Grey v3 and clear v2 - creating interlocking parts

Hi form labs!

Ive been printing out some of my first test models and after a couple of fails seem to be improving
one of the things i wanted to get a bit of help on is that i have a design I’m working on where there are several interlocking parts some are intended to be using the grey v3 resin and some to be using clear v2 resin, Ive added a tolerance of 0.1 gap to help with making them easy to re-assemble later after printing but have noticed that the grey parts has shrunk quite a bit in some parts of the model where it interfaces with some of the clear parts.

My design is under NDA at the moment so i cant post pictures of it publicly but would be able to send some pics to someone @formalabs perhaps.

I’m yet to get a curing set up happening for some of my clear prints Ive just been putting them in the sun for 20 mins.

Would aircon in the room where the printer is that’s set to cool be affecting it and warping it a bit as its printing?
just trying to get a handle on whats expected as far as different materials and their known shrinkage characteristics are or if its just the lack of curing straight after / aircon being too cool possibility.

Its summer here, air con is helpful to stay sane on hot days maybe the printer likes being kept around 30 degrees C?.


If you want dimensionally repeatable parts let them set overnight to evaporate off any IPA in the part. Then post cure.

If you have a part that just seems to shrink you may need to scale it up a little to get it to fit. Formlabs has done a fairly good job calculating the shrinkage on their materials but the part design can move things around a bit. I do this in Solidworks but Preform can also scale your model once you measure the percent change you need.

Part orientation in the printer, support amount and size, height above the base and time before removal after finishing the print can also have influence on the dimensions.

thanks for the replies @fantasy2 and @FredB
I’m interested in your comment about the time before removal after finishing, as some of them may have been hanging in the printer after finishing at 3am for a hour or three before i got to them…

these are some of my first test prints and they are fairly curvy complex shell style geometry about 2.5 mm thick - maybe I’m a bit ambitious to think i can divide up a shape and print it in different resins and get it to fit back together easily.

i was thinking of adding some extra cross bracing in the larger openings to help with keeping the shape that are removable later as i think you cant have different sized support connections in preform.

seems like theres a whole lot of variables to try and play with to get a good balance, with resin being $250/L its pretty easy to burn a few bottles to get things right especially if i need to print one and then measure it to figure out shrinkage / supports etc are ok or not.

maybe its better to print with all one material like clearv2 and then spray paint the opaque parts later, than try and print different resins to get clarity / opacity variance. especially if the shrinkage prevents certain complex forms from matching back up easily…