Need help... mig problems

[ace4059]

My PM 215 is having problems, they started about 2 months ago then got better, now they are back and I am having many problems where I cant even use my machine.

Problem 1: First off whenI turn on the machine and pull the trigger, it does not work sometimes. I pull trigger mulitple times and eventualy it will start working. IT only does this when I turn the machine on first thing in the day when the machine is "cold". After I use it (weld with it)turn it off , then turn it on later during the daythe trigger works with out problems, no matter how long it was off or on. ( so what I am saying is the trigger issue only happens once per day).

Problem 2: When I first strike an arc the wire burn back inside the tip. No matter how low the voltage or how high it is set on the wire burn off inside the tip when I first start to weld 90% of the time. I have adjusted the wire speeds high and low settings and it still happens.

Problem 3: Then when I finally establish and arc, I am welding along, maybe 1 inch, 3inches, or one foot, and all of a sudden the wire burns back into the tip. I used 1 tip the entire last year in 2006, Now in the last 2 months I has ruined over 25 tips.

Problem 4: Tonight all my welds were poris. I set the gas at 25-35 CFH and played with it and still no go. Gun tip was clean not clogged. gas WAS comming out from nozzle. No drafts, 75/25 gas. I would be welding along and all of a sudden the weld would get many holes i it, sometimes it was at the begining sometimes in the middle of the weld or at the end. My metal was clean. Looks like I forgot to turn on the gas, but was was on and flowing (I could hear it and feel it). Bottle is what I have been using the last 10 months. It has 1200psi left in it.


Here is what I have done to try to fix my welders issues:
Wire burn back: I have roller set loose not to crimp wire. (when you put hand in front of wire the rollers spin but no birds nest). Next I tightened up my rollers, but not to tight. I thought my wire was slipping thats why the burn back. I made sure the cords are straight with NO kinks. Wire tentision is set loose for the roll. I changed tips several times. I have adjusted voltage and wire speed to many many many different settings and does not help. I have tried different wire. (lincoln superarc 56). I tried a an 035 tip for 030 wire, with no luck. This is very aggervating.It acks like at the start and somewhere throught out the weld it get a very large spike in current and burns off the wire. Where is what I though, I though the wire was just hanging up and it would burn off, but when I feed it out for minutes at a time, there is no sliping or stops in the wire feeding.


Any other suggestions? Right now I need to just get it to weld and I can full with the porisity later.

[ace4059]

Also, I am not holding the mig gun too close to the surface. I am holding it 1/2" away. I tried upto 1-1/2" away but still have burnback. And my wire speed is set fast enough (I also tried all sorts of wire seed settings). BTW, when I finish welding and let off the trigger, the wire also burns back then.

[hankj]

Burnback issues are nearly 100% wire feed problems. From your description of the method you use to set feed roller tension, I'd say your tension is too loose.

As for the failure of the machine to feed wire/weld when you pull the trigger for the first time, unless you hear the contactor click when you pull (which I doubt), I'd say your trigger needs to be replaced, or there is a connection problem in the trigger leads at the gun end. Disassemble the gun and check out what's goin' on in there.

Hank

[ace4059]

Burnback issues are nearly 100% wire feed problems. From your description of the method you use to set feed roller tension, I'd say your tension is too loose.
Hank

When this first started happening, I did crank down the tension, it did NOT help. My LWS said do not crank down the tension because it crimps the wire and will cause even more problems.

[hankj]

Are you running flux-core? If so, then your LWS told you right,

Solid wire just ain't gonna squeeze into an oval.

Still, you say increasing the tension had no beneficial effect. At this point, I'd suspect the liner. Wire feeders are pretty basic. There's not a lot that can go wrong with the feed system. Spool tension, feed roller tension, gun liner, and tip are the only components to deal with!

Hank

[ace4059]

Solid wire just ain't gonna squeeze into an oval.

Still, you say increasing the tension had no beneficial effect. At this point, I'd suspect the liner. Wire feeders are pretty basic. There's not a lot that can go wrong with the feed system. Spool tension, feed roller tension, gun liner, and tip are the only components to deal with!

