Lot of issues to look out for:
- use a lot of back pressure to remove air from the melt
- as stable melt temperature as possible. Any deviation here creates filament diameter differences.
- use a winder
- use a strong high torque motor and cooling for it.
- filter the molten filament
It did cost me quite a while to get nice filament out of the system but still not finished with it. I need to find way to remove the last occasional air bubble in the filament. Just ordered the parts for a automatic filament measure and control system so I don't have to monitor and adjust the filament diameter manually.
I am running at the moment Chi Mei polylac Pa-758 This has a MFI 3 at 5kg 200deg C . This mfi gives me about 1kg/10hours. This is a clear ABS plastic. I started with this, because you can see any junk and air bubbles in them.
Plan to try other abs types, nylon and maybe even PC in the future,
The extruder is a bit of stainless 1/2inch tube and a heater.
Internally there is a filter and a breaker plate to help increase the pressure in the extruder head
Some grinded granules do fall out of the air holes drilled in the pipe.
Nice work! Have been really keen to try making one of these to shred junk plastic, rather than paying for pure filament. Can you shred other types of junk plastics, like HDPE milk jugs or plastic bags? Not too concerned with the colour, even if it's PakNSave yellow
Never tried anything other than abs granules. The granules are only about $9/kg.
Likely you need a lot of bags or bottles to make up a kg of plastic.
If you like to shred things, why not use the plastic from a fridge or washing machine? Much more bulk in them.
Also you can buy recycled abs granules.
But whatever source of recycled plastic your choose, it has to be clean. If there is any junk in it, you will block the 3d printer nozzle.
Edited 1 time(s). Last edit at 02/27/2016 11:58PM by wingmaster.
I only used virgin granules, never recycled ones. But I came across the following sites in nz while searching for granules:
In the last one of these sites listed specific abs granules, but don't see it listed any more.