Each Form 3 resin cartridge tracks the amount of resin remaining on the ID chip located near its bite valve. During a print, Form 3 generation printers regularly update this value based on PreForm’s initial estimate of the amount of resin required to print the current job.

Every few layers, the printer subtracts the amount of resin that has been used from the current total stored on the cartridge. This does not directly account for dispensed resin, either before or during the print, but knowing how much resin has been consumed helps estimate how much needs to be dispensed to refill the resin tank.

Any issues with this estimate can lead to inaccurate cartridge fullness tracking. For example, the printer may report that the cartridge is low when it is not, or that the cartridge is fuller than it actually is.

If your Form 3 generation printer is reporting the wrong amount of resin in a resin cartridge:

1. Update PreForm and your printer’s firmware so you have access to the improvements to the resin tracking algorithms.
2. Avoid manually pouring resin into the resin tank, as this can make the fullness tracking inaccurate.

If necessary, you can estimate the fullness of a resin cartridge based on its weight:

• An empty resin cartridge weighs approximately 290 g.
• Liquid resin has a density of approximately 1.1 g/mL, although this varies depending on the resin type.
• Most Formlabs resin cartridges contain 1 L of liquid resin, so a full cartridge weighs approximately 1,390 g.

For example, if a resin cartridge weighs 830 g, subtracting the weight of the cartridge itself leaves 540 g of liquid resin. At 1.1 g/mL, this means there is approximately 491 mL of liquid resin remaining in the cartridge and it is 49% full.

If your printer continues to report incorrect resin cartridge fullness, upload the latest logs from the machine before contacting Formlabs Support or your authorized reseller.