Alternative belt path for CoreXY
Before going to bed, I had an idea of an alternative belt path, so that the belt is always on the smooth side of the rollers, which can eliminate the influence of the belt on the VFA when the toothed part runs on the smooth side of the roller, then the VFA will be more affected by the motor and poor frame rigidity. Someone may say that the belt becomes even longer, but for small printers up to 250 mm this is not a problem at all. I could not find similar solutions on the Internet, and I am wondering if this will work at all, there is no time to design a printer for this and test it. 4AWD can be used for large printers. What do you think?
RE: Alternative belt path for CoreXY
I don’t own a Core One so I’m not familiar with the printer’s design. Certainly, the toothed side of the belts should never rub against the smooth idlers, If Prusa designed it this way, for sure they did a lousy job.
Paramount rules of a Core XY printer : toothed side of the belts should interact only with the gears of the stepper and the XY joint. Smooth side of the belts make contact only with smooth idlers. Neither side of the belts should rub against a plastic part.
RE:
Interesting idea. How much longer would these belts be on a CORE One? I'm not convinced by the statement "but for small printers up to 250 mm this is not a problem at all". As I understand it, the belt/pulley meshing, the belt's length and tension and the frame's rigidity all interact to create resonances at certain speeds, leading to amplified belt ripple. So belt length apparently is not something you can vary without expecting some change in the resonance frequency. Belt length is a major difference between the CORE One and the MK4/S, and I've read that it's the extra belt length that may account for some of the increased VFAs between the two.
I'm also not convinced that running the belt teeth over a smooth pulley is as bad as one might think. I'm sure I've read of people who have changed the two smooth idlers that matter for toothed idlers, and haven't improved the VFAs. Admittedly a toothed idler is not the same as running the smooth side of the belt over a smooth idler, but I'm not convinced this is going to gain much, and may even make things worse with the longer belts.
RE: Alternative belt path for CoreXY
A serious and competent manufacturer wouldn't ever design a Corey XY where the toothed side of the belts runs against a smooth idler. Period.
RE: Alternative belt path for CoreXY
A serious and competent manufacturer wouldn't ever design a Corey XY where the toothed side of the belts runs against a smooth idler. Period.
Unfortunately that's pretty much everyone then.
Every MK series did, Bambu, Creality etc etc.
Many including myself have replaced the smooth idler with a toothed one and it made little to no difference. I am 100% positive it's not the root cause of the VFA's on the C1.