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  • MM250 Wire Feed Problems

    I have been having problems that make it almost impossible to get any welding done. I have taken the machine to my local Miller store, and they say there's nothing wrong. This thing struggles to feed the wire while welding. It sputters terribly most the time when trying to start a weld, and when it does get a bead going, the wire speed will slow down, stop speed up or some times burn back. I have replaced the entire gun and cable assembly, feed rolls, liners, tips, and wire. This problem has persisted for years and everything I do helps, but only for a few welds. I have the feed rolls very tight, but I don't have a problem with birds nesting. The wire just seem to like to weld itself to the contact tip, and then the feed rolls slip. When I am changing rolls of wire, I feed the wire through the liner by hand, until it comes out of the tip. It feeds smooth, with a little resistance as it goes around the bend in the gun, but nothing real bad. Can anyone help?

  • #2
    I know you have changed everything but I have to ask. Are you running the correct size tips & liner? What kind of wire are you using, flux core or bare? What size? What kind of rollers do you have v-groove, u-groove or v-knurled?
    MM250
    Trailblazer 250g
    22a feeder
    Lincoln ac/dc 225
    Victor O/A
    MM200 black face
    Whitney 30 ton hydraulic punch
    Lown 1/8x 36" power roller
    Arco roto-phase model M
    Vectrax 7x12 band saw
    Miller spectrum 875
    30a spoolgun w/wc-24
    Syncrowave 250
    RCCS-14

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    • #3
      I am using .035 wire and have tried all different size liners and tips. I found that a .035 liner instead of a .035-.045 help for a short while, now I'm back to a .035-.045. I tried a .030 tip and that helped for a little while, now I'm back to .035. I run bare steel wire and I always try to buy the highest quality available. I also run stainless steel wire and the problem is much worse, which is understandable. One time I switched brands of stainless wire when I was running out a spool of "what I had". I bought a roll of Crown wire and my problems magically went away, for a little while, then it was back to the same old problem. A fresh tip helps for about 15 seconds of welding, a new liner helps for about 2-3 minutes. Keeping the gun hose and cable straight helps immensely, but I've welded with beat up old machines where you could tie the cable in a knot and it would still weld great. I'm lost on this one.

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      • #4
        Oh yah, I forgot to add that I'm using V-Groove rolls.

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        • #5
          I figure you probably know or tried all this but perhaps not so I will suggest it. Make sure the spool spins freely but has enough tension to stop itself when you let go of the trigger, it does not take much tension. If that is fine then check to make sure that after you adjust it and weld a little it has not changed some how, maybe it tightens up after a few turns? not probable but could be. I would check these first, it really should not need to much tension on the rollers to feed .035 wire. Also maybe check that it is not dragging or possibly just dirty and causing the problem. Also be sure the wire is feeding off the roll from the right side of the spool, ie top or bottom, so that it lines up pretty well with the in side of the feeder. And lastly, be sure that you debur your liner so that it does not casue a nest in the liner itself, I worked with a guy who left a welder like this and it took a while to figure out that it had a burr, although that just caused the wire to seem as if it were moving slower than it should have. I dont think most welder repair places actually try to weld with the machine so they may not notice if its a feed problem. I could be wrong about this though. As I said not meaning to imply anything with this post but sometimes the simple things elude me pretty well so maybe this is the case. Good luck.

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          • #6
            Are your rolls lined up together and straight with the liner hole?
            And also is your wire roll tightening screw well adjusted.

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            • #7
              I feed the wire through the liner by hand, until it comes out of the tip.
              Watch TV Online

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              • #8
                Originally posted by crawler30 View Post
                I figure you probably know or tried all this but perhaps not so I will suggest it. Make sure the spool spins freely but has enough tension to stop itself when you let go of the trigger, it does not take much tension. If that is fine then check to make sure that after you adjust it and weld a little it has not changed some how, maybe it tightens up after a few turns? not probable but could be. I would check these first, it really should not need to much tension on the rollers to feed .035 wire. Also maybe check that it is not dragging or possibly just dirty and causing the problem. Also be sure the wire is feeding off the roll from the right side of the spool, ie top or bottom, so that it lines up pretty well with the in side of the feeder. And lastly, be sure that you debur your liner so that it does not casue a nest in the liner itself, I worked with a guy who left a welder like this and it took a while to figure out that it had a burr, although that just caused the wire to seem as if it were moving slower than it should have. I dont think most welder repair places actually try to weld with the machine so they may not notice if its a feed problem. I could be wrong about this though. As I said not meaning to imply anything with this post but sometimes the simple things elude me pretty well so maybe this is the case. Good luck.
                crawler, That's what I was thinking, Maybe it's tightening up on it's own after being adjusted !
                So it will run for a few seconds, then slow or stop altogether !

