My MSc student Arman has modified his auto-head-changer (which always was for Mendel, not Darwin) to design and make a quick-change plug-unplug mechanism for the Darwin head. You have to take the head off quite often when you're setting up the machine, and also when you're using it. Before, that took about 15 minutes of fiddling with cap screws in hard-to-get-at places. Now it takes a couple of seconds.
The next thing we'll do is to make two heads: one for CAPA and one for HDPE so we can swap them ad-lib for experiments. We'll also put the balloon paste extruder on the same mechanism next to this one for support experiments.
I'm not sure if we want to change the Darwin design at this late stage, but this certainly makes things easy...
Looks like it might benefit from another design iteration or two. Still, good start! :-)
ReplyDeleteYes, being able to easily remove a head is a good idea. With Zaphod the head was static, isolated and relatively easy to maintain. In Darwin it looks like fixing head bugs will be easier if the heads are easily removable.
ReplyDeleteVik :v)
Wingnuts are a wonderful technology for that sort of thing. Mind, you have to make the mountings big enough to accommodate them.
ReplyDeleteWingnuts are particularly useful for adjusting the springs on the extruder head.
ReplyDeleteVik :v)
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ReplyDeleteThis is my answer to wingnuts:-
ReplyDeletehttp://hydraraptor.blogspot.com/
2007/08/knobby-nuts.html
It should be possible to make them with FDM and captive nuts.