@BastiDE Beautiful machine!
I am using these wipers to keep the tubes clean: https://www.thingiverse.com/thing:3965343
Those do a good job especially when milling aluminum, however due to the design of the MPCNC there are still some ways for chips and dust to get in between the bearings and tubes. So for wood or plastic a dust shoe is definitely the best option.
@ben78
Bei E3D gibt es original Gates Riemen in verschiedenen Breiten zusammen mit den entsprechenden Pulleys. Ich würde definitiv 9mm Gates Riemen den 15mm aliexpress-Riemen vorziehen.