Experiences with ABS from local waste disposal provider

Hello I don't know if I am right here but maybe someone can give me hints:

I am building a Filament Extruder with ABS waste plastic directly distributed from a local waste disposal company. Are there any experiences with these materials? It seems that I need much more power for the auger, because the material is not round like pellets.

Here is my blog deltaprinter.blogspot.co.at/p/filament-extruder.html where you can see images of my machine and the plastic I am going to use.

Thank you for any hints...

Sehr interesant!

So are the plastic chips bigger than the pellets one would normally purchase?

Some plastics may need higher temperatures(260°C or even higher?). I think the ABS filament usually used for RepRap printers is a lower tempurature formulation(235°C or so).

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Yvan

Singularity Machine

If you are unable to process the plastic in your extruder, you'll need to regrind the plastic to reduce the size.

The main question I still have while looking into building a recycle is how much the plastic deteriorates after the 1st use. If that is not a problem you could pass the ABS two times through the machine. The 2nd extrusion would then much smoother I assume.

@ sungod3k

The first time that you are extruding the recycled plastic it will have been melted/processed (degraded) 3 times,
you bump it up to 4 times on your first pass through.

This paper has a lot of good data for the DIY recycled ABS.

Findings: After the first injection mouldings, minor decreases (ca. 2.0 %) in the tensile strength were observed.
After the next injection mouldings, this quantity did not change much. The melt flow rate increased along with
the number of injection mouldings. The glass transition temperatures (from DSC) of butadiene and acrylonitrile
styrene fractions don’t vary with the number of injection mouldings and are ca. 61 and +104ºC, respectively.

Originality/value: It has been observed that the largest changes in the tensile strength and melt flow rate of
ABS occur during its first injection moulding and a melt flow rate increases slightly with the number of injection
mouldings. The temperatures of phase transitions and thermal as well as the storage modulus and damping
coefficient of ABS do not essentially change after repeated injection mouldings.
[www.journalamme.org]

Fresh pellets could be added to the mix in controlled ratios to keep things within spec. I suppose.

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Yvan

Singularity Machine

Hello,

thank you for your replies! I was on vacation this weekend...

My selfmade heater can heat up the material up to 230 °C, but most of the DIY extruders are working with 180 °C and normal pellets. Maybe my temperature is really too low and I have to get the exact specifications of the material.

@Yvan: Thanks for the mixing tipp. I have now purchased some pellets.

@A2: Thank you for the paper.. I am going to have a look at it as soon as possible!
The material differs in size but it is small enough for my 20 diameter auger. In my case it should be possible without regrind the material, which seems to be hard.
I try to extrude 1.75 mm filament and the size of my nozzle is exact 1.7. Maybe I should make a bigger hole what do you think?

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Edited 1 time(s). Last edit at 12/01/2013 03:48PM by scvo.

For the 3mm ABS I've been using to print with, temperatures are set between 230 and 240°C.

I suspect you might need to test hotter for ABS that was not originally designed for low temp extrusion. I'm seeing 270 to 280° as the high end for injection molding, but I don't know if that is truly required, or just the limit of what the plastic itself can handle for a few minutes.

I'm thinking if you have just a small amount of chips in the mix that melt at 240°C and the filament extruder is set to 230°, the unmelted chunks will act as plugs! Someone much more familiar with ABS would have to step in right about now and give more accurate info.

How long in the 1.7 mm section of the nozzle? The longer the bore at 1.7 mm, the harder it will be to push ABS through it. Ideally, the section that is 1.7 mm would be very short. This will have a big impact on extrusion pressure.

Edited 1 time(s). Last edit at 12/01/2013 07:26PM by Yvan.

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Yvan

Singularity Machine

A little quick over view you might find usefull:

Injection Moulding Guide

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Yvan

Singularity Machine

Hi,
the hole length of the nozzle is very short (1mm max.). To get hotter I have to redesign my heater, but its not a big deal. I will do that this week and then I hopefully my pellets are coming and I will going to mix it.
Thank you for the Injection Moulding Guide, the last page (troubleshooting) is very cool.

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