SSW - Washing and Postcuring (Resin Printing)

During this process you will be working with isopropyl alcohol and 3D printing resin. Review the COSHH overview pages for these materials before starting work.

Cleanliness

Resin printing is messy - it is your responsibility to leave the resin printing area clean for the next person even if it wasn't you who made the mess. Make sure that all nitrile gloves are thrown away safely, surfaces are clean and free from resin residue, and tools are clean. Leaving hazardous resin on surfaces makes the space unsafe for other users.

Personal Protective Equipment

Nitrile Gloves You must wear nitrile gloves when working with the printing resin or isopropyl alcohol.

Safety Glasses You must safety glasses when working with the printing resin or alcohol cleaning bath.

Specific risks you should be aware of

Extremely Flammable Isopropyl alcohol is flammable. Keep away from naked flames. Keep the lid on the alcohol container at all times. Secure the lid when it is on the container and mop up spills immediately.

UV Radiation The post-curing process uses UV light. Ensure the cover for the post-cure station is in place before starting the post-cure process.

Hazardous Fumes Only perform post-processing tasks in the Print Hive, this has built in ventilation.

Washing parts

Parts are washed in a bath of isopropyl alcohol. It is important that the lid of the alcohol container is returned immediately and the lid clips are fastened securely.

Do not leave the lid on the container without fastening all the clips.

• Put on nitrile gloves and safety glasses.
• Check the wash station is not running a cycle. If it is, wait until it is finished.
• Remove the lid of the alcohol container, remove the mesh basket and shake it lightly to remove excess fluid. Place it to one side.
• Replace the lid of the alcohol container and secure the clips.
• Place your parts into the mesh basket, ideally sitting independently at the bottom. Parts should still have their supports still attached, and will be shiny from the excess resin.
• Remove the lid of the alcohol container, gently place the mesh basket with your parts into the alcohol. Ensure the level of the alcohol does not exceed the 4 litre mark on the side of the container.
• Replace the lid, secure the clips.
• Using the buttons on the front of the wash station, select "wash".
• Rotate the dial to set the time the wash cycle will run for.
  • Small parts - 5 minutes. Slightly longer if there are complex geometries.
  • Large parts - 15 minutes or longer.
• Press the knob to start the wash cycle.
• Clean the work area with paper towels and a small amount of isopropyl alcohol. Ensure there is no resin left on work surfaces and all paper towels and gloves are placed in the bin.

You can now go and do something else until the wash cycle has finished. Set a reminder alarm on your phone so you remember to come back and get your parts out of the wash!

Removing parts from the wash

• Put on nitrile gloves and safety glasses.
• Check the wash station is not running a cycle. If it is, wait until it is finished.
• Remove the lid of the alcohol container and remove the mesh basket.
• Let the excess alcohol drain off, then place it to one side.
• Replace the lid of the alcohol container and secure the clips.
• Carefully remove your parts from the basket and place them on the mat.
• Return the mesh basket to the alcohol container and replace the lid, securing the clips.
• Wait for the alcohol to evaporate from your parts.

Properly washed parts will have a matte look once they are dry - if there are shiny sections of resin left after the alcohol has evaporated you should wash them again. Alcohol will be wet like water when touched with a gloved finger, resin will be sticky. Excess resin will reduce the effectiveness of the post-curing and will reduce the accuracy of your parts so it needs to be removed completely.

Removing supports and post-curing parts

Once your parts have been completely washed and are dry you can post-cure them in the curing station. This finalises the curing of the resin and makes for resilient, finished parts that can safely be handled without gloves. Before post-curing you should remove the support material.

• Put on nitrile gloves and safety glasses.
• Remove support material gently. You can use the red-handled snips to cut stubborn supports.
• If the part is sturdy and not thin and spindly gently application of heat can help the delicate support structures detach cleanly.
• Place all removed supports in the bin.

Make sure you remove all your support material before post curing - once the part is fully cured you may find you cause damage when trying to remove supports.

• Check the cure station is not running a cycle. If it is, wait until it is finished.
• Remove the lid from the cure station and set it to one side.
• Place your parts on the clear turntable. Space them out as much as you can to reduce the amount of shadowing.
• Large parts or those with unusual geometry may need the flexible spotlight to reach all areas.
• Replace the lid.
• Press the Cure button on the front control panel.
• Rotate the knob to set the time for the cure cycle.
  • Small parts: 5-10 minutes
  • Large parts: 10 minutes+
• Press the knob to start the curing cycle. If you are using the flexible spotlight you should turn this on using the Flexicure button.
• You may need to run a couple of shorter cycles, turning the part in between, to ensure you get full coverage with the UV light.

When the cycle is finished you can remove your parts. You should wear gloves while interacting with the machines and covers, but now the parts are cured there is no need to wear gloves to handle them.