Help with a miller welder problem...

[Wicked_S10]

Okay, I appologize if this is the wrong forum, but I need some help here, because I think my welder has gone to hell (millermatic 251). First off, I have been useing it for production for about 9 months with no trouble, so I am fairly sure it is not my ability that has gone to hell, but I am open to advice :) Anyhow, while welding with it, when the puddle gets very hot the welder will start to pulse, the feed is staying steady according to a buddy who watched the wire feeding in while I did it. The wire is either burning back into the gun and the feeding again causeing the pulse effect, or the wire begins feeding to fast and cannot burn properly, I am unsure which. When I explained things to my friendly neighborhood airgass last week, they told me, new liner and it will be good. I swapped the linner and it was a bit better, but not much. I have put 5 different elctorde/tips in it with the same results. The odd thing is, it started this right after I put a new tip in it about 1.25 45lb spools of wire ago and has some days where it is worse and somedays where it is okay. On bad days it will weld about an inch or so before it starts feeding poorly. When it is not doing it so bad, I can compensate for it by adjusting the distance from the gun to the work piece when it starts pulsing, kind of following the pace of the pulsing feed, but this is a royal PIA. When it is bad, nothing I do will make it weld right, but if I stop and start again, I can get another inch or so out of it before it starts up again. My feed rates and voltage have not changed, but I have expierimented with higher and lower feed rates and voltages trying to get it to smooth out, but had no luck. I have also purchased a brand new lot of miller brand elctrodes, cleaned my feed rollers and am still haveing trouble, Do any of you have any ideas?

Thanks,
Jason

[blown4x4]

I would also like to know as well. I have a welder that is doing the same thing. Its a real PITA!

[donkeystompit]

This may not help but mine was doing the same. Its a hobart 175. I am using .30 wire. The tip looked to be fine. I was using a .30 tip. Well, I had some .35 tips laying there so I tried them. That welder has never worked better.

[Wicked_S10]

This may not help but mine was doing the same. Its a hobart 175. I am using .30 wire. The tip looked to be fine. I was using a .30 tip. Well, I had some .35 tips laying there so I tried them. That welder has never worked better.

It sounds like your trouble was that the drive rollers were to tight, if the wire gets squished, it will still go through the liner okay, but not the tip. I run .035 wire, the next larger electrode is .045 if I am not mistaken, this is probably to large to work well. I am at my wits end about this thing, I have cleaned or replaced nearly every normal wear part on this machine. For a $2000 welder I am getting fairly frustrated. It is right at 3 years, or just past 3 years old, which may or may not make it out of warranty. I have several other miller machines and not one problem ever. I am going to look into my line voltage next with a logging multi meter, see if I am experienceing voltage fluxuations while welding... I cannot think of anything else that might be giving me this trouble.

Later,
Jason

[mj]

started when you chanded the tip? change the tip again

[Wicked_S10]

5 different tips have been on it since it started this. The latest thing I tried was purchaseing a new package of electrodes miller brand and of a different lot than the ones I had. Same trouble. I actualy changed wire spools and tip when this all started. I originaly thought I had a piss poor spool of wire, but I am bout 11 lbs through the new 45lbs spool, and if anything it has gotten worse. Maybe I will check for lot numbers on the tags of the spools, if I got some bad alloy and two spools of the same lot, that might be causeing the trouble...

Later,
Jason

[WA-HCRC]

i bet if you upgrade your whole gun/line setup to a quality tweeco setup your problems will dissapear, unless its a drive problem.

[wheelin66bronco]

I had the same issue with my hobart handler 180. Ended up being the liner and had the wire feed tightened too tight. I also added a wire cleaner right at the feed that helped a bunch.

[Wicked_S10]

i bet if you upgrade your whole gun/line setup to a quality tweeco setup your problems will dissapear, unless its a drive problem.

So you really think the problem is down stream of the actual welder. I am about a 1/2 inch from sending the whole thing in to miller to be looked at, but my business cannot really afford to be without my welder for so long. I am game for anything, a new gun setup is probably going to be expensive, but I will probably appreciate it regardless of if it fixes the problem or not. I was kind of expecting to hear that it is a power supply problem with the welder. I guess I dont understand what else could go wrong/wear out with the gun other than the normal consumables.

As for the wire cleaner, was that something you built, or is it available comercialy?

Later,
Jason

[Mudplugga]

At one of the fab plants I worked at years ago the welders ran the wire through a small bit of cardboard, just pushed it through, before the pinch rollers. This seemed to keep most of the crap out of the rollers.

Most MIG problems start at the rollers or the liner.

