Form 2 better at flat surfaces than Form 1+?


I am not new to 3D printing, and we have owned our form 1+ for a few years now, but recently we have tried making injection molds from our form 1+, and have been running into issues making larger parts with flat sides, and parts that do not warp mid print.

We have essentially been trying to make a mold cavity that fits into a 4"rx2h" space, and the part fits on the printer well, but the part bottoms are far from flat. This becomes an issue as the sides are also not flat, and the ‘skirt’ on the sides is not all that round, has fracture lines in it, and cannot be clamped in a lathe and machined well because of the glass-like nature of the HT resin.

We have a printer that can make the shape perfectly, an Objet 30 Pro, but it’s HT material has an HDT of ~60C (which is laughable that they call it HT), vs the Formlabs resin which can actually be used for the IM runs.

Basically what I am asking is, does anyone have experience with form 1+ vs form 2 and trying to make engineering parts? Are tolerances and flatness, any better? Does the peel mechanism put less stress on the supports and cause fewer fracture lines? AKA, should we buy a form 2 to try and make these parts, or is there little chance that it would be able to fix most of our issues from the form 1+?

Thank you!


It can print flat parts just fine if you get the orientation well and have the supports arranged to keep things stable. But–thin flat parts can very often warp during curing. This is from the standard resins. I did to a pretty good flat print recently that’s a little over 1"x1" and it came out fine, but I’ve had others that warp after curing.

Have you ever done anything larger? We can do small prints on the 1X1 scale with little to no issues. My issues have come in on larger parts, such as 4" r x.375" thick, and have flatness issues that are much worse than .025". I would really like to maintain flatness of <0.01" if possible, especially since the HT material has a very low elongation at break, and I need to put the part inside of a precision machined housing to hold the male and female plugs (both printed) to then put them in the injection mold machine. Total Shot will be ~ 1.8oz of a 20MI LLDPE.

If you’re printing molds then you’d probably need to make the walls thicker, may require the larger build area of the Form 2 if you want to keep using 3D printers.
You might need to use a CNC machine, I don’t think these types of printers are good for long flat parts.

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