Wire melting issues

[Hood]

I am having problems with my EWM Phoenix with an EWM PC2 push pull torch.
Initially I had two problems, one was the arc was sort of bouncing and I found out the pins on the plug had corrosion on the motor power pins, I replaced the pins and it cured that problem.

The second problem is however still there and I am at a loss as to what could be causing it. That problem is I am welding away great then all of a sudden I will get burnback but not like the normal burnback where the wire melts in the contact tip. The wire is actually melting further down in the neck, sometimes it can be close to the end and other times it can be further back in the neck liner. Sometimes it will weld itself inside the brass liner which means it is scrap and it is getting a real PITA as I am going through the brass liners fast.

Anyone have an idea what the problem could be?

Here are some pics of what happens.

 

[Munkul]

I'm assuming you know it's all seated properly in the neck, tip adapter/tip etc.

Insulator inside the nozzle? If it's not right, it'll allow current transfer up in the brass neck... that'll cause arcing or heating and resultant friction...

EDIT: I'm being dumb and forgot how a MIG gun works. The nozzle insulator is just to keep the nozzle from conducting.

It does seem like some sort of stray arcing somehow though...

 

[Munkul]

What if the neck internal liner is worn? It would allow current transfer from the wire to the neck through the brass liner, and therefore to the nozzle also (I assume it's a push on style like binzel 501 arrangement) and therefore if you touch the nozzle to the work, it will transfer current and heat up.

I assume there is some form of insulation between the neck internals and the brass liner, otherwise you would always have this issue.

 

[Hood]

Everything regarding liner, gas lens, tip adapter etc is good as they have all been replaced and the brass liner especially as I have gone through about 10 of them.

Definitely not touching the work with the shroud and not sure if the actual neck is insulated but don't think it is.

I am going to try the old Binzel push/pull and see if that makes any difference but the problem is it seems to work away fine, sometimes for hours then when it happens it can do so quite consistently. For example I probably only did 30 mins total welding today and it happened 4 times, thankfully only once did I destroy a brass liner.

 

[Munkul]

Sorry I can't help then

Have you tried the binzel neck on the ewm gun?

Its the most frustrating sort of issue I know. When push-pulls work properly they're unbeatable. We bought a watercooled Lorch pushpull before christmas, and it's an absolute weapon. But at some point it will break, the lads will ask me to sort it and I will hate life!

 

[Hood]

Yes, it is actually the Binzel neck I am using at the moment, I think the reason for that is it was happening with the EWM neck and I was trying to eliminate the neck but could be wrong as it was a while ago, I may have swapped for another reason. I will get the meter on the various necks I have and see if they are insulated or not but I don't think they are.

 

[Brad93]

It's probably the neck of the torch, i've got an otherwise working lorch gun which anytime you've welded more than two beads the feed goes to absolute crap.
New torch solved the problem.

apparently you can buy new necks but changing them looks like a right pita

 

[Hood]

Hopefully that is all it is, torch itself is over £3k and if it is the welder then I am packing it in

 

[Brad93]

Hopefully that is all it is, torch itself is over £3k and if it is the welder then I am packing it in

I know the feeling mate

 

[Hood]

Got a chance to test continuity on all of the necks I have and all are the same, inner tube to outer of the neck there was no continuity so all looks good on that front. All have the tube where the brass spiral fits as connected direct to the power so..
I am not sure when I will get a chance to try the welder again as I am quite busy but I think the old Binzel push pull is likely the best thing to try initially, if it happens with that then it looks like it is the welder, hopefully not though.

 

[Hood]

Put one of the EWM necks on with new tip adapter and contact tip, seemed to go ok for a while and then did the melt thing. Hauled out the Teflon liner and put a new one in and tried again, melted the wire after 20mm weld, tried again and same again.
Hauled off the EWM push pull, set parameters so that the Binzel push pull would work and tried the Binzel, seemed to go fine and did feel different but only time will tell as it can work great for a fair bit of welding then start screwing up so...

 

[Hood]

Just to update on this, still not sure exactly what the problem is but I do now know it is the EWM torch. I have just finished up a job with quite a lot of welding and at first I had the EWM torch on. It went ok for most of the first day but then it started melting the wire again. Swapped over to the old Binzel torch, bit of a pain as I only have control of wire feed with it so if I want to swap to double pulse I have to go back to the wire feed unit. Anyway the Binzel has not melted the wire once in the last 9 days of welding so I know for sure it is the EWM torch.
I tried different necks, different contact tips, even swapped out the tip adapter and several neck liners but it still happened. Whether it is something to do with the torch itself (physical) or the electronic control part of the torch I do not know, it may even be the welder itself not working right with the electronic adjustment at the torch.

Next step I am going to dismantle the torch and see if I can find a problem, if not then I may haul out the wiring and control board and make up a makeshift housing and mount it some way to the Binzel to see if the binzel works with the electronic control attached, doing so will let me know whether it is the torch or electronics that is the problem. If it still happens then I will still not be sure whether it is the torch wiring/circuit board or the electronic interface in the welder but one thing I know is I don't have a spare £4k for a new torch

 

[Bullet2012]

£4k for a new torch

Should have bought one in January, they were a grand cheaper then.

 

[eddie49]

The brass block into which the swan neck screws is supplied with power by a heavy copper cable that runs inside the torch umbilical. This cable may end with a lug that is bolted to the block, or it may be coaxial and surround the liner. Perhaps that cable is broken, and power is being supplied to the MIG tip via the liner.

 

[Hood]

The brass block into which the swan neck screws is supplied with power by a heavy copper cable that runs inside the torch umbilical. This cable may end with a lug that is bolted to the block, or it may be coaxial and surround the liner. Perhaps that cable is broken, and power is being supplied to the MIG tip via the liner.

I will have to have a look but the cable broken can not be the cause if I am understanding what you are meaning. The reason being the liner is teflon so the power has to be at least getting as far as the torch itself. There may be a loose connection some place at the torch which hopefully is the case as something simple like that would make my day.

 

[Hood]

Should have bought one in January, they were a grand cheaper then.

It was £3k when I bought it 5 years ago, they are now £3.8K plus VAT.

 

[Hood]

The brass block into which the swan neck screws is supplied with power by a heavy copper cable that runs inside the torch umbilical. This cable may end with a lug that is bolted to the block, or it may be coaxial and surround the liner. Perhaps that cable is broken, and power is being supplied to the MIG tip via the liner.

Hopefully I have found the issue and it was along the lines of what you were thinking.
It was not the cable but this.

The part the neck screws onto was loose and you can clearly see where it has been arcing.

I have cleaned it up with emery cloth and put it back together and fingers crossed that will be it working as intended.

 

[Robotstar5]

I'd probably replace a couple a year at work where the Euroconnector locking ring had come loose.

 

[Munkul]

Hopefully I have found the issue and it was along the lines of what you were thinking.
It was not the cable but this.

That certainly looks like it could be the problem!