UV Post-cure

Even though the parts are cleaned they are still considered green.  They need to be post-cured for handling and achieving the desired mechanical properties.

Notes about the UV post-cure process:

  • There are several post-cure options depending upon part size 

  • The largest parts in the largest oven will require longer cycle times to achieve mechanical properties

  • The optimal post cure temperature in the UV chamber is 65-75C. 

  • Make sure the UVA/UVV output of the chamber is enough to properly cure the parts.  Replace the bulbs as needed. 

    • Using a UV power accumulation meter can help aide in this determination. 

    • Using the EIT UV Power Puck II, a ProCure 750, for example, with new bulbs emits ~16 mJ/cm^2 per minute of UVA and 214 mJ/cm^2 per minute of UVV light. 

    • Any values less than 50% of these values will not properly cure the parts.

Using the Procure 350/ 750 UV chamber

  • To reduce part warpage, cure the parts while they are still attached to the support and build plate.

  • Cure for 180 minutes with down surfaces facing upward to allow UV light to get to the bottom surfaces of the parts.

  • Certain geometries may require flipping at the 90min interval to ensure even cure times and may require adjustment based on UV intensity emitted from older bulb.

  • Larger parts may require longer post cure times. Increasing in 60min intervals is recommended.

TIP: If equipped, close the vent/exhaust exit of the oven up to 90% closed to reduce air flow going out of the chamber while post curing. Doing so, elevates chamber temperatures improves mechanical properties.

Using the NextDent™ LC-3DPrint Box UV chamber

Note: The elevated temperature generated by the cure process in the LC-3D Cure unit (~75C). Best performance in mechanical properties has been achieved. 

  1. Cure for 90 minutes

  2. To reduce part warpage, cure the parts while they are still attached to the supports and build plate.

  3. After 90 minutes raise the chamber lid and allow parts to cool for 15 minutes.   This helps prevent warp in the higher temperature cure unit.

  4. Flip the part and cure for an additional 90 minutes.

  5. Allow the part to cool to ambient temperature before removing from the UV chamber to avoid dimensional inconsistencies.

TIP: Using standoffs to raise the glass bottom ~75mm from the bottom bulbs helps to reduce curling effects during post curing.

Flipping parts is not required if the unit is equipped with a glass bed.