It is possible for the gantry to become twisted such that is not perpendicular to the long edges of the raised bed. This is usually caused by an obstruction on one side that stalls that side of the gantry and misaligns the system, or a loose belt on one side.
If a belt is loose, tighten according to these instructions.
If the belts are tight and the gantry is twisted, re-equalize and synchronize the gantry using instructions on the gantry page.
Preventative > reactive
Even if your belts are tight and the gantry moves across the bed fine, the gantry could still be twisted and causing unnecessary stress and wear to the components. It is recommended to equalize and synchronize the gantry twice a year to ensure that it stays perpendicular to the long edges of the raised bed, even if it is not noticeably twisted.
Over time, it is possible for the delrin leadscrew block to wear down. This can introduce play into the system that decreases z-axis precision.
Once per year
Inspect the delrin leadscrew block for signs of wear. You can do this by gently pushing and pulling up and down on the leadscrew to see if you can feel any looseness in the system. If you detect there to be a large amount of play, replace the leadscrew block as soon as possible.
The z-axis leadscrew will become dirty after being outside for a prolonged period of time. Excessive dirt and grime on the leadscrew can cause premature wear, a loss of precision, and missed steps if not addressed.
Every 6 months
Wipe the leadscrew clean with a damp rag or sponge. Applying a small amount of high quality synthetic lubricant to the leadscrew can help make motion through the delrin leadscrew block smoother and quieter. We recommend high quality synthetic lubricant such as that used for bicycle chains.