recycling and extruding pla

[beverageexpert]

reading this other post got me to start thinking of extruding my own
filament. I have a fair amount of scraps and pieces that didn't print.
What do you think the best way to break them down would be? I would
like to powder or pelletize them. PLA is super hard I don't want to
kill any appliances yet.

Here is my experiment that I will be trying.
I will be using a thrift store pasta maker to attempt to extrude the
filament.
I figure the auger drive should be strong enough to push it. I just
wonder if powder or fine pellets would work. I figure I would make
some type of heater core that could be a metal tapered cone with a 3mm
opening wrapped with some nichrome and a thermistor. Does this sound
somewhat feasible?

bryan

[degroof]

I bet one of those Blendtec blenders would work. Kinda expensive
though. How about a coffee grinder?

[jakero...@gmail.com]

This is something our group is very interested in looking into in the
future. Keep us updated with any testing you do!

[C. Sahagun]

The extruders that turn PLA pellets into filament are pretty beefy
machines -- thousands of psi of pressure and thousands of ft*lbf of
torque. Just something to remember if you don't get great results
with a pasta maker.

You can try dissolving the PLA in a solvent, cast a film and then cut
up the film. The film will be a bit like cellophane so it may be
easier to get it into small pieces. (To cast a film you can simply
put the solvent/polymer mixture in a container and let the solvent
evaporate). Here's a list I found of solvents for PLA: http://bit.ly/drlP1L
The downside is that most of these solvents are stuff you can't buy at
your local hardware store, but it's something to consider if a blender
doesn't perform well enough.

There's an instrument used to measure the Melt Flow Index of a polymer
that may be a good inspiration for a cheap extruder. A simple
imitation would be to take a metal tube and position it vertically.
Wrap a bunch of nichrome wire around it to heat it (this is the
critical part, you'll have to play with it to get the temperature and,
even more importantly, the temperature gradient, right). Then simply
put your chopped up scrap at the top, stick a weight on it and let
gravity do the rest. There are a couple of problems with this method
(may be a pain to wrap, unwrap, clean, rewrap, etc. until you get the
temp right; you're probably limited to producing a few feet per
batch), but it's very cheap and a pretty simple machine. Poke around
online to see if you can find a schematic and maybe a better
description of "Melt Flow Index" (here's a simple one I found:
http://polymer.w99of.com/images/mfi.jpg ).

Let us know what you end up doing and how well it works.

Sahagun

[TeamTeamUSA]

I just created a wiki page to collect plastic recycling ideas:

http://wiki.makerbot.com/plastic-recycling

Feel free to add to it.

Go!

=ml=