Mudplugga

[wheelin66bronco]

This is the cleaner/lub pads I am talking about.


http://www.welders-direct.com/merchant2/merchant.mv?Screen=PROD&Store_Code=WD&Product_Code=WLD00706X

[BlueTorch]

I did not read through all the posts but I will bet you I know the problem. After a while the liner in the lead needs to be replaced. It is the bike brake cable looking thing that rund down the center of the torch lead. It is easy to replace and should be replaced all along. A few things can happen to it. One you coil the cable too tight causing it to bend. Two someone drops something heavy on it causing it to bend. Three, metal shavings get inside it and cause trouble. When you hit the trigger it creates a magnet of sorts. You can watch metal shaving freaking out on the ground around it. Also running rusted wire through it can case it to surge. It gets trash in there. The last thing is they do wear out from running wire through the machine.

Not that I have welded enough to know LOL :p ... but I am willing to bet that this could help you out. Let me know if you have any questions.

Thanks
Dan

[ranger]

I've had this happen and was casued by different things. Tips, liner, had a small piece of wire inside the liner, feed rollers to tight, feed rollers bearings full of metal shavings, and welding wire that was not fresh.
Had a bad spool of wire to, about drove me crazy trying to figure out what was wrong with my machine, to make a episode short I swapped the spool and all was good.......

[kwrangln]

Put a new liner in it and ignore the recommended liner length on the liner box. Cut the liner so that at least 1" sticks out of the gun and then press it into the gun when you install the tip adapter. If the adapter wont seat all the way, then trim the liner back a fuzz and retry it, repeat as necessary to get the adapter seated all the way. Cutting it at the recommended 1/2" or less, will leave a gap between the liner and tip which will allow the wire to bend between the two adding friction which will make feed unsteady.

[WA-HCRC]

So you really think the problem is down stream of the actual welder. I am about a 1/2 inch from sending the whole thing in to miller to be looked at, but my business cannot really afford to be without my welder for so long. I am game for anything, a new gun setup is probably going to be expensive, but I will probably appreciate it regardless of if it fixes the problem or not. I was kind of expecting to hear that it is a power supply problem with the welder. I guess I dont understand what else could go wrong/wear out with the gun other than the normal consumables.

As for the wire cleaner, was that something you built, or is it available comercialy?

Later,
Jason

IIRC a Quality tweeco is around 225-250, but they handle some much better than a factory miller gun/lead.

[Wicked_S10]

I did not read through all the posts but I will bet you I know the problem. After a while the liner in the lead needs to be replaced. It is the bike brake cable looking thing that rund down the center of the torch lead. It is easy to replace and should be replaced all along...

I put a new liner in it a week ago, .035-.045 size instead of the stock .025-.035 one. The liner helped a bit, but overall not much. The thing that is really hard to explain is it only does this sporaticly. It will sometimes weld for a few minutes with no trouble and sometimes for hours. I did however follow the instructions with the liner and cut it to the recomended stick out length, I even measured. The problem seems to get worse the hotter the machine gets, or the longer the weld. The 251 has fan on demand, and I really have to get it running hard to kick the fan on, but fan on or off, does not seem to make a whole lot of difference, so I am guessing it is not overheating. Maybe it is possible I got a bad liner straight from miller, and I cna try another one, but if a new gun is only $200 and change, I think that might be my best try. I am going to rob the gun from my buddies .5 year old 251 tomorrow and see if it does any better, if it does it defenitely narrows down my problem.

Thanks for all of the advice so far, I am defanitely going to try the wire cleaner, but probably just a home made cardboard one for now. As for the wire being bad, like I said, I am on my second spool and the same trouble. I am going to hit the shop right now and look the old spool so I can look for lot numbers. If they are the same lot, I am going to go get a 5lb spool from the tractor store tomorrow and see if a different manufacturer/lot will be any better. Anyhow, thatnks for the input so far. Keep it comming!

Later,
Jason

[420willys]

it might be your drive motor, take the gun off but keep the trigger wire conections conected and try to hold back the wire, watch out the wire will be live. if its still under warrenty then give miller a call and see if they can send out a tech. you might not be the only persion with this problem and there might be a PI ( product improvment ) on the drive motor. it sounds like you are doing all the right things so it allmost has to be the welder.

the wire cleaners work great at keeping dust and grinding grit off the wire spools and the make a oil ( wire lube ) that go's on the cleaner and it wont contaminate your welds, i used it on all UT/X-ray weld's before and nothing showed up, jason.

[Moab Austin]

have you checked to see if your gun is loose where it gotes into machine?

on my welder (same one) there is somthing going on inside the lead right were it comes out of the welder..it started doing what you are saying more and more often..I noticed that it was to do with the position that the torch lead was in..

