A production facility is mass-producing welded components using GMAW. They are experiencing significant wire feeding issues, frequent burnbacks, and an erratic arc with their current ER70S-6 wire. The current shielding gas is 100% CO2. What is the most probable issue contributing to these problems?

Question: A production facility is mass-producing welded components using GMAW. They are experiencing significant wire feeding issues, frequent burnbacks, and an erratic arc with their current ER70S-6 wire. The current shielding gas is 100% CO2. What is the most probable issue contributing to these problems?

Answer options:

• The gas flow rate is set too low for the 100% CO2.
• The contact tip to work distance is too long, leading to excessive resistance.
• The drive rolls are incorrect or have insufficient tension. ✅ 100% CO2 gas is highly reactive and contributes to an unstable arc, especially with ER70S-6 wire.

Correct answer: 100% CO2 gas is highly reactive and contributes to an unstable arc, especially with ER70S-6 wire.

Explanation: 100% CO2 is a very 'cold' and reactive gas for GMAW, resulting in a harsher, less stable arc, and more spatter compared to argon-rich mixtures. While wire feeding issues can be related to drive rolls or contact tip to work distance, the given symptoms of 'erratic arc' and 'frequent burnbacks' alongside wire feeding problems strongly point to the inherent limitations and reactive nature of 100% CO2 for smooth GMAW operation with ER70S-6 wire, particularly when trying to achieve a stable arc. Argon-rich mixtures would significantly improve arc stability.