Tag Archives: digital fabrication

Recycling plastic for 3D printing

absShredsBanner

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.

plastic-in-indonesian-river

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 “.

 

Owl project studio

Owl Project's Anthony Hall and Simon Whitemore

While in Manchester I took the opportunity to visit my friends from the Owl Project in their studio round the back of Piccadilly Station. Anthony Hall, Simon Whitemore and Steve Symons have scored a large space split in two sections: one dedicated to (mostly) wood fabrication, with a CNC router and some more traditional cutting tools, the other for brain work, electronics and small scale projects.

The space contains several of Owl Project’s FLOW installation instruments. FLOW was commissioned by Cultural Olympiads fund in 2012, and installed on the Tyne River in Newcastle UK for several months. Mounted on a specially designed floating platform, a water wheel activated several beautifully crafted wood and electronics instruments that analysed water samples and generated sound accordingly.

I also saw a few solar-powered iLogs (if you want to make one, there is an iLog workshop coming soon) and current work on various synths, sequencers and light spectrometers. The Owl project are currently developing new work during a residency in Manchester Museum.

Visit to Access Space Sheffield

accessOut

I visited Access Space in Sheffield, where I enjoyed a two days crash training in using the command line and shell scripts in Linux. Initiated by James Wallbank and the Redundant Technology Initiative group in 2000, Access Space is arguably the first open source/community computing creative technology labs in the UK. The space is open several days per week, with two main areas: the Media Lab where visitors can access a Linux workstation for web access, design, programming, etc. A code-protected door opens on the Refab Space which hosts the digital fabrication machines (laser cutter, CNC router, several rep rap 3D printers), a lot of recycled computing gear and several solid workbenches.
During my stay I saw lots of activity in both areas, including a Sheffield Hardware Hackers meeting (every monday 6pm), and the laser cutter was pretty much always busy.

James is a great host, busy with many projects including his latest business adventure Infinite Crypt. He is always keen to share on topics of technological accessibility, community development and techno-social trends. I recorded an audio interview where he gives us his insight on Access Space and thoughts on the opportunities offered by digital fabrication technologies.

Interview with James Wallbank in Access Space Sheffield, 26th February 2014

Supercapacitor + Raspberry Pi

I have been interested in supercapacitors for a while. These components are boosted up versions of the humble capacitors found in most electronic products. A capacitor is a component that can store energy, in a similar way to a battery. Normal capacitors – aka caps – only take very small charges (typically measured in Microfarads), and they are often used for cleaning up spikes and noise in power supplies. Supercaps can store much more (measured in Farads), which presently makes them almost suitable as battery replacements.

scrapBatteries

What’s wrong with using batteries?
– They take a long time, and fairly complex charging circuits, to charge. A super cap can be plugged in a standard power supply with addition of just two components, and charge in minutes.
– They have a limited life span, generally around 1000 charges, after what they have to be recycled, a tricky business. In theory, a well-treated super cap will last almost forever.

I have run a couple of tests with current supercapacitor technology. I found all the info I needed about supercapacitors in this instructable.

Super capacitor battery, 8V 120 Farad

One if my experiments was to build an 8.1V, 120 Farad capacitor array, that should be sufficient for powering a small robot or microcontroller. It is made of 6 x 360Farad, 2.7V supercaps. First test: to supply power to a Raspberry Pi. It works fine, but with this configuration (8V 120F converted to 5V) I only get approximately 15 minutes of operation, and that’s without powering a display.

The bright side is the speed of charge, around 3 minutes with my bench power supply (2.5A).

Erm… Not sure what these supercaps will be good for, maybe a secondary power for mobile robot. The fast recharge rate could make it a good combination with a conventional battery to provide continuous operation.

Broken spindle

My old Chinese CNC router was cutting away a piece of plywood to make a housing for a supercapacitor power unit when I heard a crunching noise and a squeak, with smoke. The spindle of the router had finally died, after several months of decline.
Today I received my new spindle, a German one (Kress 1050 FME-1). Fear not stereotype, the German tool is definitely better than the original. It took a bit of twiddling to make it fit, including the 3D printing of a bright orange excentered collet to fit the narrower mount of the new device.
routersI had to lift up the work table by 30mm, which I did with crudely sawn MDF pads, not the job I am the proudest of… The plan is to eventually cut an aluminium plate mount to drop the spindle by 30mm and fit the table back to its original position.

Anyway, by the end of the day I had cut the three parts for my supercap battery housing. tomorrow I am off to Flowering Elbow’s open day near Carmarthen, where maybe it will all come together!