PU Rigid 650 Resin and PU Rigid 1000 Resin have unique printing and post-processing requirements compared to other Formlabs resins. Please read through this Quick Start Guide before attempting to print.

Resin safety

To safely handle resin, follow Formlabs general safety and handling recommendations and read and understand the safety data sheet (SDS) available at formlabs.com/materials/#data-sheets.

Shelf life and pot life

The shelf life of the resin in an unopened aluminum bottle is 18 months from the date the resin was manufactured. After opening the bottle, the resin’s shelf life is reduced to about one month.

PU Rigid 650 Resin and PU Rigid 1000 Resin are sensitive to moisture. Upon exposure to moisture during printing and storing, the resins start to cure, and their viscosities increase until printing becomes nonviable. The period when the resin viscosity is within a viable printing range is called “pot life.” Elevated humidity and temperature will reduce the resin’s pot life.

1. Place your printer in a dry cabinet and level the printer.
   • On a Form 2, tap the printer icon on the home screen. The Your Printer screen appears. Tap Settings > Printer Leveling.
   • On a Formlabs LFS printer (Form 3 or later), tap the printer icon on the Home screen. Tap Settings > Maintenance > Printer Leveling.
2. Set the humidity to the lowest setting in the dry chamber.

The thickness of your part affects post-curing times and is described in the Support Removal and Post-Curing section. Refer to the PU Rigid Resin part design guide available at formlabs.com/pu-resin-support for suggestions about how to design parts printed with PU resins.

1. Download the latest version of PreForm from formlabs.com/software.
2. Open the STL/OBJ/3MF file in PreForm and orient the part according to Formlabs guidelines.
3. Both PU resins strongly adhere to the build platform. We recommend printing all parts on supports to make removal from the build platform easier and to reduce accidental damage to the part during removal.

1. Select your printer, material, and layer thickness, then choose the option labeled Automatic filling.
2. Send the file to the printer.
3. Shake the aluminum bottle of PU Rigid 650 Resin or PU Rigid 1000 Resin to ensure it is thoroughly mixed.
4. Unscrew the vent cap at the top of the cartridge. Use the funnel included in the resin kit to pour resin from the bottle into the empty cartridge.
5. Screw the vent cap back onto the top of the cartridge. The resin’s pot life in the cartridge ranges from seven days to four weeks, depending on ambient humidity and temperature outside the cartridge.
6. Insert the cartridge, tank, and build platform in the printer.
7. Start your print.

1. Fill your Form Wash or Form Wash L with fresh Propylene Glycol Diacetate (PGDA).
2. Insert the build platform with printed parts still attached into the Form Wash or Form Wash L.
3. Set the Form Wash or Form Wash L to 2 minutes and wash the parts.
4. After washing, blow the PGDA solvent off the parts using compressed air directed away from you.
5. Repeat steps 2, 3, and 4 until parts are clean from excess resin. To check, gently touch the parts with one of your fingers while wearing nitrile gloves and ensure there is no residual resin sticking to the gloves.

1. Carefully slide a removal tool under the beveled edge of the base and slowly peel to separate the parts from the build platform. Clean excess uncured resin from the build platform with a spray bottle of PGDA or IPA.
2. Optional: Loose parts can be dipped in an n-Butyl acetate bath for no more than 15 seconds to speed up the PGDA evaporation. Do not leave parts in n-Butyl acetate for more than 30 seconds, as this can cause part warpage. Do not use a Form Wash bucket for the n-Butyl acetate bath, as it has not been tested with high concentrations of the solvent. Use compressed air to blow excess n-butyl acetate off the parts.
3. Place parts on parchment paper or a similar non-stick surface in ambient conditions for at least 24 hours to allow all remaining PGDA to evaporate. The optional n-butyl acetate wash helps speed up the PGDA evaporation. Ensure parts are completely dry since residual PGDA and n-butyl acetate on parts can lead to a poor surface finish during the post-curing step.

We recommend post-curing most parts without supports. Supports are more difficult to remove if they are post-cured. However, some parts can warp during post-curing if they are not properly supported. Please refer to the PU Rigid Resin part design guide available at formlabs.com/pu-resin-support for more detailed information about part warping.

1. Carefully remove supports with a flush cutter.
2. Make sure your parts are completely dry before post-curing.
3. Set the humidity chamber to 46 °C and 70% relative humidity.
4. Place parts on clean parchment paper or a similar non-stick surface laid on the metal shelves in the humidity chamber. The non-stick surface prevents parts from sticking to the metal shelves.
5. Leave the parts in the chamber for the time listed in the table below to achieve optimal mechanical properties. Leaving parts in the humidity chamber for longer than the recommended time will not adversely affect them.

For additional information on printing with PU Rigid resins, tank cleaning and resin disposal, read Using PU Rigid 650 Resin and Using PU Rigid 1000 Resin, available at formlabs.com/pu-resin-support.

Continue to monitor your resin pot life. We recommend either changing the resin in the tank or mixing in fresh resin if the resin viscosity exceeds 2000 cPs. An easy and reliable way to check the resin viscosity is to use a Zahn cup #5 viscometer. Alternatively, submerge a blunt, flat object in the resin and drag it gently across the length of the tank. Do not use a sharp object or press it into the tank film to avoid damaging the resin tank. If the resin flows easily and fills in the gap left by the tool, the viscosity is low enough to continue printing.