Making the bits from bytes extruder working

Like so many of you, we also got some problems with the extruder from bits from bytes... For the sake of all of you, we'll post a small tutorial on how to really make it work:

like my partner said in the question of Thomas Larkworthy:


"you've had the same problem we did... almost simultaneously... the bits from bytes extruder works very well! on paper... when you use it on the real world, it has some flaws... But they can be corrected!

About the extrusion strength: the current design only works for about 5 min... after that, doesn't allow to push the wire with enough strength... the way we found to correct that is to take the screw out, and with a hand saw make the threads deeper, around 1mm deeper. after that, get a triangular sander and sharpen the edge of the threads, so that they can carve well on the plastic wire. last, but by far not least, get a new ball bearing... you will simply use it to press the screw up, instead of the silly washer... that will only send you screw to hell... with the bearing, you manage to press the wire against the screw, and manage to carve it well, and no more problems...

About the heat, only with thermal insolation we manage to roughly get 200 degrees in the barrel (measured with an independent calibrated device)... So, time to upgrade again... longer barrel, with 2 independent heating wires, heated by pwm 1 and 3 (just hotwire the pwm3 signal to pwm1 in the arduino/sanguino). after that, 260 is easy to get, without insulation!

about the reflux, that is a little trickyer to solve... insulation or not, you need to put something very tight with the wire, so that the melted plastic doesn't come out. even so, the extrusion speed must be slow... one way which worked not for long was to make a hole in the PTFE barrel, and screw it to the heating barrel! but the contact was not perfect,a cavity was present between the screw and the barrel, which induced some plastic to stuck in there, and obstruct the exit of the wire... still working on that detail... I hope that tomorro it will be solved... the only true problem, is that when we have everything right, and do everything you're supposed to, it doesn't move when you press the final print...."

What version of the extruder are you talking about? I know that there is the 2.0.1 version, but I am not sure if that one is also used in the 3.0 that they are selling right now. It makes me confused to hear people talking about the "BfB extruder" without telling me which version...

we are talking about the version 2.0.1. by want we've saw about 3.0 version, it's seems to us that there will be no problem about the extrusion strength. However, there may still be common problems with 3.0 and 2.0.1, unless they have also changed the extruder barrel configuration and its closing point with the wire.

Version 3.0 is completely new, same principle but all parts purpose engineered for a much easier build. The V2.0.1 has printed for days on end at various shows etc but does require quite careful setting up

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Ian
[www.bitsfrombytes.com]

Ok, I just have enough headaches with this machine... even after the mods, the extrude just doesn't have enough reliability. The principle of having a screw pushing the wire just isn't good enough. Just works well on paper. even if it carves well, with any resistence it just stops extruding because it destroys the wire. and then, you loose hours and hours of work, not to mention the patience. so, we'll have to make a TRUE extruder... It may be fun to use it as a hobby, but when a company asks you to make it work, then you just realize that you must start from the scratch.

Sigh