FFSAKE I put so much effort into my belt alignment and now this
I put so much effort into getting my belts evenly tensioned or so I thought. I was confident I had eliminated all friction as much as possible and now this WTF. I guess I should replace the belts now presumably. My understanding is that you can get gates ones which are better quality, anyone know where from? Also any tips on how to ensure its doesn't happen again? I scrutinized the pulleys and belt motion so this baffles me.
37 Replies
generous-apricot•2y ago
I have a feeling that the bearing stack design is not so good since the flange is not big enough. Also the belt coming from RatRig is not of amazing quality.
I agree. My belts were fine until I upgraded to 3.1 I absolutely think the flanges on the bearings are too small to keep the belts in place.
If all your pulley shafts are truly vertical, and pulleys are properly spaced, there is no reason for them to 'walk' off the pulleys. Rim to rim Looking closely at that pic..... it looks like the toothed side is what is deteriorating. The bearing stack is 10mm flange to flange. You belt is 9mm (actually 8.80mm) wide. 'Technically' the belt should never even touch the flanges... yes I know...in a perfect world.
QUESTION.... is that fiber stuff building up anywhere else besides what you pictured here? If not, you've found what is rubbing/wearing the belt! Looking at your graph, tells me your belts are a bit on the loose side, (freq range) so could easily be wearing against the aluminum rails (belt return route) There is negligible clearance there. The belts are stiff enough to not bend perfectly around the pulleys as they exit pulleys heading towards and away from the extrusions. You should be able to look down the length of the Y extrusions and see space between belt and extrusion. (albeit small space) If not, it just further supports the idea of belts not tight enough.
QUESTION.... is that fiber stuff building up anywhere else besides what you pictured here? If not, you've found what is rubbing/wearing the belt! Looking at your graph, tells me your belts are a bit on the loose side, (freq range) so could easily be wearing against the aluminum rails (belt return route) There is negligible clearance there. The belts are stiff enough to not bend perfectly around the pulleys as they exit pulleys heading towards and away from the extrusions. You should be able to look down the length of the Y extrusions and see space between belt and extrusion. (albeit small space) If not, it just further supports the idea of belts not tight enough.
eager-peach•2y ago
Thanks for your input guys I will do a postmortem over the weekend
generous-apricot•2y ago
In the ideal world it would indeed stay in place. However, it looks like my belt has some uneven local tensions inside.
I recommend doing the dual motor plate mod from ffb and get rid of the printed parts of the motor cage
much better visibility, alignment and access
correct-apricot•2y ago
Ill probbaly do the dual plate mod too as I had the same issue. I moved my drive gear on the motor down some though and it stopped the rubbing. But still the bet is bad looking now.
I personally never ran any of the oem RR supplied belts. I went right to the high temp real Gates EPDM belts right from the start. Much stronger, can handle temps better heavier duty, let alone not a knock-off.
to answer your orig 'source' Q...I got mine from
https://west3d.com/search?type=product&options%5Bprefix%5D=last&options%5Bunavailable_products%5D=last&q=GATES+GT2+EPDM+High+Temperature+Open+Belt+LL-2GT-E+%286mm%2F9mm+wide%29
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There is no such thing as perfect alignment. Everything made has a range of tolerance. Even the aluminum extrusions are not perfectly straight. A good corexy design is one that can handle an expected level of small imperfection in the build without belts eating themselves. Because the 3.1 flanged bearing approach results in guides with much smaller grooves to retain the belt position, the result is a printer that requires near perfection in the build to prevent premature belt wear. I built my 3.0 with the same level of care that I did the 3.1 upgrade. I had no substantial belt wear on the 3.0 machine after many hundreds of hours of printing. The 3.1 machine started eating the belt after maybe 3 days and I can't see where my build is bad.
eager-peach•2y ago
Does anyone make proper pulleys for the 3.1 with soft contours at the edges?
You should be able to find a common frame reference point, and validate that all the pulleys are on the same plane (level) I did not rely on just the oem instructions for spacers (maybe because I mod'ed stuff as I went) but belt rubbing is not an issue that is not correctable by moving spacers around and making sure bearing stack pivot rods are all parallel to each other across all corners of the machine on the same plane.
eager-peach•2y ago
WTAF! £116 for 5.8 metres
??? oh.... s/h costs? 60x100 was 89.40 USD (84.85 EUR) for me $7 in s/h
like-gold•2y ago
@elcoj where can I find some details about this mod? Are you talking about awd?