MIL Extrusion 3D Printers SOP


Standard Operating Procedure

Safety: Keep hands, hair and articles of clothing away from the printers when operating. Be aware that the extruders are very hot. Keep flammable materials away from the printers.

  1. Design the piece you want to print in your choice of CAD software.
    1. Keep in mind that overhangs will be problematic. The printer cannot extrude a long platform that hands over nothing. If you have a subtle slope up to an overhang, they may be workable, however. This is not an issue on the uPrint printer which uses support material.
    2. Use as little material as possible in your designs.
    3. When you are finished, you will need to export your work as an STL file.
  2. Assure the print platform is clear of printed items or debris.
  3. Email your STL file to the printer’s computer at or transfer it to the computer on a flash drive.
  4. Open the printer software (uPrint or FlashForge) and drag your STL file into the software window.
  5. For the uPrint
    1. Follow the software instructions in the accompanying manual.
    2. Safety:
      1. The interior of the printer may become very hot; use gloves to manipulate the heated interior.
      2. Be sure to empty the bin that holds extrusion material from clearing the tip; it’s the bin in the back left of the interior of the uPrint. If this becomes full it becomes a fire hazard.
  6. For FlashForge printers.
    1. If you can print in PLA, please do so. ABS tends to clog the extruder.
    2. Assure you have enough material, and see the printer’s manual to relod material if needs be.
    3. Assure the bed is covered by a flat layer of Kapton tape.
    4. Position your piece on the virtual platform in the software, ensuring it’s positioned to avoid overhanging material.
    5. Select the correct extruder in the software (Note: the “right” extruder refers to the extruder to your right if looking at the printer)
    6. Insert a flash card into the computer.
    7. Press the “Print” button in the software.
    8. Make sure you select the standard PLA (or, if needs be, ABS) options in the print settings. If you are unsure on the many settings, consult the lab manager.
    9. When you finalize the settings the software will save the file needed by the printer. Save this file to the SD card.
    10. Put the care in the printer (just inside the printer).
    11. Select “Print from SD” and it will give you an error everytime. Just select “Print from SD” again.
    12. Select the file you wish to print, and the startup sequence should begin.
  7. Wait and observe at least the first couple layers of the print to make sure it does what you expect it to do.
  8. You do not need to continually pay attention to the printer but every 10 to 15 min someone should be there to check on the print, otherwise a lot of material may be wasted or hazard may be created if the printed material detaches from the base.
  9. Do not print items overnight, when no one can check in.
  10. Once your print is completed:
    1. uPrint:
      1. Remove the platform while wearing gloves to protect you from the temperatures in the printer.
      2. Remove your piece from the platform. You may need a spatula to detach your piece.
      3. Turn on the caustic bath (which will dissolve your support material),
      4. Wearing gloves and safety glasses, place your piece into the caustic bath.
      5. Depending upon the amount of support it may take from a couple hours to overnight to fully dissolve the support material.
      6. Wearing gloves and safety glasses, remove your piece from the caustic bath and place it immediately into a plastic bin, making sure not to drip on the counter or floor.
      7. Take the bin to a sink and thoroughly rinse off your piece and let it soak in water for at least an hour.
    2. FlashForge:
      1. Use the spatula to remove your piece, being careful to not touch the hot platform or tear the kapton tape.
      2. Clean off the platform and interior of the printer of stray material. If the tape is damaged, replace it for the next user.