This section documents steps towards a tool ecosystem around the fundakit. The focus is on low-cost open-source designs which expand transformative potential of design activities and spreading actions. In the tradition of open-source, we are working with and building on existing designs, and shaping them for new contexts. Tools are primarily aimed at not-for-profit community-based institutions promoting youth inclusion. They are being designed and tested in collaboration with young people from these institutions. The tools can be used in combination with the fundakit but are not dependent on it – i.e. they can be used with other tools or in stand-alone applications. Projects are listed below.
An extruder for upcycling post-consumer plastics into 3D printer filament. Working with Michigan Technological University and Aalto University RepRapable Recyclebot as base design. Initial areas of work include a new heating system, new software system, new diameter sensor PCB, and a graphical user interface. Also a revision of the barrel design, as well as local or in-house manufacture of components not accessible in developing contexts.
Concentrating on PETE (Polyethylene terephthalate) water and cooldrink bottles as primary feedstock source – PETE uses the P1 resin idenfication code. Bottles extracted from the local environment, washed, dried, and cut into sections. Side strips flattened and fed into standard document shredder to be cut into 2X15mm flakes for extruder. Top and base of bottles made from thicker more rigid plastic. Other applications and shredding processes being explored for these parts.
Heating System Tests
(below) Induction heating system using Tesla coil. Coil fitted around extrusion barrel for temperature tests. Barrel at 255’C, PETE melting point temperature. The coil fits over the barrel and does not make contact at any point. Energy transferred to the barrel without the use of wires. Barrel attached to hopper frame, from where plastic flakes fed into system. Latex sheet used to inhibit heat transfer from barrel to hopper frame.
Puller and Spooler Assemblies
(below left) Work-in-progress puller assembly. Running threaded rod through roller drum core and large belt pulley with power drill. Roller drums printed locally to avoid importation. Consist of hard PLA core and soft outer layer printed with flexible filament. Motor mount – being held on the right – adapted for locally available motors. Puller determines diameter of the filament. The faster it pulls the smaller the diameter; the slower it pulls the larger the diameter. (below right) Work-in-progress spooler assembly. Fastening the printed crossbeam onto bearing towers. Spooler is the system which winds the newly produced filament onto spool. Bottle bases – top left of image – used for nut, washer, screw, spring, etc. storage.
(below) Removing PETE bottle flakes from document shredder bin and storing in 5l water bottle. Using standard office shredder designed for cutting 8 pages at a time. Shredder performs mico cut, cutting bottle side sections into 2X15mm flakes. Bottle sections bent flat at point of entry to shredder, and fed one at a time. Recommended shredder cooling times respected.
Testing Software Modules
(below) Uploading and testing software modules for cooler fans and motors. Fan and motor wired to RAMPS 1.4 shield plugged onto locally manufactured (same specs) Arduino Mega 2560. Fan speed being adjusted through software. Fans used in cooling assembly to cool newly extruded filament and an aluminium trough running along the assembly – which guides and also cools filament. Motors used in puller, traverse and spooler assemblies.
Temperature Sensing and Mount
(below left and right) MAX6675 k-type thermocouple mounted to heating barrel with common hose clamp, to measure barrel temperature immediately before extrusion. The MAX6675 is a simple SPI serial interface temperature output. 0 centigrade to +1024 centigrade temperature range, with converter resolution of 0.25 centigrade temperature. Barrel, nozzle and base locally manufactured. All screw apart for cleaning.
Micro Wind Turbine
Capturing energy from the local environment to charge batteries, powerbanks and other devices.