Printing directly on build platform

I have an object that has very precise teeth that need to fit with matching teeth on a second object and they occurs on top & bottom of each object.  I have tried various orientations with limited success.  I have also split the object in half to have a flat base on one side.  I have tried then printing the object with this flat base attached directly to build platform.  This did give me a flat base but with voids and the teeth were very precise.  Whenever I print with supports the attachments always create imperfections and in some cases warpage that does not give me the precision I need. I am thinking of trying printing with the teeth adhered directly to the build platform but this would mean having some portions of the model unsupported for a small distance.  Does anyone know how large and area can be unsupported before  distortion starts to occur?  Also does anyone have experience printing directly on the build platform without have these voids occur ,  what causes the voids to occur and is there anything one can do to the model to not have the voids occur?  Thanks in advance for any help or advice.

You will never get precise fit with this kind of 3d printing technology.  No matter if it’s on a Form1 or a much more expensive SLA machine.

The reason being is that when the resin cures, it expands, shrinks, warps, stretches, moves, etc. You can print the same part over and over and every time it will be slightly different.

If you need mechanical precision parts, I would recommend looking into different 3d printing technology. Something that costs A LOT MORE MONEY.

You’re talking about printing teeth down?  You’ll have a lot of trouble with this, as the Form compresses the first several layers to allow for some misalignment between the tank and the build platform.

Make sure there are no bottoms parallel with the build platform (top when on the printer.)  10-15 degree angle is usually good enough.  Also, make sure the area you’re printing in is at least room temp (68+.)  I get a lot of extra goop where  the supports meet the part if I’m printing in a cool room.