Then Comes the Idea for the Triple Material Extruder
This was probably conceived at the wrong time not actually having a decent frame to put anything experimental on to.. but that's how things happen here
So i you all saw the plastic creation that i made as my first extruder. well things i learnt from that were your motor should be as big as you can move! it never be too strong!..
armed with this and a bit more i goes off to my fabricator mate, who actually possesses the skill of welding, all i can do is apply bird turd... i stopped at the hardware on the way and arrive with some nice aluminum angle, that i proceed to start measuring and marking, a quick consult with him and the design is modded.. the bits all get welded and i start drilling and cutting and pondering and drinking beer, it was a hot day....
at the end i had a beast of a creation that consisted of two nema 17 stepper motors with 20:1 and 40:1 worm drives, one drives a camshaft that pushes my tension arms. the other drives a hobbed bolt like a wades except my bolt was hobbed in three places 10mm apart.
Against these 3 hobbed sections i have three 13mm idle wheels that run on roller bearings 7mm OD 3mm ID held with M3 screw. the theory was that when the camshaft released the tension arm and the spring the idle wheel would pinch the filament against each hobbed section of the bolt.
so the extrude motor would turn the one bolt and the camshaft would be turned by the other motor so that the camshaft is in one of four positions, filament #1,2,3 and none.
a micro switch is mounted so the MCU knows when the camshaft is in the NONE position, software settings and firmware will allow the selection of materials on the fly with only little time between material changes, you may need to move to the dump position to clean the nozzle to make sure of a nice change. but its still quicker than a human change..
pictures will follow soon