Direct granules 3D printer V2 - Hackaday Prize 2020

I was close to delete my this years HackadayPrize entry since there was no going forward in the development of my direct extruding 3D printer, however past week I made the breakthrough I had been working for. The very near end of this years Hackaday prize turned my video studio into a huge mess, but let’s have a look at the current stage of development before time is out: The main idea is to have a machine that can turn waste plastics into granules and from that into something useful like a constructional element if you are an engineer or a sculpture if you are an artist. For now, I get my granules with a commercial blender. The raw material is then filled into a homemade sieve to get only granules below a diameter of 2mm. I have ideas for an own, simple to build blender with an integrated sieve mechanism, but time was too short to create that, yet.

01:14 - With that raw material inside my newly created extruder you can do 3D printing as usual. The really tricky thing was to build an extruder that performs reliably - my previous builds never worked for hours, but thats what needed in 3D printing. The latest build now extrudes with a constant rate for hours and days. That extrusion rate is constant when turning your printer on, after running for several hours and even in case you ran out of raw material and had to refill the Extruder. Clogging was another issue that caused headache: Whenever that occurred, I had to clean the whole extruder to make it work again.

02:00 - With the new design that problem is solved as long as there aren’t too many, tool large impurities in your raw material. To get there I did not simply use a more powerful stepper motor - the one used here is the rather small motor that shipped with the cheap printer I am using for these experiments. The path I went was having a close look at what caused the clogging issues and iterating design parameters to get rid of that error. Here, the extruder is used to create a really tiny print with the dimensions 27x25x12mm. The layer hight is set to 0.2mm, and the print speed is 10mm per second. Stringing is an issue of the extruder version shown here, but only minor changes can eliminate that, as I have seen in previous iterations of my designs - I will show that in coming videos.

02:54 - For now I am happy to finally have a first, reliably working prototype of a granules extruder giving me reproducible results. A better mechanics and a part cooling fan that is mounted on the print head rather than laying on the build plate will improve print quality. With a reliable extruder you can start printing larger objects - this is the part with twice the size. Of course larger prints should be printed with higher speed - here I am printing with 40mm per second. Even with 4 times the speed of the previous run, the plastics is extruded constantly with the needed higher rate.

03:37 - Now that the extruder runs fine, I am at the point where tinkering ends and engineering starts: I can start fine tuning the design and examine where the limits are. Another thing to come is documentation: To me, open source doesn’t mean its done after publishing the design files - its demonstrating in detail how things work and explaining step by step why I did the things as I did them. This is a quick look at all the internal components. As you can see, its hand made with a conventional screw as core element. Looks simple and that what it is, but before I got here… …

I had to see many similar versions fail over the past months the Hackaday prize was running. Why those similar designs failed and what makes the existing one a success will be explained in coming videos - stay tuned! So lots of time consuming work ahead of me - I’ll go back to my workshop and my not so tidy video studio. Thanks for watching and: “I’ll be back!” .