Monthly Archives: April 2014

Recycling plastic for 3D printing

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I have been using basic 3d printers since 2011, starting with a Thing-o-matic  by Makerbot, then a couple of UP3D machines. They use plastic filament, mostly made of Acrylonitrile butadiene styrene (ABS), the same material used to make Lego bricks, or polylactic acid (PLA), a plastic derived from corn starch or other renewable bio-materials. The filament is generally made from virgin plastic (ie: not recycled), purchased ready-spooled and in various colours.

The frequent use of a 3D printer has a common side-effect: the production of a significant amount of faulty parts and temporary support structures, without even counting in the endless tat spewed out by the little machines in the guise of Yoda heads, clumsy plastic jewellery, door knobs that don’t quite work…

Additionally ABS plastic perfectly suitable for printing can be found in the casings of many consumer electronic items, car bumpers, fridge door compartments, lego bricks, luggage etc… The problem is how to turn this abundant source of potentially upcyclable material into suitable filament. The most spectacular and impressively robust use of recycled ABS in a 3D printer is Endless, a project by Dutch designer Dirk van der Kooij based on a modified robotic arm.

The search for an environmentally friendly solution to the needs of desktop 3D printers is underway. The Filabot was probably the first attempt for an open-source solution allowing both the re-use of discarded prints and of recycled plastics. Filabot is now providing a commercially available grinder, the Reclaimer, as well as different models of filament extruders.

 

Other commercial designs include and the Strudittle and the Filastruder. Open source designs can be found on the Recyclebot website. Joshua Pearce from Michichan Technological University made the news in 2013 for his recycling of milk jugs using a Recyclebot v2.2, design available on Thingiverse. Beyond the fact that high-density polyethylene, or HDPE (the plastic milk jugs are made of) retracts dimensionally while cooling, the recycling of plastics presents the inconvenient that polymer chains do break down in smaller chains each time the plastic is melted, thus weakening the material and limiting the amount of useable cycles.

Filastruder recommends a pellet size of no more than 5mm width in any dimension for use with their machine. I experimented briefly with an office paper shredder and some of my discarded prints. The coarse plastic fragments I collected are not suitable for a small extruder, and the shredder struggled to cut anything thicker than 2mm.

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In November 2013 the UK based techfortrade charity launched the Ethical Filament Foundation, an initiative aiming to reduce plastic waste in developing countries while providing income to deprived populations. Their vision: ” We believe that there is an opportunity to create an environmentally friendly and ethically produced filament alternative to meet the needs of the rapidly growing 3D Printing market. We also believe that by doing this we could potentially open up a new market for value added products that can be produced by waste picker groups in low income countries.The foundation is working on a manufacturing and quality standard “.