Top X rod scoring, top two ball tracks, yet again.
I’m seeing localized scoring on the top X rod, specifically in line with the two top ball tracks. This matches the area of highest load from the forward-mounted extruder. This is after relatively low total usage and careful maintenance. There is absolutely no sign of bearing wear: no noise, no rough motion, and no gray or contaminated grease at all (the grease remains clear).
This is second time it happens. The first time, I got the rod replaced under warranty. When I installed the replacement rod, I made sure not to tighten the zip ties too much. So it took a while for the problem to resurface, and I suspected the problem was solved, but here we are yet again.
Rotating the rod ~45° so the LM8UU ball tracks no longer ride on the scored area immediately restored smooth motion. Given the load geometry of the MK3S+, this appears to be a localized, load-driven wear pattern rather than a lubrication or bearing issue. At this point I’m monitoring rather than replacing, as performance is unaffected, and I think I will be purchasing a different printer in the near future anyway.
Still, I am open to hear from others with the same experience, or advice. Thanks!