Plastruder MK4 Prototype

This is a derivative of the Plastruder MK3 design I've been working on. The goal is to make the plastruder into a printable design that can be made on a MakerBot. I also wanted to take on an ambitious project to put the new AOI plugin, MetaCAD through its paces. Learn about metacad at http://www.metacad.org

This extruder design uses 5 printed pieces: two halves that bolt together for the housing, 2 dinos to put it at the right height for printing, and a simple insulator retainer to keep the PTFE in the right spot. The rest of the design is mostly the motor, heater barrel assembly, electronics, and a 625 bearing to provide the pinching force. It has yet to be tested, but ideally it will be simpler to put together, as well as a sturdier design with no squeaks! I've printed all the parts on my travel bot, and as soon as I get home, I'll be assembling them and testing them out.

A few design notes:

• no more layered construction! that was a hack to make it laser-cuttable. new design is two halves bolted together. one half holds the motor + filament, the other half holds the idler wheel.
• idler wheel switched from acrylic + 608 bearing to a single 625 bearing. smaller, more compact, and nothing but a nearly indestructible bearing to break. should be quite a bit more consistant
• 4 adjustable screws with captive nuts for setting the pinch wheel tension. you'll be able to adjust it on the fly, without any sort of dis-assembly. hopefully the abs will act as a sort of spring as well

a few things i'd like to change yet:

• rotate the captive nut slot on the right-housing to be in-line with print direction for a better finish.
• switch the captive nut / bolt head holes between right and left housings to improve print quality for both (adjust on right side instead of left side)