but i have been able to use the other two feed paths of the extruder, i had some fun with nozzles and such but thats another post..
so basically the extruder works as far as i have been able to test, i have to make a little mod to actually have the material change to happen, so far i have had no cam shaft installed. i am starting to think my measurements are wrong..
i am learning how to use solid works so i will draw up what i have and animate the movements to double check things..
then the smaller one with all the broken blades cools the print for the first layer and maybe bridging when it all works better.
you can also see the dove tail join that hold the extruder in place, and leaves it removable for when i need to work on it, its a bit tight and i have been hitting it to free it up... bad me :(here you can see where the cam shaft with a 40tooth gear on it would go in the bearing and across the tension arms/blades the cam shaft has 180' sections taken out @ 90' to each other, this leaves one position where they are all free or one is gripped by the hobbed bolt.
when i built this extruder i used all the conservative numbers where i could so this unit is probably a little on the large side, i picked the positions of the fulcrum points by eye and what i thought the motors could handle not what they can handle.. stepper motors are very easy to under estimate... i could probably have gotten away with a smaller motor for the cam shaft, i think once i complete the rebuild i will have a better idea, maybe i will be able to make it printable. then others can enjoy this as well.
i lost a little print area when i installed the triple extruder but it was only 40mm in the X..
i need to replace the hobbed bolt some day soon.. i also need to install stronger springs to get better grip on the filament
one problem i had was that because my hobbed bolt is so far away from my heater barrels my filament bowed out and refused to go down the nozzle. this was easily fixed with a little brass tube from the hobby store, this was pressed into the peek block that i have holding my three nozzles, this extruder could easily be extended to accommodate more materials with only a 10mm increase in over size in the X axis with my current install but that could also be taken from the Y axis.
my nozzles are made from 5/8th brass threaded rod that i machine down the thread off and wrap with kapton and nichrome wire. i use 100k thermistors. started out with 0.5mm and now want 0.25mm holes.. but thats another story.
So far this has been giving me good filament up to about 1000mm/min but i need to install harder springs and better hobbing to get better speeds, once i ditch the lead screws i will have lots more speed in my movements and needs a extruder that can keep up..