WELDING TIPS COLUMN
Poor wire feeding is a common problem that can be a significant source of downtime and lost productivity — not to mention cost. Poor or erratic wire feeding can lead to premature failure of consumables, burnbacks, bird-nesting, and more. To simplify troubleshooting, it’s best to look for issues in the wire feeder first and then move toward the front of the gun to the consumables.
Finding the cause of the issue can sometimes be complicated. Fortunately, however, wire feeding problems often have simple solutions.
What’s Happening with the Feeder?
When poor wire feeding occurs, it can be related to several components in the wire feeder.
- If the drive rolls don’t move when you pull the trigger, check to see if the relay is broken. Contact your feeder manufacturer for help if you suspect this is the issue. A faulty control lead is another possible cause. You can test the control lead with a multimeter to determine if a new cable is needed.
- An incorrectly installed guide tube and/or the wrong wire guide diameter may be the culprit. The guide tube sits between the power pin and the drive rolls to keep the wire feeding smoothly from the drive rolls into the gun. Always use the proper size guide tube, adjust the guides as close to the drive rolls as possible, and eliminate any gaps in the wire path.
- Look for poor connections if your MIG gun has an adapter that connects the gun to the feeder. Check the adapter with a multimeter and replace it if it’s malfunctioning.
Take a Look at the Drive Rolls
Using the wrong size or style of welding drive rolls can cause poor wire feeding. Here are some tips to avoid problems.
- Always match drive roll size to wire diameter.
- Inspect drive rolls every time you put a new spool of wire on the wire feeder. Replace as necessary.
- Choose the style of drive roll based on the wire you’re using. For example, smooth welding drive rolls are good for welding with solid wire, whereas U-shaped ones are better for tubular wires — flux-cored or metal-cored.
- Set the proper drive roll tension so there’s sufficient pressure on the welding wire to feed it through smoothly.
Check the Liner
Several issues with the welding liner can lead to erratic wire feeding, as well as burnbacks, and bird-nesting.
- Be sure the liner is trimmed to the correct length. When you install and trim the liner, lay the gun flat, making certain the cable is straight. Using a liner gauge is helpful. There are also consumable systems available with liners that don’t require measuring. They lock and concentrically align between the contact tip and power pin without fasteners. These systems provide error-proof liner replacement to eliminate wire feeding problems.
- Using the wrong size welding liner for the welding wire often leads to wire feeding problems. Select a liner slightly larger than the wire’s diameter, as it allows the wire to feed smoothly. A liner that’s too narrow will be difficult to feed, resulting in wire breakage or bird-nesting.
- Debris buildup in the liner can impede wire feeding. It can result from using the wrong welding drive roll type, leading to wire shavings in the liner. Microarcing can also create small weld deposits inside the liner. Replace the welding liner when buildup results in erratic wire feeding. You can also blow compressed air through the cable to remove dirt and debris when you change over the liner.
Monitor for Contact Wear
Welding consumables are a small part of the MIG gun, but they can affect wire feeding — particularly the contact tip. To avoid problems:
- Visually inspect the contact tip for wear on a regular basis and replace as necessary. Look for signs of keyholing, which occurs when the bore in the contact tip becomes oblong over time due to the wire feeding through it. Also look for spatter buildup, as this can cause burnbacks and poor wire feeding.
- Consider increasing or decreasing the size of contact tip you’re using. Try going down one size first, which can help promote better control of the arc and better feeding.
Additional Thoughts (And a Final Tip)
Poor wire feeding can be frustrating, but doesn’t have to slow you down for long.
If you still experience problems after inspecting and making adjustments from the feeder forward, take a look at your MIG gun. It’s best to use the shortest cable possible that can get the job done. Shorter cables minimize coiling that could lead to wire feeding issues. Remember to keep the cable as straight as possible during welding, too. Combined with some solid troubleshooting skills, the right gun can keep you welding for longer.
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