Filament guide

Update 2024-03-13. I had a few cases where the part fell off, and broke. I increased the dimensions to make it more robust. See “Housing-improved”.

Update 2024-01-14. On request I added a version where the surfaces of the left and right holder are pushed back 0.2 mm. I have not tested it myself (My prints were fine) so please give me feedback. Thes V2 versions you have to slice yourself and do not forget to add supports. 

When I print with PETG or TPU I print directly from a dryer box. This dryer box is normally placed next to the printer (see pictures). To guide the filament as stress free as possible you need some type of guiding system. There are already several filament guides here and in the internet. However I wanted one as high as possible and mountable on the printer itself. Therefore I created this guide roller that can be mounted on the spool holder for the Prusa MK3-4.

I used a standard 608 roller bearing. If you don't have one you can print this model https://www.printables.com/model/70024-parametric-roller-and-slide-bearing .

After printing you likely have to polish the surfaces of the threads and the ball a bit for smooth operation. 

In both halves of the fork that holds the bearing there are 3 small holes. Here you can insert a small, 3 mm, piece of filament to align the fork when you screw it in.

Assembly is pretty straightforward. Push the “wheel” over the ball bearing. This is a tight fit and likely needs some force. Then place the bearing inside the left and right holder. Three little pieces of filament will help. Put the lower ball from the top in the housing and screw the holder all the way in it. Tighten it a bit. Then screw the top half of the ball on it. Add the lid. Do not tighten the lid on top of the ball too much. It must be able to move freely and so align itself optimally. Clip the guide on top of the spool holder.

In operation the roller will align itself automatically. When everything is smooth, you could add some lubricant. I use silicon oil.

In case you want or need to modify your dryer box I also have some feedthrough here: https://www.printables.com/model/84039-filament-feedthrough .

When you like this design please rate it. When you print it please post a make.