Just working on an extruder design in sketchup. There will be a couple rubber bands in between those two pegs for the pressure on the filament against the drive wheel. Thoughts? Any suggestions? Also, is it against the sketchup make (free version), to share models under the gpl license? I know you can’t sell your models but can you open-source them?
I have not had good experience with rubber bands as tensioners on equipment.
@Chuck_McManis hmmm. I might need to rethink that then. Would anything else work between those two pegs besides rubber bands? Or should I edit the desing to use a spring?
Well you will need some compliance (springyness) because things like filament width will vary. You can either apply it to the arm or the bearing.
My experience with rubber bands is that UV turns them brittle and heat turns them gooey, so they fail often.
you could rest the axle that goes through the bearing on a leaf spring, basically a piece of spring steel which is tensioned when the wheel is pushed away from the grub gear. Then a latch or connecting bolt to hold the bearing arm to the assembly can be used for fine adjustments. (like in some extruders there will be a screw which adjusts spring tension)
@Chuck_McManis alright sounds good! Thanks for the advice!
The filament needs to be trapped as much as possible or else it will escape just after passing the extruder gear.
Rubber bands will fail within 2 months while compressed or stretched for the duration.
As said, rubber is not the way to go.
Also, you only pull the lever from 1 side, this will slightly skew it. This could potentially cause issues.
(I also recommend switching to DesignSpark Mechanical from Sketchup. Sketchup is pretty bad as CAD tool)
Ditch the rubber bands and use a coil spring.
Want tons of springs? I found a pack of 200 assorted springs at a store called “Farm and Home” for $5 or $6.
for the second part of your question, you can share design with the community on http://youimagine.com with a choice of licence.
@StephaneBUISSON even if I have the non commercial license of sketchup?