Special Considerations for Rigid 140C Black Material

Figure 4® Rigid 140C Black requires special mixing instructions to help ensure that your parts possess the expected mechanical properties.

Mixing Instructions

The material is provided in two bottles, labeled "Part A" for the resin and "Part B" for the catalyst.

Select an appropriately-sized polypropylene bottle/container for material mixing. Other types of containers may be used, as long as the container is non-reactive.
The same mixing bottle may be used for every Rigid 140C Black build, as long as:

1. The bottle is used every day to mix material

OR

2. If the bottle will not be used for an extended time, it should be thoroughly cleaned with >90% alcohol before it is stored.

Mix Ratio

Standard batch - 95g of Part A to 5g of Part B

For other batch sizes, ensure the mass ratio is 19 to 1.

Mixing Technique

1. Place the mixing container on a scale and zero out the scale. Pour 95 parts of Part A in the mixing bottle. Pour five parts of Part B in the mixing bottle.


Fill mixing bottle with 95 parts of part A material.
Fill mixing bottle with 95 parts of part A material.
2. Close your mixing bottle and shake up and down vigorously for two minutes.

Resin Tray Loading Instructions

1. To ensure you get the maximum amount of mixed material out of the bottle:

  • Place the print platform on the elevator arms.
  • Gradually pour the mixed material into the resin tray from above.
  • Allow the mixing bottle to sit inverted on the print platform until material stops dripping out of the bottle.

2. Inspect the resin tray film to make sure there are no bubbles (bubbles are unlikely if stirred carefully).

NOTE: If bubbles are present, wait 20-30 minutes for them to settle away from the film.

3. Begin your build.

General Usage

  1. Always start with a clean resin tray and freshly mixed material. As a two-part material, the service life of the mixture is limited to no more than 24 hours.
  2. Cues that material should be discarded and replaced with fresh material are:
  • Reduced green strength (strength of part before post curing). This may result in weak or detached supports.
  • Soft parts. Low green strength also results in soft parts in the green state. At the extreme, parts are rubbery.
 

Post Processing

Safety

Be sure to follow all safety instructions outlined in this guide, and particularly Material Handling and Safety.

Recommended solvents

  • Tripropylene Glycol Methyl Ether (TPM) or PolyFlush
  • >90% Isopropyl alcohol (IPA)

NOTE: Cleaning with solvents should be conducted in a ventilation hood with proper PPE.

 
Solvent saturation

  • TPM should be replaced when cloudy. To extend the life of the solvent, you can filter some resin with cheesecloth or other fine filter media. Discard waste resin according to local government regulations.
  • IPA should be replaced when cloudy, or when green parts remain sticky after second rinse. Decant the top of the IPA into a fresh container and discard the residue at the bottom of the container according to local government regulations.

Cleaning parts manually
Ultrasonication is not recommended for cleaning parts printed with this material. Instead, clean the parts as in the section Clean Parts Manually, but using the following specific instructions.

  1. Fill your dirty container with TPM
  2. Shake the covered TPM container with your parts for five minutes.
  3. Flush parts with IPA for one to two minutes, ensuring that all TPM residue is gone. Make sure to remove resin from holes, corners of parts, and other areas where the uncured resin might not fall away easily. You may need to use swabs, small tools, and low-pressure compressed air to remove resin from tight areas of parts. Use a soft brush to remove any areas of white precipitation caused by the reaction of IPA with the uncured resin.
  4. Dry your parts and remove supports as seen in the section Dry the Build Parts. For this material specifically, dry for 25 minutes at 35°C (95°F) for at least one hour. Your parts must be completely dry before being post cured.
 
UV Post Curing
For this material, both UV and thermal post curing are required to achieve full curing and desired mechanical properties.

  1. Place the part in the LC-3DPrint Box for 90 minutes.

    TIP: Hanging the part in the center of the cure unit provides the best results.
    TIP: For flat parts that may have a tendency to curl, raise glass plate a quarter to halfway up in the curing unit for a more even cure. You can do this by using glass jars to prop up the glass plate.

  2. After curing, let parts cool down until they reach ambient temperature to avoid dimensional inconsistencies.

Thermal Post Curing Steps

  1. Place the part(s) in a thermal oven and start a temperature ramp-up to 130°C (266°F) (ramp up rate of 3 minutes to reach temperature, minimum) and hold that temperature for 3 hours to fully cure parts. If you do not have a thermal curing oven, please bear these temperature requirements in mind when purchasing one.
    TIP: Place parts on center rack for best results and an even thermal cure of your part(s).
  2. After post curing time has passed, let parts cool down until they reach ambient temperature in order to avoid dimensional inconsistencies.