RE: Wavy mystery, unacceptable quality
If you read the Gates catalog and/or design guide, they say the pulley profile is proprietary, and the belts won't work properly with any other pulleys than Gates pulleys. Most of the belt manufacturers say this! Still, Gates is a high-quality manufacturer and if they have a suitable pulley, it might be a good place to start.
Yesterday, I started making some preparations for checking the belt tension and replacing the rollers.I noticed that my Core One already has a belt from PowerGrip Gates installed!
If it were me, I'd make some effort to check the existing pulleys, plus the rest of the COREXY system. If you confirm the pulleys are concentric, there's likely something binding or a motor problem still undiscovered.
Then the pulleys and idlers would also have to be from Gates?????
Unless you really need to print showroom parts with glossy filaments I would just ignore the VFA's. I got obsessive over it a first but then I just choose to ignore them since 99% of the stuff I print is functional.
I agree! And I think I'll come to that conclusion at some point too.
RE: Wavy mystery, unacceptable quality
If you read the Gates catalog and/or design guide, they say the pulley profile is proprietary, and the belts won't work properly with any other pulleys than Gates pulleys. Most of the belt manufacturers say this! Still, Gates is a high-quality manufacturer and if they have a suitable pulley, it might be a good place to start.
Prusa uses original Gates belts, but to my knowledge they make their pulleys in-house. Be it because they claim to make them better, or because they can make them cheaper. I did come across a Prusa drawing for a "Prulley" somewhere (ouch, pun alert...), but can't find it now.
RE: Wavy mystery, unacceptable quality
Prusa uses original Gates belts, but to my knowledge they make their pulleys in-house.
That's what surprised me when I looked inside my Core One yesterday.
So far, I've only found the original Gates pulleys and idlers (with the dimensions I need) in US shops.
Replacing the original Gates pulleys with Prusa pulleys (i.e., Prulleys 🤣 ) for testing purposes would, in my opinion, be a good start to ruling out internal production tolerances at Prusa.
RE: Wavy mystery, unacceptable quality
As an aside, I find reading the Gates catalog or design guide humorous. To paraphrase: Gates pulleys are intended for prototype or low volume use. The pulley profile is proprietary. We'll tell you what it is, but you might have to sign an NDA. Even then, there are dimensions we might not tell you.
So, they don't want to sell a lot of pulleys, but they do want to sell a lot of belts. IMO, it would help the latter if they just published the optimum profile!
Another interesting thing about the belts is the part number. LL stands for long length. When you buy smaller circular belts, the internal cords are parallel to the belt. Long length belts (LL) are cut from a much wider belt, with the cutter moving sideways (like peeling an apple). Thus, the internal cords are at a slight angle to the belt. I doubt it matters, but it's an interesting piece of trivia.