This extruder is designed to push a large volume of paste trough a bowden-style tube and into your choice of nozzle. It uses a stepper driven piston to push the paste making it easy to control using your current stepper controller (i.e. ramps, rambo, etc.) I designed the nozzle to mount onto the cap of a inkjet refill bottle. Stay tuned as I will update the nozzle to be a bit less part specific. Enjoy!
In addition to the attached printable parts, you will need:
3 x 8mm nuts
2 x 8mm washers
1 x ~400mm x 8mm threaded rod
1 x 350mm x 1.5in sch. 40 PVC pipe
1 x 1/8in NPT hose clamp
1 x 1/4in air tubing (as long as you need)
1 x 10mm M3 screw and nut
2 x 608 skate board bearings
3 x 3in 6-32 screws
3 x #6 washers and nuts
6 x 1/2in 6-32 screws
2 x 1.5in x 1/8in o-rings
1 x NEMA 14/17 stepper w/ mounting screws
Drill and drill bit set
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1) Print the parts using >15% infill. (ABS tends to work better than PLA)
2) Fit check the parts and clean up burrs as necessary
3) Assemble the piston by nesting one 8mm nut into the piston itself, then thread in the rod until it bottoms out. Slide a washer over the rod and secure in place with another 8mm nut.
4) Carefully slip an o-ring onto the piston
5) Push both caps onto the PVC and drill and tap the holes as necessary
6) Remove the caps and apply a small amount of Vasoline to the piston. Carefully slide the piston assembly into the tube.
7) Press one skate board bearing into the stepper end cap and screw onto the PVC pipe
8) Push the piston assembly until the threaded rod passes through the bearing. Slide an 8mm washer over the threaded rod
9) Press the last 8mm nut into the drive gear and thread onto the rod. Slide the last 8mm washer over the threaded rod
10) Press the last bearing onto the top mount and slide over the threaded rod. Secure in place using three standoffs and the 6-32 screws
11) Mount the stepper on to the mount and press on the input gear. Secure the gear in place with an M3 screw and nested nut
12) Screw the NPT hose fitting onto the front cap and attach your hose. Attach the other end of your hose to your nozzle mount (which should probably be attached to your printer.
13) Fill your extruder with the goop of your choice and screw on the end cap.
14) Give it a test drive and configure your slicer/controller for accuracy