Minimum resin level indicator korrect? - keep at least 25% before starting a print, independent how small it is?

I alwas was unsure of about how much resin I should fill in the tank. From what I remember, Formlabs says that the resin level should be within MAX and MIN marks of the tray. ok.

But the MIN mark - in my opinion - is not a MIN mark, it is the bottom of the tank, or even a little bit lower. I have ordered a spare resin tank, and will investigate then whre the MIN mark level really sits.

That said, I always thought that I do not need to refill the tank to maximum before every print, when I do very small ones.

But see the attached photos.

I started a print where preform said it will take 4ml - so very very small. At this time, the resin level was somewhere between 1/3rd, I do not remember exactly. But nothing to worry for a 4ml print.

At the end of the print, when I came to the machine, I was frightened because the resin has “pulled away from the left side of the tank” leaving a large area blank (uncovered with resin), and this area becoming bigger and moving towards the building platform. But at this time, the resin level indicator (see photo) was maybe at about 25% over MIN - so normally nothing you would worry?

So based on a comment, where someone got the information from formlabs that the resin can be stored “very long” in the tray in the printer, this would mean that it is best to do so and never let the level go down to lower than +25% ?

Did anybody have the same experience?

Will open a support ticket and ask formlabs what they think about it.

YES, I have checked with the level - my printer stands even on a flat ground.

Hi Martin,

There is no minimum fill line for the resin tank. The lower line is there to help you locate the bottom of the tank. Best,


Hi Craig,

thanks. Just a bit of additional informaton: The lower line is NOT the bottom of the tank, it is BELOW the bottom, below the silicone… See attached photo, where the resin tray is absolutely empty in this area.

So it is very important to know NOT to trust the bottom line (resin is left, continuing printing …) but instead trusting the MAX line.

I learned from Jennifer that the tray holds about 200ml, but can not print down / be emtied to “zero” as resin starts to pull away from the sides and leaving certain areas of the building platform uncovered. So Jennifers suggestion was: when the calculation of preform is for a print > 100ml, resin tray should be filled up mid-print. From my experience, this still leaves some reserve.

If I accidentally/absentmindedly fill the resin tank approximately 8-9mm too high will this be an issue?