is not a lot, turn the burnback up.