This is a smooth and 100% silent filament feed guide for your Anycubic i3 Mega.
Due to the slight curvature of the hole for the filament tube, the filament retains its "natural" curvature and is not guided too tightly or forced in an unfavourable direction. The tube flexibly adapts to the forward and backward movements of the extruder and the degree of bending of the filament (see video below).
After an unsuccessful search for a silent filament guide that doesn't make any scratching noises when the filament is fed, I designed this very simple model. It's a first draft, but it works perfectly. Perhaps the model could be embellished a little; feel free.
For a standard 1.75 mm filament tube, I would enlarge the model in the slicer to 109% and print it lying on its side. On the side position the hole for the filament tube becomes evenly round. The tube must fit tightly in the hole of the guide, which has a slight curvature. But with a little patience, it can be turned in without any problems.
For further accessories you need:
1x M3 15 mm screw
1x M3 washer
8 cm filament tube (e.g. standard tube for 1.75 mm filament)
Cut the tube with a very sharp knife, e.g. a carpet knife, without compressing or deforming it at the cut. I wouldn't use scissors to cut it.
Some models that I have tried in the past and with which I was not completely satisfied:
This pulley model is very popular and has a nice design, but it produces permanent, scratching noises when the filament is pulled over the plastic roll, especially when the filament on the filament roll tapers towards the end and the filament becomes more "unruly" as a result.
This filament guide model is constructed with much devotion and follows the right approach with the filament tube, but in my opinion the filament feed is made difficult by the almost 180 degree angle of the construction and the extruder does not feed enough filament in places.
I have combined my filament guide with this incredibly great filament roll holder. These two modifications work together perfectly.
About 23 minutes print time, easy to install, simple but effective.
Well, many words for such a simple model. Just try it out. I would be happy for some feedback.