My experiment of mixing 25% Tough with 75% Standard Black resin had very good results. As planned I did use the standard resin setting rather than open mode so I would have heat and wiping. Because the tough is quite a bit more viscous than the standard resin, I watched it carefully during warm up and made certain the mixed viscosity would not make a wave and overrun the ends of the tank, which it did not. I did notice the printer pausing several times during the print to verify resin so the printer knew something was amiss but not enough to stop the process.
The parts were much closer to PP injection molded parts than any of the resins I tried with the standard resins too stiff and brittle and the tough too pliable and hard rubber like. I purchased flexible resin but based upon the results of the tough I did not even bother to try it for this set of parts. Most of the parts I have printed have had issues with curing, even after placement in the UV chamber for extended periods of time, immersed in water, not immersed etc. I usually end up placing the parts in the sun outdoors to get rid of the final stickiness that seems nearly impossible to get rid of. I see some posts about a IPA substitute cleaner from the printing industry, but I don’t know if that would be better at removing the layer of uncured resin that clings to the parts post print. Disaster struck when I placed my blended resin parts in the sun for final curing. Both parts got a chalky white appearance and deformed badly in the sun. Brought them back in but the damage was irreversible. I printed another pair, shortened the UV cure time and DID NOT expose them to the sun and they are much better. I sprayed them with UV blocking clear coat so we’ll see how they look over the next couple days.
Bottom line, the results were much closer to PP than any Formlabs resins, but still a long way from being PP clones. I see Xlab has a PP clone resin available for their SLA desktop printer, so hopefully Formlabs is getting ready to release something similar. In the meantime if anyone has any suggestions as to what I might try to modify my experiment in trying to get as close to PP as possible I would appreciate it. As a product developer most of the products that come in are for PP, PE or other commodity grade injection resins and the closer I can get my results to mimc PP the more business opportunities I see being possible.