For the last few years, the must-have feature that companies are competing to show off on their filament deposition 3D printers is multi-material printing. Be it tool swapping or a material-changing system, everyone wants to show they can give you the capability to make multicoloured plastic tchotchkes. So far, that hasn’t really been the case in the world of at-home resin printing — until now. A company called Polysynth, headed by a fellow named [Eric], hopes you’ll pay a premium for the ability to make multimaterial resin prints, and they show some interesting use cases in the video below.

The technique is simple: instead of one resin tank underneath the dipping build plate, [Eric]’s Polysynth printer has a carousel of up to eight small circular tanks. To avoid cross-contamination from uncured resin, the print needs to be cleansed between alternating dips in the different resin vats. Rather than add a wash vat and slow the process down that way, [Eric] and his team decided to use centrifugal force: they just spin the print really, really fast to fling all the uncured resin to the sides of the vat. Yes, really.

The hard part isn’t the resin-removing spin cycle — the hard part is stopping the spin at the precise orientation the part started at, to within a few microns. For that, he’s using a sort of kinematic linkage to lock the spinning portion back into place using a servo. It seems to work, based on the demonstration in the video embedded below. Even better, [Eric] shows off a resin conductive enough to use for fully printed, multilayer PCBs. We doubt SLS will ever compete with traditional fabs on volume, but for fast turnaround without waiting on parts from China, the conductive resins could open up some killer apps for this kind of printer. That and dental: printing gums and teeth of dentures in one solid go is likely to appeal to users in that space.

What do you think? Tipster [Aaron Tagliaboschi] was interested enough to send in the video, and we’re grateful that he did. It’s early days yet, and you cannot buy one of these machines just yet. Since it’s a commercial product, you’ll be starting from scratch if you want to build your own.

It wasn’t that long ago that the only way to get a home resin printer was to build it yourself, and it’s still an option that might save some coin. If you go that route, why not try spinning? We hear that’s a good trick, so let us know if you try it.