When we last updated, we'd just recieved our IGUS bushing samples and were starting to test them. TL;DR - everything now works, all problems are behind us, and we're getting ready to ship out units. We did have to make one other design change, and knowing our luck the lathe malfunctioned halfway through last week - but everything is finally confirmed and ready to go. The grinder grinds, the extruder extrudes, the diameter control system controls the diameter...things are good at ReDeTec!
What follows is a quick overview of how testing went, what changes were made, and what happened with our lathe...as well as a quick trip down memory lane to show how well our filament is doing these days. And, a very brief update on the pellets, as Amazon is proving more difficult than hoped to get working.
Testing + knife edge
Just to make 100% sure the bushing wouldn't fail under any circumstance, we wanted to test all kinds of feed material...ABS pellets, PLA pellets, recycled bits, etc. A huge shout-out to Mosaic MFG for donating some of their wipe towers to us - this meant we didn't have to extrude filament, print with it, and then grind it...we could just go straight to the grinding and re-extruding.
PLA and ABS pellet testing worked flawlessly, and now that the auger was no longer rubbing anywhere we actually had higher throughput for a given torque/pressure...always a good thing. We did run into a slight hickup with recycled material, though...very thing and long strips could get pulled into and pinched between the auger and the bushing. With some further investigation and comparison to our "old" methods, we noticed that because there was no "metal to metal" contact at the end of the feed throat, the overly skinny material could deform the bushing ever so slightly, and get stuck/pinched between the bushing and the auger. The diagram below might help explain this.
Admittedly somewhat difficult to explain, but here goes - in the top left photo, a skinny piece of recycled material is about to get pinched between the auger and the bearing. In the top right, we see what can ends up happening...the piece of plastic compresses, but also deforms the bushing slightly and ends up stuck between the two. In the bottom left, the plastic is about to get stuck again...but now we've added a hardened steel plate (in blue), which shears the recycled bit into two halves, so nothing gets caught as shown in the bottom right.
The obvious solution and one we've now tested extensively with all forms of input material was to add a hardened steel face just after the feed throat entrance and before the bushing. This hardened face meant that anything that started getting pinched would simply shear apart, instead of getting caught between the auger and the bushing. After running through many more spools of recycled and raw material, we've approved this design and are ready to move back forward with production!
Of course, it just wouldn't be a normal week here without something else going wrong. Our Okuma - made in the early 90s - decided it wasn't going to take all of this progress sitting down, and promptly started having some major issues with it's CRT display. Sometimes it would go all white, sometimes it would go all black, and sometimes it would flicker between the two. This put a serious hamper on our progress in debugging the drive section, as turning new variants to test now had to be done by hand, which of course takes *much* longer. And, of course, we need that lathe for production!
Thankfully, Alex was able to debug the issue as a problem with the 12 volt supply line to the CRT control circuit. We "borrowed" a PSU from our production line, hacked it into the main PSU, and things have been working fine ever since. The lathe is now back up and running around the clock to catch up with production, and help get units shipped out.
Yoda version 2
Weirdly, despite all of the purge towers Mosaic gave us being completely different colours, the vast majority of our filament came out as a uniform green...I could not tell you why. Nevertheless, it seemed like the perfect time to 3D print a new Yoda. Our original Yoda is by far our most popular sample print, but it had seen more than it's share of wear and tear...and if we're being 100% honest, was not as good a print as it could have been to begin with. Yoda was one of our very first prints, before we ran our Indiegogo. The tech worked, but had a way to go, as evidenced by the inconsistent colour and the "gap" layers evident of poor diameter control. The new yoda, printed yesterday when we officially approved the final cold section after endurance testing with recycled material, has none of those issues. It's one consistent shade of green, has no gaps or issues with the print at all, and is made of recycled material (the original was virgin). We printed it on default PLA settings, at 0.1 layer height, without supports or rafting, on our makerbot Rep 2 - as that's what printed the original Yoda. Check it out for yourself!
Despite having spent months working with Amazon on this, we're not quite there. The issue is that as a Canadian company trying to sell on an american website (amazon.com), the tax implications are...not trivial. We're trying to work with them to speed things up, as this is the last step of getting our pellets listed, but it's proving more difficult than we'd hoped as there are quite a few forms to fill out, lawyers to consult, and accountants to question.
Well, that's a wrap for now - our next update will be the start of shipping, which we're extremely excited for. Given we have quite a few sub assemblies piled up, we should start making up for lost time relatively soon. And, as always, thank you all for your patience and support!
-The ReDeTec team