Why is the Miller welder voltage dropping and increasing during weld?

Welding .375 thick material with .035 wire. Suggested voltage and wire speed is 19.0 and 310 by Miller. Lately during welding voltage will increase or decrease rapidly causing the welding process to snap crackle and pop. I have been welding for a few years and am aware of the settings and how metal heats and you must adjust as you go, but I have never had a problem like this. Does anyone know why this happens? Voltage will drop sometimes down to 16.0 which is a drastic drop in the middle of welding.

5 Answers

  • 1 decade ago
    Favorite Answer

    What is the rated current on your machine? Voltage should not drop so drastically during welding, unless you are close to the maximum rated current.

    Since you say this is a recent problem something else must be to blame. I agree with other posters- it sounds like a grounding issue, or else a loose, dirty or worn terminal somewhere in your machine.

    Additionally, In my experience, Voltage and WFS suggestions from ANY manufacturer or salesman should be taken with a grain of salt.

    Forgive me If I sound pedantic here. As a professional welder, it's your responsibility alone to select your tools and use them properly. After all one does not ask a car manufacturer how to drive, one does not ask a scalpel salesman how to do surgery. Only an incompetent surgeon would ever do so.

    On steels > 3/16" in thickness you really want to be using the spray transfer mode (provided you are welding in the flat or horizontal position.) *Conservative* spray settings for 3/8" would be 550-600 ipm and 30-36 volts. Though, you could easily go higher than that if you want to increase your productivity.

    The settings you quote are in the middle of "short-circuit transfer" range on the wire feed dial. This is FAR too cold. On 3/8" material you should expect to find lack-of fusion and lack of penetration defects in your welds when using short-circuit transfer.

    (You're welcome to do some bend tests to prove my point. Irregardless of the process used, good welds should *bend* through the heat-affected zone. They should NOT easily fracture at the root without bending first. If they do, your welds lack fusion and/or penetration.

    Does your welding machine provide at least 300 amps of output? If not, then it is probably not capable of producing acceptable spray transfer. If this is the case I would advise you to not MIG weld greater than 1/8" thickness for liability reasons.

    Finally there is a general rule of thumb to use: If you can hold the arc in one spot on the metal without risking burn-through, then your welds are probably too cold. Your welds would probably benefit from increased weld energy.

    Hope this helps. good luck.

    Source(s): Welder. Weld inspector.
  • 1 decade ago

    must be an earthing problem first check youve got a good earth (ie the cable and socket)the clamp grind the metal so no rust if that fails its the gun cable check at the cable inlet it is a simple problem somewhere it could even be a new tip or change the gun for another take it your welding flat at 19 volt and wirespeed 310 amps are you working to a procedure?i dont know the miller but ive been licoln welder 15 years is it argon shielded?if its argon shielded make sure your not putting too much gas in and not too little (ie perosity) make sure youve cleaned the area where being welded theese are all probs it can be tell, me more if you can?

    ps if its got a small wire running from the machine usually to a small crocodile clamp if thats not on the earth thats a main cause of whats happening

    pps every welder has to weld out of procedure now an then due to the calibration of the machine if its old you just have to adjust accordinly if more amps and volts are used it just gives a bigger heat affect zone and more penetration

    i hope i helped a little

  • 1 decade ago

    It is very strange to me that Miller would suggest wire feed speed and voltage for GMAW without knowing what zone you prefer to use (depending the thickness you are welding you can use short circuit transfer or spray transfer). 310"/min with 19 volts will definitely put you at the higher end of the short circuit transfer zone which on .375 material will not do much.

    Also 19 volts seem to be very low for arc voltage even for .035 wire at 310"min. That is why you have an erratic arc (not enough energy in the arc to keep it stable) which basically generates the voltage to vary a lot. Increase your voltage to 21-22V and see if your problems are still there.

    I definitely suggest to increase the wire diameter and use spray transfer mode for welding .375 material otherwise you may end up having insufficient penetration or insufficient fusion.

  • 1 decade ago

    I suggest that you contact your Miller rep, or try their website.

    Sounds to me like your welder is ailing.

    But I am a Chemical Engineer with next to no knowledge of welding, so take that with 64 mg NaCl [a grain of salt]

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  • 1 decade ago

    Very good reply Wombat.

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