Welding can be a complex process and MIG welding has its share of challenges to overcome. But, with some experience and knowledge it’s easier to find solutions and get back to work. In this brief MIG welding troubleshooting guide we offer solid advice to help you deal with potential pitfalls quickly.
MIG Welding Problems and Solutions
The source of MIG welder problems can be poor gas shielding coverage, improper technique, poorly defined parameters, incorrect travel speeds and more. Like any human centric activity, there is always a risk of human error and it’s easy to make mistakes. Sloppy technique, incorrect parameters and equipment settings are an ever-present risk. When a weld defect is recognized, it’s important to fix the problem quickly.
MIG Welder Wire Feed Motor Problems
There are four main causes of wire feed problems:
- Poor quality wire.
- Bird nesting of the wire.
- Worn out or defective guns.
- The drive rolls are worn out.
If you have wire feed motor problems, the first thing to check is the wire quality. Wire can become rusty, and this can lead to oxidation issues during MIG welding. If you can see a section of corroded wire feed it through the gun until you reach a clean section. This problem can be mitigated with proper storage where the wire is not exposed to rain and moisture.
The drive rolls should be replaced on a regular basis, and this is obvious if the drive roll needs to be tightened more than usually. If the wire looks good, the problem is usually the liner or the drive rolls. Liner issues tend to be caused by kinking, dirt, and clogging issues.
If the wire delivery is poor, it’s probably time to replace the welding gun with a newer model. The copper wires in the gun degrade over time and they need to be checked regularly. The easiest way to tell if the welding gun is failing is that parts of the gun start to feel hotter than they used to be.
MIG Welder Stops Working
The most urgent demand for MIG welding troubleshooting solutions is when the welding machine is stuttering, or it stops working altogether. There are four things that may fix the problem quickly:
1. The Power Output
If the welding machine is not arcing, the most probable cause is a power output issue. The outlet should be 110V-120V and a lack of power can prevent the MIG welder from working as intended. Another possible cause is that sufficient power cannot reach the welding machine due to a power cord break or other problem.
2. Contamination and Clogging
If there is a lack of arc in the welding, the cause may be the consumable parts. If these are clogged, the welding will not work, and even smaller pieces of debris can cause problems. This can be avoided if the liners are cleaned regularly and if you restrict welding to clean surfaces.
3. Hot Electrode Connection Issues
If the electrode holder is hot, there can be connection issues. The connections should be tight and using the wrong size holder can prevent the arc.
4. The Tip is Worn Out
After excessive use, the welding tip may not spark correctly, and this is a sure sign that the welding tip needs to be changed. This should be a priority because a worn tip can cause a lot of welding problems.
The MIG welder can fail for a wide variety of reasons. To maintain efficiency and to ensure that the machine has a longer lifespan, it’s important to take care of the welder. Regularly cleaning, parts inspection and the maintenance of a constant and grounded power connection is essential.
Common MIG Welding Problems
Now we’ll explore some common MIG welding problems in a little more detail.
Porosity of a Weld
Porosity is a common MIG welding defect. It’s caused when gas is trapped in the work-piece. The cause is usually inadequate shielding gas coverage and there are few ways to deal with this problem. Check the flow meter or regulator to ensure that the gas flow is adequate. If this doesn’t fix the problem, check the welding gun and gas hoses for leaks and seal the welding area from drafts.
Proper shielding gas coverage can be promoted with a larger nozzle to fully shield the weld pool with gas, The nozzle must be kept clean and free from spatter and the manufacturers contact tip recommendations should be followed. Some other causes of porosity include an excessive welding gun angle, dirty base material, wet and/or contaminants gas cylinders and over extending the wire from the nozzle.
Burn Through Weld
Burn through occurs when the weld penetrates through the base material, and this is very common when thinner materials are welded. The most common cause is excessive heat which can be prevented by reducing the wire feed speed or voltage. It’s also helpful to increase the travel speed when MIG welding on materials that are prone to burn-through such as ⅛” thick aluminum.
Cracks in the Weld
Cracks are common MIG welder problems, but there are several possible causes, and they are easier to prevent than fix. Cracking occurs when the stresses of the weld are too great for the seam or base material. Stresses can be caused by shrinkage when the weld cools and hot cracking can occur if the weld temperature is above 1000º. Hot cracks can occur rapidly, and the cause is usually contamination or the spreading of a bead that’s too thin.
Cold cracking may not occur instantly, it’s hard to identify and it may be noticeable days or weeks after the welding has concluded. Cold cracking is caused by hydrogen diffusion when hydrogen collects around contamination’s and imperfections in the weld. Choosing the right base and filler can prevent cold cracking problems.
Fixing a crack is possible, the weld should be bored out and then redone. The materials should be clean and rust-free to prevent future cracking. If you’re welding thin base material, you can preheat it to make it malleable for welding.
Burn Back on Contact Tip
Burn back can occur when the welding gun arcs and burns back into the tip. The cause is usually an incorrect contact tip size or wire size. If the tip is much bigger than the selected wire, this is more likely to cause burn back. To prevent this problem, use a tip and wire that are the same size. Another possible cause is poor quality wire or contact tips.
Choosing good tools will prevent micro-arcing and conductivity issues that can have a huge impact on productivity and efficiency. Dirty base materials and worn or damaged liners can also cause burn back issues. Maintaining a clean workspace and using clean materials can prevent burn back on contact tips.
MIG welding always causes spatter, but excessive spatter can be prevented if you follow a few simple tips. First, the amperage and voltage should be checked because high amperage feeds the wire too quickly. If the voltage is too high or low, excessive spatter can occur and it’s important to fine-tune the equipment and make test welds.
A short wire stick-out is essential to prevent spatter when MIG welding. Select the right contact tip size and use clean liners to keep spatter to a minimum. Short arc and globular techniques cause more spatter and spray transfer is much cleaner. Spray transfer improves the arc stability, and this helps to keep the spatter under control.
Fusion Issues When Welding
If there is insufficient voltage supplied to the welding gun, there will not be enough heat to create the weld. The weld may look good, but it will lack strength if the amperage was low. Poor technique can cause a lack of fusion if the material edges are not aligned properly. The beads must be aligned correctly to create the strongest welds and the welding gun angle can play a huge part in this process.
Magnetic arc blow can cause poor fusion; the magnetic field around the metal is distorted and the arc current is the usual cause. Demagnetizing the metal and adjusting the return cable clamps to improve stability can help. Tools and surfaces should be cleaned to improve fusion, even traces of dirt, rust and oil can prevent the formation of a complete molecular weld.
Conclusion–MIG Welding Troubleshooting
This brief MIG welding troubleshooting guide should help you to consider a more systematic approach to welding and troubleshooting problems. When a new problem arises look at any variables that have been recently changed and the cause may become clear.
Changing the technique, materials and the accumulation of contaminants in the workplace can all be considered as potential problems that need to be solved. Learning to identify and fixing MIG welder problems is important to boost productivity and to maintain efficiency.