I ziptied it down to the base of machine so if cannot move..it takes some length off of it but it welds.

I need a new torch lead

[Wicked_S10]

The gun is tight where it goes into the welder and makes the physical connection. I have not noticed this to be a positional thing with the lead itself, but that is defenitely a possibility. I will try experimenting with it more today, and once I have my buddies gun here that will pretty much narrow it down if it is fine. Thanks again for all of the help so far.

Later,
Jason

[bluesman2a]

I have a 251 and have gotten GREAT service from the guys over at the Hobart board (they are same company). Check out their board, they generally have pro welders and factory reps lurking there, betcha they can help you out, when I had problems they shipped me replacement parts based on my discussions on the board.

http://www.hobartwelders.com/mboard

If I were to guess at the problem I would look at:
1) feed rollers and brass feed thingy (are yours worn or too tight?)
2) liner
3) try smaller 2# roll of a smaller wire (30 or 23) and see if you have the same problem, I know it's not what you use in production, but it would be a good test.

[Wicked_S10]

Okay, today I have Put my buddies gun on it, same thing. I took a torch cleaner to one of my new .035 tips and opened it up a little bit and it made no noticeable improvement. I took the spool off and found the spool arbor to be very tight, even with the adjusting nut backed way off. I pulled the whole assembly off and found a bunch of metal dust between the arbor and clutch washer. I sanded out the grooves in both pieces, put a thin layer of grease in there and reassembled. The welder no longer makes noises while feeding, and seems to feed a bit smoother, but it still is not right. i built a homemade wire cleaner from pieces of leather sandwiched between pieces of cardboard. Not much better, but perhaps a small amount. The drive rollers do nto appear to be worn at all, but they had some surface rust on them and I cleaned them thouroghly with a wire brush. I have adjusted them numerous times, both according to instructions, and to the settings that I have always run with no difference. I turned the rollers around for the .030 setting and ran them on the .035 wire, not very tight, just to see if the rollers were slipping, no change. I am really leaning toward it being something in the power supply. I will check out the hobart board, see if I can get some help there, but keep the discussion going here, these tips may end up helping someone...

Thanks,
Jason

[Easy Rick]

Just a thought, but you may consider checking your ground cable crimps at both ends. Could it be an intermittent ground loss when the cable gets hot?

Good luck,
Easy Rick.

[Wicked_S10]

I was just looking at that after I posted the last message. The crimp on the clamp end of the cable shows some corrosion, and I am going to take it apart and clean it well. Also the clamp end of the cable gets very hot but the rest of teh cable does not, this could also be a sign of a poor ground. I am waiting for it to cool to take it apart. I guess worst come to worst, i am going to damn near have a new welder by the time i am done cleaning, repairing and replaceing shit :D

Later,
Jason

[Wicked_S10]

Well, my ground clamp was in terrible shape. I took it apart and cleaned it thouroughly, put it back together, and after a few welds it appears that the thing is working well now. I cannot believe that after all that I tried, it ended up being something incredibly simple. I had considered the ground being a problem before since i weld on a table, but even with the work piece grounded directly I still had the problems. This has defenitely been a lesson to me, I think that the clamp went bad because oi\f a thin layer of metal plasma dust that i never bothered to clean off the corner of my table where the machine grounded. It looks like the dust welded itself to the ground and the problem continued to get worse the more I removed the clamp and work on my buggy and then going back to the table. Thank you all for your help, it is very much appreciated.

[Creepy196]

Just a thought, but you may consider checking your ground cable crimps at both ends. Could it be an intermittent ground loss when the cable gets hot?

Good luck,
Easy Rick.

And Rick's the winner! Good call, and a lesson to check the simple stuff first! I'm still learning that one!!!

:beer:

[Bubba_Jeep]

I have limited experience with MIG, but experienced the same thing with my Lincoln 175. The problem appeared to be the roll of wire. It was near the end, and would not feed smoothly. No amount of fusing with roller tension or the wire brake would stop the erratic feed; a new spool of wire did.

[Halogrinder]

RUST ON THE WIRE



check w/ another spool of fresh wire. it happens a lot to the surface wires on my welder, cause of the humidity of the area im in

[merr6267]

It seems that you have it figured out . . . but I'll add to what you have experienced. I've got a Snap-on 212A and it was feeding very sporadically. It ended up being the relay that drives the motor. I don't know what the Miller uses, but there was a relay that's specifically for the roller motor and the contacts within the relay, (not the ones that plug into the welder, but inside the relay,) were corroded as heck. I took apart the relay and filed them down and put it back together and it has never fed so well before. I also bought a new relay for a spare when my file job goes bad.

Just something else you might want to check. Good luck.

Phill