I am investigating building a repstrap machine with minimum funds and trying to avoid complicated electronics (ie. stepper motor boards).
Has anyone looked into whether the feed stock can be 'pushed' into the extruder head using the same technique as a chauking gun?
Namely that a sleeve is placed around the feedstock which is pushed forward/backward, on the forward push it grips the feedstock and pushes it into the heater element and on the backward push it slides along the feedstock allowing more to be fed on the next forward push.
The figures I have seen about seem to suggest that the extruder 'motor' needs to be capable of around 2KG worth of 'push', and extrapolating the volume/hour suggest 15cm of feedstock per hour.
The benefit of this would be that the extruder could be controlled by a switch (or two). Turn the heater on, and when hot turn on extruder and press 'print'.
Mungewell
