Hey there @Olivier_Suire,
Thanks so much for taking the time to post! I absolutely understand your frustrations regarding not being able to completely empty a cartridge via the printer’s normal dispense.
To be perfectly open about things, this is a really difficult feature for us to implement safely. The specific reason for this difficulty is that we don’t have a way to make sure the cartridge is actually empty when a user hits “empty completely” or whatever the option would be called. At this point, we prefer to keep a human in the loop. At HQ, we empty the last remnants of resin from a cartridge directly into a resin tank, and that way you’ll know that you’ve gotten all the material you can out of it.
As long as the resin level isn’t significantly above the upper fill line you should be totally safe to pour it in, insert a new cartridge and then start your print. The printer will sense the level of the resin right at the beginning and it will know that it doesn’t have to dispense more resin until the level drops a bit due to the material being used.
Alternatively, if this method makes you nervous, Sculptingman above me suggested switching to open mode just to finish that cartridge off, which is a perfectly good option as well.
We understand that this isn’t an ideal answer to your concerns, and we’re certainly going to keep investigating potential adjustments. Thanks so much again for the feedback.