I am working on a project for a resin print, and I have access to a Formlabs Form 4B printer. I am trying to figure out which resin to use, as I have really tight tolerances on the parts (20 µm clearances, and some features are only 100 um tall, which is only ~70 μm deep if printed at 45°). I also need something that is waterproof.
I know that this is a lot to expect of any printer, but I have been told that resin printers are my best chance to get this to fit, and I was able to get 20 µm clearances to work with a Prusa CoreOne FDM printer with PETG filament (though I had to adjust the xy dimensions of the model to 100.5% and bolt holes to 105% to get close to the model dimensions). I have also seen people talk about achieving successful prints with zero clearance fits without having to modify the print using a Formlabs Form 4B.
I am trying to figure out which resin to use that is going to give me the best precision and accuracy of prints. Because of the small features, I am planning to print at a 25 μm layer height. It seems that my best options are one of the V5 resins. The only one that mentions specific tolerances is the grey, which they say is 0.15% (lower limit is 0.02 mm/ 20 μm). Both the black and clear only state that you can achieve precise tolerances and fine features. Grey also seems to have the best mechanical properties of the three (this is for a mechanical device, so these properties are import to take into consideration, and having some flexibility in the material isn’t a huge issue).
I thought about using one of the engineering resins, such as the durable, rigid, tough, or precision resins. The Precision Model resin achieves 100 μm accuracy, which isn’t sufficient. Both of the tough resins (1500 and 2000) are a minimum of 50 µm layers, as are both of the rigid resins (4000 and 10K) and the Durable resin, which is going to leave the tiny features almost non-existent. I also don’t know anything about the xy precision for any of these resins.
What have you found for accuracy of prints with different resins? Have you found the V5 resins to be durable and wear-resistant, or do they easily break under real-world conditions? Do you have a resin that you would recommend?