What are some causes of bird nesting other than drive roll tension?

Bird nesting typically refers to a situation where the welding wire becomes tangled, often creating a mess that can obstruct the feeding mechanism. Among the possible causes, a dirty or damaged liner plays a significant role because it can create friction and restrict the smooth movement of the wire, leading to jams and tangles. Additionally, if the contact tube is restricted, it can further prevent the wire from feeding properly, causing it to bind and fold over itself. Burn back, which occurs when the wire melts back into the contact tip, is another common issue that can lead to bird nesting because it can create an uneven feed and sudden stops.

These factors collectively impact the wire's ability to feed smoothly through the welding gun, directly contributing to instances of bird nesting. Thus, identifying and addressing issues related to the liner, contact tube, and burn back are crucial steps in preventing this problem during MIG welding.