This sounds really interesting. Do I understand that your system uses a
hopper feed of granules? That was the next step that I wanted to take
with our filament extruder (details here:
[
reprap.org]).
I'm impressed that you can get the torque needed from a stepper. Do you
also need the precision? (For a possible cheaper alternative, see here:
[
reprap.org]). Or would just an ordinary DC
electric motor do?
If you are using EVA then you must try polycaprolactone - that melts at
about the same temperature, but has the mechanical properties of nylon
when it's solid. It's much more rigid. I have a small amount in
granular form. Let me know how many grams you'd need to try the
experiment and, if I have enough, I'll airmail it to you free of charge.
Best wishes
Adrian
Dr Adrian Bowyer
[
staff.bath.ac.uk]
[
reprap.org]
Evan Malone wrote:
> Tim,
> Great news - I'm very happy to hear that you have had success! By the way,
> Dr. Adrian Bowyer of the RepRap project in the UK (www.reprap.org) has
> been interested in seeing a RepRap screw extruder integrated with a
> Fab@Home chassis. Your work is very much along these lines. I've cc'd
> him here. Perhaps you can explain your experiences integrating your screw
> extrusion tool with him?
> Also, may I impose upon you, when you have time, to contribute to the
> Fab@Home wiki? It would be wonderful if you would create a page
> describing your tool design and integration linked from the "Deposition
> Tools" pages. Also, if you have any information you could contribute to
> the user manuals, we could really use the assistance.
>
> Best wishes, and I very much look forward to the photos (and video, if you
> can provide it)!
>
> Evan
>
>
>> Evan,
>>
>> We will update you with photos of our machine on the Fab@Home website ASAP
>> but
>> just to let you know we have successfully built our first few models.
>>
>> Using EVA copolymer (hot melt glue) in the heated cylinder being deposited
>> using the screw extruder driven by a stepper motor had great results. Due
>> to
>> the 0sec layer wait and the speed at which this material was able to be
>> deposited, we were able to make the pyramid at 3x scale in approximately
>> 25mins with excellent accuracy for an uncalibrated machine initial trials.
>> The
>> hard finish is great.
>>
>> Over the next few days we will further calibrate the machine and hopefully
>> construct some impressive models to be posted.
>>
>> As using this screw extruder is a continuous process we have no need to
>> stop
>> the machine for pauses and with our added hopper can make large models
>> unattended however should we still insert pauses in the fabrication
>> process so
>> the x and y motors dont overheat or simply add small computer cooling fans
>> to
>> them as we have with the deposition motor or should we not require any
>> pausing
>> for the x,y motors at all?
>>
>> Thanks for your time,
>>
>> I look forward to posting the initial pictures.
>>
>>
>> Regards,
>>
>> Tim Nixon
>>
>
>
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