This is a super-simple belt driven syringe-based extruder for viscous or non-newtonian fluids such as peanut butter. it uses the MakerBot MK6's 100oz-in stepper motor to provide the necessary force, and applies pressure to the syringe via the mechanical advantage of a belt based reduction. This potentially also increases the resolutuon of the steps/volume, but very little experimentation has been done with fine control of the flow rate.
This model was designed around scraps I happened to have laying around, but it works really well.
This extruder was co-designed with Scott Beibin in July 2012, specially for use in the Groucho Fractal Show - www.grouchofractal.com