Although not much to look at, our first plastic extrusion was very promising. The first extrusion was produced during our extrusion motor sizing test. The extrusion screw was connected to an RPM sensor, torque sensor, and cordless drill. The 3 separate heating zones were heated to 200 C and cordless drill was used to turn the extrusion screw while pellets were fed into the hopper. The torque sensor was set to save the maximum torque reading and the extrusion screw RPMs were recorded using Arduspreadsheets. We were only able to extrude this small amount of material before the 3D printed drill adapter broke. From this test we were able to accurately size a DC motor for our extrusion system.

The dark color grey-like color of the material is due to left over oil and metal particles from the extrusion barrel manufacturing. In future tests the raw material became a cleaner white color as the system cleaned out.

We used ABS virgin plastic pellets purchased from supplier. We chose ABS as our first material to test incase of a barrel jam, acetone could be used to clean the extrusion system out. Also ABS has a higher heat tolerance and is less likely to burn if system over heats.

The natural ABS is colored with a red plastic dye. Only ~20g of plastic dye is needed per 1 kg of ABS pellets to produce a vibrant red color.

For our first spool of filament we produced about 250g of ABS filament. The accuracy of our filament is still only within plus or minus 0.15 mm in tolerance which from our testing, can be printed without jamming the hot end but prints lack dimension accuracy and surface quality is not on par with bought filaments. This inaccuracy is mainly due to the fact that the filament diameter is controlled with an open feedback loop where the user changes pulling speed and extrusion screw RPM until the filament is close to the desired diameter. Once the closed-loop PID system is integrated into the system we should see a substantial improvement in diameter accuracy.