Today’s guest post is by Ben Romenesko of Miller Electric.
Do wire feed troubles with your MIG welder ever leave you frustrated? Burn back, wire slipping, birdsnests... These are just a couple common problems customers call us about. The wire feed system is vital to successfully getting your MIG welder to perform.
Today I’ll walk you through the key components in the wire feed system so you know what to look for in each component.
The first place you’re going to want to look at is the source of your wire: the spool hub. The inner spring on your spool hub sets the brake tension on your spool of wire. The intent is to prevent the spool from over-spooling when the wire stops feeding, but there is a fine line between over-spooling and over-tensioning the spool. I like to optimize the brake tension by turning the wire feed speed to its max and then cycling the trigger with at least 6” of run out. The spool should coast so the first loop of wire just starts to loosen on the spool. A general factory setting is having the tension nut flush with the end of the threads, but each hub is slightly different. Be sure that when putting a spool in the machine the loose end of the wire is not fed through any of the other loops. This will cause feeding problems.
The second place to look for wire feed problems is the wire drive. There are two main adjustments at the wire drive; the drive roll groove and the drive roll tension. First, you’ll want to check to be sure the diameter of weld wire matches the drive roll groove you’re using. Be sure to use a knurled roll for flux core welding and a V-groove roll for steel. The knurled groove provides more traction on the softer flux cored wire so the drive doesn’t crush the wire. A knurled groove will provide more traction on solid wire, but it will also plug the gun liner much faster as well so we don’t recommend it on solid wire.
The other component of the wire drive is the drive roll tension. This is adjusted with the numbered tension knob seen in the picture. More tension is not always the best. Cranking down the tension all the way deforms the wire, causes shaving that plugs your gun liner, and allows the drive to birdsnest. Not enough tension will cause wire to slip in the drive rolls and result in inconsistent wire feed speed. Under the hood, it will look like the arc is pulsing. Here is a brief video that goes through the proper way to set your drive tension.
The final component of the system is the MIG gun. The first thing to check is that your gun is completely inserted in the drive casting and tightened down with the thumb nut. The next component to look at is the contact tip. The size of the tip printed on the side, needs to match your diameter of wire. As contact tips wear, that hole will start to become oblong. This will change how the current picks up through the tip and potentially cause weld performance issues. If the hole looks out of round, replace the tip.
If you’ve checked all of these things and you still see problems with wire feeding, it may be time to change your gun liner. There is a monocoil liner inside the MIG gun that guides the wire from the drive rolls to the contact tip. They can become kinked, plugged, or just wear out over time. As an initial step, compressed air can be used to try to clean out shavings that plug liners. This should be done on a routine basis to extend the life of your liner. Liners are a consumable of the MIG gun so they are relatively inexpensive if you need a new one. They turn out with a nut on the powerpin end. New liners need to be trimmed to length so you need to remove your contact tip when replacing a liner. Also note that it’s important to lay the gun out straight when replacing the liner so you cut it to the correct length. Here is a video that walks you through changing your liner.
Wire Feed Troubleshooting
|Wire won’t pass through torch||
|Drive roll slips on wire||
|Arc length is inconsistent||
|Burn back (pinned contact tip)||
|Wire feed starts slow||
About Today’s Guest Blogger
Ben Romenesko has been with Miller for over 5 years and his entire career has been spent with the Millermatic products. He originally came to the company as a mechanical engineer. He is currently a product manager at Miller’s Integrated MIG systems and oversees the Millermatic and ArcStation products.
Don’t Forget Miller’s Build with Blue Promotion!
The price for a Miller welder or plasma cutter has dropped, from March 1st to May 31st, with the latest Build with Blue promotion offered by Miller Electric. Welders will be able to take an additional 5-15% off the already discounted price of Miller welders and plasma cutters at the Baker’s Gas and Welding online store.
If you’re looking for a new welding machine or plasma cutter for your welding projects, these prices will be among the lowest for a Miller machine all year. In addition, if you need some new welding supplies such as a welding helmet, welding jacket, or welding table, you can use these purchases to get additional savings. Here’s how you can save money on a new Miller welder or plasma cutter.