Easy "frictionless" spool holder mod
Hi Everyone,
As a new Prusa I3 MK3 owner I'm really happy with the included plastic molded spool holder that comes with the printer.
I however wanted to reduce even further the friction between the plastic molded part and the spool itself, so I've designed this addition that allows for much lower friction: https://www.thingiverse.com/thing:3196873
It does require 2x Ball Bearings: 6805 2RS (61805) 25x37x7mm as extra parts, everything else is printable and it's just 3 pieces 🙂
The only downside using this is that it reducese the usable spool diameter between 46mm and 65mm, so if you have a spool which has a narrower hole than 46mm you may still need to use the stock part.
Please share your feedback on this part, I'm happy to make further improvements if needed/requested 😉
Re: Easy "frictionless" spool holder mod
My Prusa injection molded spool holder broke, specifically at the obvious weakest part where it clamps to the frame. After mentioning this on reddit, it seems this is not so uncommon. I would suggest this project might not prove to be very popular based on this. In fact, I will go so far as to say that ANY spool holder that ignores the concept of 'center of gravity' should be rejected outright.
Re: Easy "frictionless" spool holder mod
There is a small problem with such a spool holder. I have manufactured a similar spool holder with ball bearings.
The problem is that the friction is so low that the coil wants to roll itself up.
I have therefore fitted it with a friction brake to eliminate that problem.
Bear MK3 with Bondtech extruder
Re: Easy "frictionless" spool holder mod
There is a small problem with such a spool holder. I have manufactured a similar spool holder with ball bearings.
The problem is that the friction is so low that the coil wants to roll itself up.
I have therefore fitted it with a friction brake to eliminate that problem.
I have not yet encountered such problem, I will be on the lookout for that 😉
Re: Easy "frictionless" spool holder mod
My Prusa injection molded spool holder broke, specifically at the obvious weakest part where it clamps to the frame. After mentioning this on reddit, it seems this is not so uncommon. I would suggest this project might not prove to be very popular based on this. In fact, I will go so far as to say that ANY spool holder that ignores the concept of 'center of gravity' should be rejected outright.
Was the part replaced?
By the way this sounds it seems that part could break even with a heavy spool or could've been a bad manifacturing batch?
Re: Easy "frictionless" spool holder mod
I have not yet encountered such problem, I will be on the lookout for that 😉
I would recommend to abandon it immediately, just to be safe. Having as much as 2KG of spoolage crash into your print sheet is an unpleasant experience.
Was the part replaced?
By the way this sounds it seems that part could break even with a heavy spool or could've been a bad manifacturing batch?
I wont be requesting warranty coverage for the spool holder, for me it's simply not worth the risk of another failure. There are so many printable alternatives available. Here is the one I'm using. While it is incompatible with the Prusa frame, the design is brilliant:
https://www.thingiverse.com/thing:2140685
The center of gravity is correct, and the filament feeds almost perfectly straight down towards the center of the bed.
Re: Easy "frictionless" spool holder mod
Woah, well I'm not going past 1kg load per arm on that spool holder.
I can't find 2kg spools at a convenient price in my area but I would assume that everything has a "maximum load" and it's not just "prusa's weak plastic mold".
It would be interesting however to get an official confirmation from Prusa on how what is the maximum load it is recommended to put on each of those spool holders arms.
Re: Easy "frictionless" spool holder mod
Woah, well I'm not going past 1kg load per arm on that spool holder.
I can't find 2kg spools at a convenient price in my area but I would assume that everything has a "maximum load" and it's not just "prusa's weak plastic mold".
It would be interesting however to get an official confirmation from Prusa on how what is the maximum load it is recommended to put on each of those spool holders arms.
NO I had two 1KG spools, less actually since they weren't unused.