Hi,
I just got form 1+ about 2 weeks, no issues so far and been loving this small printing monster. There is one print that I have been having some issues. I tried to print a puck-like object with some threading inside. And it creates some sort of “bubble” or “clustered” of resin at some part. Are there anyone having similar issues as me? Here are some photos and my settings for PreForm. Thanks!
Small bits of cured resin will cause that as well as bubbles, double check your resin and try to push the bubbles to the side. I mix what I have in the resin tray really really slowly with the scraper and it made a big difference in my prints.
The problem is most likely the air pocket formed by the lip of the lid where the lid is closest to the build platform. To see the problem area better move the slice view slider down until all you see is supports. Now slowly move the slider up till you start getting to the object. Move it up a little more and you will see an area where there is an unprinted area completely surrounded by printed material. Since this area does not have a hole letting the pressure equalize during the peel and return process the pressure blows one out of one of the printed walls this leaves a hole in your print and cured material floating around your tank.
The fix is to either orient your part to prevent this or put an extra hole in the part to allow for the pressure to regulate.
This problem could possibly be partially alleviated with slower peel and return speeds but Formlabs won’t give us control of that. It could also possibly be somewhat improved with over curing, however Formlabs won’t give us control over that especially not for only part of the print. It could also possibly be helped by using a different material from PDMS in the tray or doping the PDMS to make it less sticky. It could also possibly be improved with a different formulation of resin although I have not seen a good comparison study done of the Formlabs resins or third party resins to see how well they handle this kind of stress.
Not in this case. You would need 90° to fix it. This would of course differ on different models.
Thanks RocusHalbasch for the detailed explanation as I’ve been experiencing the exact same problems.
Now that I understand whats causing the bubbles / holes I can do something about it 
Nice one RH - I had this problem too, and re-orienting the parts to ensure no walled in air fixed it. Many thanks!
One outstanding point - the default butterfly clip that comes with the preform installation suffers this issue with Clear version 1 at 50 microns too!!