Auger feeder remix

thingiverse

This started as a remix to make the auger more printable by splitting it axially. The original auger is difficult because of the constant overhang and printing with support is a huge PITA. The split model prints each side flat and is glued together afterwards (you'll need to flip the halves down on their long sides before printing). This also makes the shaft much stronger. It doesn't take much glue (superglue or epoxy) to join - the joint at the base is most important. I didn't bother gluing each of the screw "threads". A ring is then glued around the base to strengthen the glue joint against the force of the set screw (opening centered on the setscrew hole). I progressed to remodeling the trough as I didn't want to use melt-in inserts. The motorplate fasteners are now a 5mm bolt and plain nut. I also much reduced the printing time and filament usage by reducing the solid volumes. It's in two pieces, mostly so I could check the bottom half for fit before sinking hours of print time into it. Dec 18 Rev: In getting this working I made some changes to the files. Mostly they serve to prevent or at least minimize pieces of cat food getting caught in the works and stopping the motor. However, it is very difficult to prevent that completely, so I have the motor go forward approx 45 degrees and then reverse for 10, and repeat as needed. When a piece of food gets caught and stalls the stepper, the reversal serves to dislodge it. The slanted plate is glued in place after other assembly and is to prevent a lot of food dumping out the end sporadically. The amount dispensed was very uneven when the end of the auger was exposed. Now I can dispense 33 grams (about 1/4 cup) within a gram or two using four full auger rotations. (I'm sure the plate could be modeled into the other bits but the hardware was progressively modified as it came together, so there you go.) For control I used a Raspberry Pi, Pi Touchscreen and Adafruit Stepper motor hat. The stepper I got off of Amazon. The combination of Adafruit hat and not particularly strong stepper turned out to be perfect. The stepper stalls when a piece of food is caught rather than breaking the auger or trough.