Hank

But solid wire can get hair line cracks and break off in the liner and ruin the liner (sounds crazy but yes it can happen.). I forgot the actual name of what that is called. I am going to clean the liner in the morning.

Am I just imaging thing or can the noltage really increase with a welder and cause burnback (even a small chance). If the liner dont work then Ill take it to LWS and see if they can fix it.

[hankj]

But solid wire can get hair line cracks and break off in the liner and ruin the liner (sounds crazy but yes it can happen.). I forgot the actual name of what that is called. I am going to clean the liner in the morning.

Am I just imaging thing or can the noltage really increase with a welder and cause burnback (even a small chance). If the liner dont work then Ill take it to LWS and see if they can fix it.

That's something I've never experienced. Never had a roll of solid wire "break" inside the liner.

As for the burnback issue, the only cause of burnback that I know of is a wire feed problem. There are instantaneous voltage variations all the time as arc length changes, but if the wire speed is fast enough to supply the needed wire, there's never a burnback.

Hank

[SundownIII]

Ace,

Many of the problems you describe do sound related to feeding issues. I assume you're using solid wire since you mentioned gas.

The voltage spikes you mentioned, lead me to believe there are other issues with the machine. Have you gone inside and checked for any loose connections or signs of arcing. The burnback you're encountering could be attributed to low voltage at the contact tip.

The fact that the gun feeds normally when not welding leads me to believe there's a problem with the machine not necessarily related to feeding. Have you checked the voltage at the contact tip?

Just my .02

[ace4059]

I am going to TRY to take it apart and see if any loose connection. I bought a New linear today so Ill see if that helps (I doubt it will since the wire feeds perfectly when not welding).

[ace4059]

I think I have it almost fixed. I changed the liner and that fixed about 80% of the burn back isses. It will still burnback everyonce in awhile but not as bad. It seems like I have less burnback with 035 wire (030 seems to be worse).

I found out what was causing the porsity. My contact tips were VERY large so the gas did not have room to flow between the contact tip and nozzle. The contact tip was sticking out 1/8" outside the nozzle. I grinded the contact tip off 1/2" and redrilled the hole so the wire would feed through. I then grinded some of the diamater off to make it smaller. It then worked perfectly.

Now all I have to figure out is why I still get some burn back. I still need to check the voltage. How Do I do that?

[imagineer]

This might be too simple a suggestion, but it might simply be a bad wire to the trigger.

Recently, I fired up my PM175, only to have the trigger seem to not work. Following standard trouble shooting protocol, I shook the cable, smacked the torch off the table a few times and triggered it 20 times or so...nothing, only a couple of sputters from the feed motor.

At the time, I was doing a welding favor for a friend who is an electrical contractor. He suggested that the "line cord" used for the trigger control may have broken inside the insulation, thus disabing the trigger. He explained that copper used in most line cord is a poorer, less flexible (cheaper) alloy because appliances using line cord are typically stationary and low amps.

After a few minutes feeling up the cord, sure enough, he found where the copper had broken. 10 minutes later, with a new cord installed, I was back to making sparks.

It could be possible that a bad wire is causing your wire feed to be interrupted sporadically.
Even a split second interruption could be cause for burnback.

[Dan]

With the wire guide installed, does the wire line up properly with the V groove in the lower drive roll?

You are feeding the wire off the top side of the spool , right?

You've tried different spool of wire if I 'm understanding correctly?

[Dan]

The burnback you're encountering could be attributed to low voltage at the contact tip.

To low of a voltage for the wire speed is going to cause the wire to stub, sputter or be poppy on arc starts. Too much voltage for the wire speed can potentially cause burn back.

[Dan]

If the unit has been sitting for a while, you might try cycling the wire speed dial back and forth.

My old CK 175 set around for quite some time without being used, and when I went to use it recently I was having some burn back issues with it. Checked everything out. Came to the conclusion the wire speed pot had collected some dust inside causing poor electrical contact. So I cycled the pot back and forth several times. After doing this, the unit has worked fine. Not sure this will fix your issue. I 'm just throwing something else out to consider.

[Sully2]

With the wire guide installed, does the wire line up properly with the V groove in the lower drive roll?

You are feeding the wire off the top side of the spool , right?

Do different machines feed from the spool differently???