You’ll know from previous posts that I’ve been searching (and pleading!) for a resin that has the qualities of ABS. Something aimed at end-use manufacturing. This segment is growing fast in SLS and FDM but somehow totally neglected in SLA. The qualities that I need are:
- High rigidity and tensile strength (similar to ABS)
- Not brittle (which eliminates just about all Formlabs resins except durable and flexible)
- Heat resistant to at least 70C (which eliminates durable and tough)
I’ve been experimenting over the last year by mixing all sorts of Formlabs resins, sometimes with interesting results. For instance I found if I added 40% Tough to Grey Pro then suddenly I stopped getting failed prints and the parts are stronger. However they are still brittle so wasn’t the answer.
I recently ended up with a mixture that gets pretty close to my requirements. It’s 40% Rigid and 60% Durable, printed with Rigid settings. I just call it R&D. I cure it at 60C for 60 minutes but haven’t seen any difference when I tried other settings. The result is a strong part, very similar to ABS, without the low HDT of Durable and without the brittleness of all the other resins. It’s by no means indestructible and still retains some brittleness but practical enough to make “real stuff” out of. It’s now my go-to resin for just about everything. We recently printed some non-structural parts for a racing car and despite the extreme heat cycles and sudden splashes of cold water, and being man-handled between races, the part held up beautifully. The aim was to test heat resistance and sudden temperature changes over a few days. The parts worked well.
It will be great if some of you guys can try this mix and share your findings. If it works maybe we can convince @Formlabs to make this available as their first real “additive manufacturing” material!
Of course the ideal will be heat resistance over 100C as with ABS so maybe I’ll do a similar experiment with the new High Temp resin and Durable. Not sure how rigid High Temp is though.