The first part that I modified was a piece of the MK2.3 extruder. As I didn’t have the right bearing and that lever is a stock part from the MK2 extruder, it was very easy to just download the openSCAD file from Prusa’s GitHub and edit it accordingly. After a first test, the bearing was too low as I hadn’t changed the center point of it yet. The final fix was to do just that and now the filament seems to be pretty close to tangential with respect to the bearing.
I havent tested the extruder yet, becuse the heater and thermistors have to be mounted and configured, but it’s looking good.
So the idler now takes a regular 608 bearing and the little rod that holds it in position can also be found on my GitHub / Thingiverse.
|Before and after changing the center point (It. 2 \ 3)||Iteration 1 (original) and 2|
With my Anet A8, I made the experience that cheap linear bearings from China tend to be very low quality and PLA bushings are often the better option. In my honest opinion, 3D printers being as light as they are, don’t necessarily need those heavy-duty ball bearings.
The bushings that I liked most are some that you cuetomize in openSCAD and are printed in vase mode. Using trial and error you try to get the perfect size with minimal drag and as little wobble as possible. Because of good experiences with them, I printed these bushings for my new MK3 clone as well.
Y-Axis Bearing / Bushing Holders
A downside of the spiral vase bushings is that they don’t hold their outer shape very well, so they always need to be inside something that holds them from the outside.
For the Anet, there is a specific model on Thingiverse that I changed in openSCAD to fit my Prusa MK3 heatbed carriage.
X / Y Axis Idler “Bearing Housing”
A completely new model, designed from scratch was the “bearing housing” for 623h bearings that Prusa ships out of aluminium.
With the help of one of these bearings and the printed Y-axis idler I could design and print a few prototypes until it fit nicely.
This model can also be found on my Thingiverse profile