Recycling plastic for 3D printing


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.


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 “.


Chip for Human Brain project


In Manchester today, doing some preparation for a 2015 exhibition called The Imitation Game in Manchester Art Gallery. Curator Clare Gannaway is looking into possible collaborations with the School of Computer Science of the University of Manchester. Today we met Steve Furber, a legendary figure of the computing world who was one of the lead designers for Acorn’s microcomputers in the early 1980’s. After the success of Acorn’s BBC Micro, he was a crucial contributor to the invention of the ARM chip, the descendents of which can be found at the heart of today’s vast majority of mobile phones and tablets. I felt a bit star struck, as it was with BBC micros found in UK skips that I discovered (late) the joys of physical computing.

Steve Furber with one of the first SpiNNaker working units

Prof Furber talked to us about the SpiNNaker project he is currently leading, well on its way to complete a machine featuring an array of one million specialised ARM chips. The machine’s processing power will be equivalent to 1% of the human brain’s. The machine will be used by scientists from various disciplines to run experiments aiming at understanding the least understood intermediary level of brain processing, between neuron firing and high level activity monitoring. This effort is part of the international Human Brain Project.


Each SpiNNaker chip, designed in the lab, made in China and Taiwan, features 18 core processors. The machine will feature approximately 56000 of the super thin chips, mounted on individual boards carrying 48 units. A massively complex operation, running in 10 wardrobe-size units. Steve Furber told us of an analogy he uses when he talks to secondary school students about the complexity of modern electronics and of the chip architects’ job: the connections and routing in a smartphone’s ARM processor, if scaled up, would be equivalent to all the roads on earth. The architects’ job is to make sure all the roads go to the right destination and that there is no traffic jam. Daunting.

We visited the SpiNNaker labs, where we saw one of the first operational machines running, some mysterious programme with lots of pretty flashing lights. We also had a look at the graphene lab, nanotechnology research heralded to produce great things in the near future. I only know of graphene in relation to promising new designs for supercapacitors. We could see researchers wearing what Furber called bunny suits busying themselves on high tech gear, working on nanoparticles.

TAROS 2013

I was in Oxford at the end of August where I presented the Coy-B project at the 14th TAROS conference. TAROS stands for Towards Autonomous RObotics Systems. It is attended by an international crew of specialists from academia and business. I was hoping to make contact with interested robotic scientists who would share my view that it is important to reflect on what are these cybernetic creatures and what would a cybernetic wilderness be?

During my short presentation I noticed that one member of the audience was nodding vigorously. He introduced himself afterwards and we had a couple of good conversations in the next couple of days. It is too early to disclose the details, but I was invited to present the project to his team, which went well. Hopefully a collaboration will get started within the next few months, depending on funding. Watch this space…


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