[Lab] Plastic for makerbots

Sat Feb 5 11:06:54 EST 2011

There are several teams in the reprap and makerbot communities working on
granule extruders... There are a few more challenges than you would expect.
(and as you pointed out, they are fairly big and heavy (compared to the
current filament extruder designs), meaning the print head may need to be
stationary).

Many of the current projects focus on extruding granules into usable 3mm
filament, that way the existing 3d printer designs can make use of it, and
you have a simple standalone extruder for processing granules into usable
filament as you need it. (would also let you mix dye into your filament for
custom plastic colors and so on in small batches).

Another added benefit of a granule extruder is that you could then throw
your botched/sample/test parts and purge extrusions, and any other "waste"
plastic into a blender, chop it up into small granules, and recycle it back
into usable filament again. Which would be very useful indeed.

Several of the current designs use a large (3/4" or larger) auger drill bit,
(normally quite long like 12") and a matching pipe of appropriate diameter
(to fit snugly around the bit). This design creates a plastic pump which can
accept granules, and they melt in the heated pipe until they are able to be
extruded out the other end.

Currently many of the existing challenges are around isolating the heat to
one end of the pipe. It tends to work it's way back during operation (the
bit is metal and so conducts heat well) causing the granule feed to
eventually clog, because granules get sticky and plug up the works...

Another problem is stop/start... Once you stop the unit, the plastic
hardens, sealing the whole thing shut quite nicely... Requiring a fair bit
of heat to re-melt it and allow the auger to start turning again...

Definitely not insurmountable problems, obviously it's done in industry, but
I think the challenge is doing it fairly small, cheap, and usable for the
hobbiest...

I have WAY too many projects on the go at the moment, but very soon on the
list is getting a granule extruder working (to this end I've been saving all
my scrap plastic since I started with my Mendel, and I currently have about
2lb of scrap, ready for recycling).

Anyway, if anyone decides to endeavor down this route, I would definitely be
interested.

- Paul

On Sat, Feb 5, 2011 at 7:58 AM, Darcy Whyte <darcy at siteware.com> wrote:

>
> If plastic comes in granules, then why not make an extruder that accepts
> granules?
>
> Perhaps some sort of a bin and a heater. Especially if you had a moving
> platform rather than a gantry.
>
> I'm planning on making adhoc stuff rather than production with my extruder
> (when it arrives). So I'll probably live with whatever suppliers the
> community is using for makerbots and stuff.
>
> But on another project I am planning on manufacturing some propellers. I
> haven't figured out how to do that yet but I might need to figure out where
> to buy bulk plastic for that.
>
>
>
>
> On Fri, Feb 4, 2011 at 1:19 PM, Paul (Maker Engineering) <
> paul at makerengineering.com> wrote:
>
>> Makergear is in the USA, as are all the other 3DP suppliers I've been able
>> to find.
>>
>> I order mine from Ultimachine (I use PLA) and pay a fair bit of shipping
>> to get it here.
>>
>> One of the problems with PLA is that there is only one manufacturer in all
>> of north america that I know of producing it, which is NatureWorks. In
>> addition there is another in the Netherlands. So if you order straight from
>> them in very large quantities it gets fairly cheap.
>>
>> ABS is easier to source because there are manufacturers all over the
>> place.
>>
>> NatureWorks doesn't normally sell it in 3mm filament either, but they do
>> sell it in granules (as most suppliers sell). But most manufacturers will
>> sell filament as well for an additional cost (basically because they have to
>> take the granules and extrude them into filament for you). This is why
>> granules are cheaper, and why so many are working on building granule
>> extruders to be able to extrude our own filament.
>>
>> Many suppliers and distributers also have the ability to extrude 3mm
>> filament because it can be used in plastic welding. But is normally cut into
>> short lengths, so with a special request you can likely get spools of
>> continuous 3mm filament in Ontario (specifically in the GTA) quite easily...
>> I believe several of the hacklab.to guys were mentioning they had a
>> supplier in the toronto area that was able to provide them with very large
>> quantities of 3mm abs filament for a reasonable price.
>>
>> Hope that helps!
>>
>> - Paul
>>
>> On Fri, Feb 4, 2011 at 12:14 PM, Darcy Whyte <darcy at siteware.com> wrote:
>>
>>> I ordered a small amount to get started at:
>>> http://www.makergear.com/
>>>
>>> Not sure where they are from their web site.
>>>
>>>
>>>
>>>
>>> Date: Thu, 3 Feb 2011 20:11:32 +0000
>>> From: emteeoh at gmail.com
>>> Subject: [Lab] Plastic for makerbots
>>> To: lab at artengine.ca
>>> Message-ID:
>>>
>>>  <872190262-1296763893-cardhu_decombobulator_blackberry.rim.net-2144851823- at bda256.bisx.prod.on.blackberry
>>> >
>>>
>>> Content-Type: text/plain
>>>
>>> Hi!
>>> I've got a quick question: I'm wondering if you can tell me where you're
>>> buying plastic for your makerbot? I'm assuming there has got to be a better
>>> way to get it than importing it from new york, but none of the plastics
>>> suppliers I can find in toronto seem to sell 3mm filament.
>>>
>>> Thanks!
>>> Sent on the TELUS Mobility network with BlackBerry
>>> _______________________________________________
>>> Lab mailing list
>>> Lab at artengine.ca
>>> http://artengine.ca/mailman/listinfo/lab
>>>
>>>
>>
>
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