One of the most common troubleshooting calls with the GMAW process has to do with wire feeding problems. This problem disguises itself in many forms, from arc flaring to lack of penetration. Sometimes the effects of poor feeding are obvious and easily corrected, other times however it is not easy to spot and fix.
If you suspect that you are having problems associated with erratic feeding use go thru the list below before paying someone to help you. There are times where the motor or a control board is bad and needs to be fixed, but in most cases it is a settings issue.
Causes and remedies for erratic wire feeding:
- Dirty/clogged liner – the liner in your gun will overtime collect “junk” that gets passed thru it. This includes wire lube, dust, dirt, copper flake created by excessive drive roll tension, moisture and other things. This will dramatically increase the friction and restrict the wire.
Remedy: Change the liner
- Incorrect tip size – contact tips typically are large enough to accommodate the wire they are intended for plus an extra few hundredths of an inch. At times the tip may not be manufactured to spec or the welder incorrectly selects a smaller tip. A small ID can drastically reduce wire feed speed and cause the wire to fuse to the tip.
Remedy: Use correct contact tip
- Oversized wire – although not very common this can cause feeding issues. Mig wire is drawn down to size by a series of dies. As these dies wear out they need to be replaced. If they’re not the wire will have inconsistencies including improper size.
Remedy: Switch to a different wire (can use same brand but look for different manufacturing lot, or switch brands)
- Incorrect drive roll tension – Newer wire feeders will have a gage for selection proper tension; however, older models do not. It is possible to have too much or not enough tension. If tension is set too low then you will get wire slip at the rolls. This will manifest as arc flaring and erratic feed.
Remedy: If wire is slipping increase tension – however, check spool tension as well. The problem may be the spool tension is set to high. If wire is being crushed and deformed causing erratic feed as it struggles to pass thru the tip then decrease tension.
- Incorrect spool tension – The tension on the spool is important because if it is too low it will allow the spool of wire to keep spinning after the trigger is released. This causes unspooling which later leads to wire tangling. If it is too high then the drive system struggles to pull the wire and the wire slips.
Remedy: Use proper tension. To select proper tension do a trigger pull and stop. The spool should stop when the trigger is released. Keep lowering tension until the spool barely spins after trigger is released. This way you have the lowest tension possible without creating tangling issue.
- Gun loops/length – With mig guns up to 25 feet in length another problem is introduced. If we are welding close to the welding machine the gun cable will be looped around. This increases friction and makes feeding a challenge.
Remedy: When possible use shortest lead possible. Get read of small radius loops on the gun lead and try to make big arcs with it if you are welding close to the wire feeder. If necessary, increase drive roll tension to help push the wire. If using a metal-cored or flux-cored wire consider going to a larger size or switching to a solid wire.
Whether your issues are due to erratic feeding or other issues always make sure all your connections are tight, make sure you have a good ground, and especially.
Do you know of other things which can cause feeding problems?