I'm about to start building a CoreXY style printer and can't decide which bearings/bushings to buy. My first printer was a Delta with belts and opendbuilds wheels, so I'm lost regarding this matter.
Anyone tried these self-lubricating graphite bushings? How do they perform compared to the standard LMUU bearings?
Bushings will be quieter than linear ball bearings. Some online discussions complain of the linear bearings becoming noisy, and (in what I think is a failure of the balls to circulate properly) for the balls to develop flat spots. If the balls aren't moving properly, you will end up with a bushing. You might start with a bushing in the first place.
Bushings spread the load over the surface of the rods, so there should be minimal wear. Bearings and bushings are limited by the load and the speed. In 3D printers, neither the speeds or the loads are particularly high. Bushings should work well.
Bushings may have slightly higher sliding friction, which could result in slower maximum printing speed for motors with the same torque. The characteristics should be more stable as they age.
Others may have different experience, but I would consider either the self-lubricated brass bushings, or perhaps the self-lubricated graphite bushings.
As an example, inkjet and laser printers do not use ball bearings for the carrier. 15 years ago, it was bronze bushing on stainless steel shafts. Over time, it has evolved to PTFE pads sliding on stamped sheet metal.
