Moai SLA Printer Manual

Notes and instructions for our Moai SLA Printer

THIS PRINTER IS ONLY TO BE USED BY STAFF

Reasons

  • liquid resin is much nastier, both in terms of safety and to manage, than FDM filament. This includes the required post process clean up with IPA and UV curing
  • resin is expensive
  • the vat (print bed) is a consumable and relatively easy to damage
  • models have to be carefully modified or designed and oriented for SLA
    • they should be hollowed to save resin and the VAT
    • suction is created peeling each layer, so…
    • flat areas should be printed at an angle to reduce surface area and the suction pressure
    • drain holes are needed to allow unused resin to escape
    • internal baffles and drain holes may be needed to control how resin flows around the object as it’s printing.
  • it uses a laser powerful enough to damage vision

Resources

General

Regular Maintenance

Software

Resin Guides

NOTE Laser turns on when you adjust it in settings- so remove the tank BEFORE adjusting the power level! (reference)

Known Issues

Current Configuration

Printing Process

Cleanliness is really important for successful prints and our safety.

The resins are very viscous and sticky- they will get everywhere if care is not taken.

1. Model Preparation

Models need to be adjusted so that they

  • are hollow (to save resin, to reduce “Peel pressure” and not damage the vat)
  • have drain/pressure relief holes (so resin isn’t trapped afterwards, and to reduce suction during layer peels)
  • possible tools: CAD (Fusion360, Solidworks, Onshape…), Modelling (blender, Maya, sculptress, 3DCoat,…), Meshmixer, Asura

2. Bed Preparation

  • object needs to be oriented to reduce each layers surface area
  • supports need to be added
  • possible tools: Asura, Noble, XYZ, Meshmixer

3. Slicing

  • use Moai version of Cura
  • make sure “Custom” is selected for profile
  • use biggest layer height reasonable for your goals; more layers => more vat wear
  • red part of print bed in Cura moves the most when peeling
  • look at, and mark the “last print location” sheet on/by the printer. Must move prints around to maximize tank life!
  • export G-Code to g-code folder on SD card
    • do not delete g-code files on SD card (see SD card issues above)
  • eject the SD card in Windows, don’t just pull it!!!
    • SLA g-code files are VERY large. Windows buffers the writes; Cura will say it’s done, but windows will still be streaming the file to the SD card.

4. Print

  • check the resin tank is in place and has enough resin
  • make sure bed is in place, and holding nut is just-tight
  • close the door
  • select the file and start the print

5. Post Processing

  • wear gloves and eye protection!
  • when print is done, remove bed from gantry and put it on the drip stand (red bracket at side of vat) for at least 10-15 minutes. This saves a lot of resin and makes for easier cleaning of your print.
  • turn on the fan for the fume cabinet
  • get clean water for rinse jar
  • alternate 3 times rinsing in IPA and then water, 30 seconds each
  • get clean water for curing
  • carefully remove part from print bed
    • use razor scraper, long scrape
    • use a low angle (parallel to print bed surface)
    • approach from multiple directions
    • can nip supports get object, then remove supports from print bed
    • supports can break off and pop/fly off print bed; please find and clean up where they land!
  • use the spray bottle of IPA and paper towels to clean off the print bed, print bed handle, scrapers, and any other surface that resin has got on
  • dunk print in water for curing (to exclude atmospheric oxygen which inhibits curing)
  • surround with mirrors
  • setup UV lamp
  • cure with UV light for ~30 minutes. Rotate object occasionally
  • cut, don’t break, supports for best results

First draining/filtering of vat.

A few remnant pieces and some very thick, partially cured globs.

PDMS layer looks ok. Used squeegee to carefully get the last resin drips.

Was messy and resin takes quite a lot of time to dribble out. So printing vat draining stand from thingiverse.

Care needed when refilling vat.

Found resin on tray holder, outside of vat, and inside bracket that holds bed to gantry!