Causes of Poor Wire Feeding with ER70S-6 Welding Wire

What are the most common symptoms of poor wire feeding?

Poor wire feeding often manifests as:
   - **Erratic Arc:** The arc becomes unstable, sputtering, or extinguishing frequently.
   - **Bird-Nesting:** The wire tangles or bunches up at the drive rollers.
   - **Burn-Back:** The wire melts back and fuses to the contact tip.
   - **Wire Sticking/Stuttering:** The wire doesn't feed smoothly, causing an inconsistent weld bead.
   - **Excessive Spatter:** An unstable arc often leads to more spatter.

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What are the main culprits behind ER70S-6 wire feeding issues?

Wire feeding problems can generally be traced back to issues with the **wire itself, the drive system, the gun and liner, or the contact tip.**

1. Drive Roller Issues

The drive rollers are responsible for pushing the wire consistently from the spool to the gun.
   - **Incorrect Roller Type:** For ER70S-6 (solid wire), you need **V-groove drive rollers**. U-groove rollers are for soft wires like aluminum, and knurled rollers are for flux-cored wire. Using the wrong type can deform the wire or provide insufficient grip.
   - **Incorrect Roller Size:** The grooves on the rollers must match the diameter of your ER70S-6 wire (e.g., 0.035" rollers for 0.035" wire). If too large, they won't grip; if too small, they'll deform the wire.
   - **Insufficient Drive Roller Tension:** If the tension is too low, the rollers will slip, causing inconsistent feeding or bird-nesting. Increase tension gradually until feeding is smooth.
   - **Excessive Drive Roller Tension:** Too much tension can crush or deform the wire, leading to feeding issues in the liner or contact tip, and potentially bird-nesting.
   - **Worn or Dirty Rollers:** Over time, roller grooves can wear down or become clogged with wire residue, reducing their grip. Clean or replace them as needed.

2. Liner Problems (MIG Gun Cable)

The liner guides the wire from the wire feeder through the gun cable to the contact tip.
   - **Incorrect Liner Size:** The liner's internal diameter must match your wire size. An oversized liner can cause the wire to wander and jam; an undersized liner will create excessive friction.
   - **Kinked or Damaged Liner:** A kink or severe bend in the gun cable or a damaged liner creates resistance, leading to erratic feeding or bird-nesting. Straighten the cable or replace the liner.
   - **Dirty or Obstructed Liner:** Over time, spatter, dust, or metal shavings can accumulate inside the liner, increasing friction. Blow out the liner with compressed air or replace it.
   - **Liner Too Short/Long:** An improperly trimmed liner can cause feeding issues at either end (feeder or contact tip).

3. Contact Tip Issues

The contact tip transfers the electrical current to the wire.
   - **Worn Contact Tip:** Contact tips wear over time, enlarging the hole and reducing good electrical contact, leading to arc instability and burn-back. Replace worn tips regularly.
   - **Incorrect Contact Tip Size:** The contact tip opening must match the wire diameter. An oversized tip will result in poor electrical contact; an undersized tip will restrict wire flow and cause burn-back.
   - **Spatter in Tip:** Spatter can accumulate inside the tip, narrowing the opening and causing resistance or blockages.
   - **Tip Loose in Diffuser:** A loose tip can lead to poor electrical conductivity and an unstable arc.

4. Spool and Tension Issues

How the wire comes off the spool is also critical.
   - **Incorrect Spool Tension:** The spool tension brake should apply just enough drag to prevent the spool from free-wheeling and tangling when the wire feed stops. Too much tension makes the drive rollers work harder and can cause slippage; too little can lead to wire unspooling and tangles (bird-nesting at the spool).
   - **Poorly Wound Wire Spool:** While less common with quality ER70S-6 wire, sometimes factory winding can have overlaps or tangles, causing snagging.
   - **Rust on Wire:** Rust on the wire surface can increase friction and cause feeding issues, as well as lead to porosity in the weld. Store wire in a dry environment.

5. Other Machine/Setup Issues

- **Gun Cable Length/Angle:** An overly long gun cable or excessively sharp bends can increase resistance for the wire.
   - **Incorrect Polarity:** While ER70S-6 is typically DC+ (DCEP), incorrect polarity can lead to poor arc stability and feeding problems.
   - **Low Power/Amperage:** Insufficient power can cause the wire to "stub" or "short," leading to erratic feeding attempts by the machine.
   - **Dirty Power Source:** Dust and debris in the wire feeder compartment can affect mechanical components.

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What's the best way to troubleshoot ER70S-6 wire feeding problems?

Follow a systematic approach:
   1. **Check the Basics:** Is the correct wire loaded? Is the gas on (if using gas-shielded ER70S-6)?
   2. **Inspect the Contact Tip:** Look for wear, spatter, or incorrect size.
   3. **Check Drive Rollers:** Verify correct type (V-groove), size, and tension. Clean them.
   4. **Inspect the Liner:** Disconnect from the feeder and gun, blow out with compressed air. Look for kinks or damage. Verify correct size.
   5. **Adjust Spool Tension:** Fine-tune until there's just enough drag to prevent free-wheeling.
   6. **Check Gun Cable:** Ensure it's as straight as possible during operation.
   7. **Verify Amperage/Voltage Settings:** Ensure they are appropriate for the wire diameter and material thickness.
   By systematically checking each potential point of failure, you can usually identify and resolve ER70S-6 wire feeding issues, restoring smooth and efficient welding.