Form 3 Trying to Dispense Empty Cartridge

This is a problem that I think I will now post about monthly so it changes. Formlabs, please allow the user to tell the machine to not dispense resin or input ONE TIME that it is okay to continue with low resin. My Form 3 has been trying to fill the tank from an empty cartridge for 30 minutes now. I will continue to give updates until it starts.


I thought there is a weight sensor in the Form 3 to prevent this issue?

It is still trying to fill. My guess is that the Form 3 does not have the ability to start a print without filling, which is a capability of the Form 2.

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No- the Form 3 recognizes a new cartridge- and keeps an approximate tally of the volume of each print that uses that cartridge ( tho it can not account for waste from resin coating the part or build platform.

It Guesses- based upon this usage when your cartridge is running low and gives you an alert that you might want to order more resin- or at least check to ensure that you will have enough to finish the part.
These warning allow you to continue printing if you are sure there is enough resin to complete the print… or swap out for a full cartridge and continue the print.

The Form 2 can only tell a cartridge is empty when it tried to dispense resin, and the resin sensor detects no change in the level in the tank.

Unfortunately- it will not continue printing without you swapping out the cartridge. Even if you can plainly see the tank is full enough to finish the print without running below the lower fill line.

This is partly due to the fact that many resins are so viscous that the resin being even a little below the top fill line can compromise the ability of the resin to fully wet the printing surface after the wiper sweeps across, before the print is lowered into the tank- which could result in a messed up print-

Theoretically, they could have the resin sensor sense approximately how much resin there is above the lower fill line, and how much of the print volume is remaining to be printed- and give you the option to continue with the print if there is enough to finish-

However- it is likely more reliable to always have a next cartridge on hand and just swap out when this alert sounds- ( and not start a print that you don’t know you have more than enough to complete)

however- it should be noted that BECAUSE the Form 2 does not read a cartridge as ‘empty’ until it tries and yet can get none out of it- that you CAN add additional resin from a former cartridge to the one you are running, and it will keep running well after it has dispensed more than a liter.

Did you even see one of their webinars? They advertised that they added a real weight sensor.

It is not shown anywhere on the website anymore as far as I can see… so was this sensor part of the cause of the delay…?

Sorry- that is a typo- I meant to write Form 2- not Form 3-
I don’t know if the Form 3 works any differently- but that is how the Form 2 works.

I have heard the form 3 weighs the cartridge, but I don’t know how reliable that would be since the empty blow molded cartridges can vary by 20 grams in weight, so any measure would potentially be off by that amount.
But I have seen videos where it is claimed they ARE weighing the cartridge.

Did you ever get a resolution here?

Support says this is a known bug on Form 3 and will be updated with new firmware at some point. I again strongly strongly prefer that I only have to tell the printer once that my cartridge is empty and to continue to print, but at minimum be like the Form 2.

I print with low/empty cartridges for 4 reasons:

  1. Accidentally with a large print overnight when the cartridge runs out. It is soooo disappointing to come in the office after a 13 hour print and seeing this error message on the screen instead of my parts on the platform.
  2. Knowingly to get the final bits of resin out of a low cartridge. I could just dump it into another cartridge but this is easier.
  3. I screwed up and didn’t order extra resin! Yeah, my mistake but I am busy and tons of people use the printer so communication isn’t always perfect and someone is like “hey we are out of Rigid can you order more”. I’m like sure, but it won’t be here in 1 hr so you’re gunna have to print on an empty cartridge.
  4. Color printing. I’d rather mix small batches of various colors rather than a full liter. So I keep an empty color cartridge around in order to print the batches I made. This was the specific case prompting this post.
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This is incredibly annoying. My Form 3 showed up today and I loaded in my remaining Tough V5 to duplicate a print I’d finished with the Form 2 recently for comparison. There is plenty in the tank but the cartridge ran dry while filling. So my only tank is partially filled and my Form 3 is useless until I order more materials. What a bummer.