                ........Norm
                www.normsmobilewelding.blogspot.com

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                • #9
                  When the drive rolls are closed are they rubbing on the liner/gun or the guide in the back.
                  MM250
                  Trailblazer 250g
                  22a feeder
                  Lincoln ac/dc 225
                  Victor O/A
                  MM200 black face
                  Whitney 30 ton hydraulic punch
                  Lown 1/8x 36" power roller
                  Arco roto-phase model M
                  Vectrax 7x12 band saw
                  Miller spectrum 875
                  30a spoolgun w/wc-24
                  Syncrowave 250
                  RCCS-14

                  Comment


                  • #10
                    Hey everyone, thanks for all the ideas and advice. I keep thinking that it is something simple and that I'm over looking something, but I've played around with it for years and nothing seems be the definitive cure. As for the wire spool tension, I have checked it and honestly, I have the drive rolls so tight that they have a killer grip on the wire so much so that I can use my hand to try to stop the spool from spinning ( like a brake ), and it takes alot. Thats the real mystery, the wire is feeding strong at the rolls, they are lined up, nothing rubbing or interfering, and the wire feeds through the gun by hand, but as soon as I try to weld, or as I'm welding, it locks up in the tip and slips at the rolls. I know I must have the rolls way tighter than they should need to be, but and less tension and the wire will slip worse. The rolls are so tight that they actually squeal when the wire is jamming at the tip. I like the suggestion about the possibility of a burr on the liner. I will look into this. I guess i will just have to start fresh with a new liner and less roll tension and take another close look at everything.

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                    • #11
                      I had a 250x with digital meters that gave me big problems with burnback.
                      Ultimately, I disabled the HotStart, which solved my problems.
                      I'm not sure if your problem is the same, or if your machine even has a HotStart, but this is my hunch.

                      If you do a search, either generally or sift through my old, old posts, it should turn up. It is not a difficult procedure to disable it. I might have a schematic, but I no longer have the machine.

                      I feel your pain and you should consider this before wasting more energy and money and things you have already tried.

                      Good luck!

                      P.S. The burnback was WAY worse at low voltage settings. I think going to .045 helped considerably before I performed the mod.
                      Maxstar 200DX
                      Maxstar 300DX
                      Dynasty 200DX
                      Passport
                      Spectrum 701
                      LMSW-52 spot welder

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                      • #12
                        If, you have the drive cranked tight at the drive, then all your going to is take out the worm and plastic drive gear. Thats if the drive up and stops, If it's spinning then your wheels are worn out. If years ago you stuck 15' gun on the unit and kept the regular drive wheels, thats where you went wrong, and now you'll need a single knurled drive wheel with the tension loose.

                        Tightening the drive wheel to the max really does zip other than flatten the wire out to a point it can't get through the tip. Seems really basic common sense to me, but apparently not to the poster.

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                        • #13
                          just last month i had the same problems after changing everything as well and having sent it out to fix the brand new spool gun went in the garbage and i put the old one back on which weld like a charm

                          i was welding aluminium 0.35

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                          • #14
                            Another thing you may try is to borrow another gun from someone if you can and see if the problem persists, that would at least give you an idea if it is the gun or the feed system. If that is even a possibility for you anyway. Good luck.

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                            • #15
                              Thanks again for the input from everyone. I do have a 15 ft cable/hose assembly, but I couldn't imagine having a shorter one for the type of work I do.
                              I have heard of knurled drive rolls but never tried them. Are they common, and why when I have described my problems to the guys at several welding supply stores, they have not recommended them?. I thought they would just chew up the wire and make it that much harder to push through the liner. I'm willing to try anything at this point. Also, I wasn't aware that "U" type rolls were available. What sort of difference could be expected from U's as opposed to V's?
                              My machine is a 250x, but it doesn't have any of the advanced features, just the typical voltage knob and wire speed knob. ( No digital readout either ).

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