This is an experimental replacement for the larger of my two silent Rapman extruder gears.
After extensive printing with the silent gears, some 'click-clack' noises started to reappear, probably due to friction wear.
This gear attempts to solve this problem once and for all by incorporating a spring into the gear which itself is about 1.5mm larger in diameter. The spring provides constant pressure between the extruder gears, removing the tolerance and therefore the noise.
The big unknown of course is whether it will be durable and effective in the long term!
Update 22/2: The test gear survived a 5-hour torture test that contained a lot of reversals. The noises are gone, but this is most likely due to the gear simply being bigger - the teeth ring isn't flexing around the hub like I wanted. Basically, it's too strong. I think a new design with 6 (rather than 8) spring units is next on the todo list!
This design is currently being tested with Orbi-PLA as its supreme elasticity lends itself well to the design. Theoretically however, any plastic should be suitable since the spring components do not move more than a millimetre.
To print this gear successfully you will need an extrusion width of no more than 0.5mm, as that is the width of the spring elements.
Obviously, you will also need the smaller extruder gear from the Silent Extruder thing :)