Bent threaded rod

One of the rods of my TAZ 2.1 arrived slightly bent. I cannot detect any issues save a wobbly and an annoying humm when moving the Z axis rapidly. During normal operation, I cannot detect any issues – no change in leveling, no vibration, etc.

Is this something that I should still have replaced? Or should I leave well enough alone?

The plastic Z nut spring is designed to accomodate any deflection in the threaded rods. As long as your bearing rods are straight the motion on the Z axis will conform to that bearing unless the threaded rod is way off. That being said, your threaded rod may not actually be bemt, just misalligned. check it with a straightedge. If it is bent, remove it and straighten it. it can minorly affect print quality in regards to how your layers allign over one another.

If you are concerned about the threaded rod we’d be happy to take a look at it. I would recommend taking a photograph if possible, from right above the threaded rod looking as straight down the threaded rod shaft as you can manage. A little bit of play on the free end is acceptable as the Z axis nuts on the X axis ends are isolated. One big debate in the RepRap 3D printing world, is whether constrained Z axis threaded rods help or hinder printer operation and quality. An obvious bend in the threaded rod is not something that should normally happen though. Once you get some photographs, please send them to Support@LulzBot.com with your order information and anything thing else you may have questions on.

Thanks!

Claudio