3D Printing

General Instructions

  • Book a training here <add link here> before using the 3D printers.
  • Maximum of 3 hour prints during the day, 6 hours at night.
  • Leave names and print time on the tags.
  • Watch the print for the ENTIRE first layer to make sure everything is running properly.

Health and Safety

For your safety please keep your fingers away from the printer while it is printing/starting a print. While the nozzle will get really hot and the bed will get warm, the biggest risk is getting your clothing, hair, or fingers caught in the moving parts.

Machines

UltiMaker S3, S5
Ultimaker S3, S5

These printers are a bit harder to work with as they have many sensors that sometimes get tripped by the smallest error. However, this means they need much less calibration than the Prusa printers. But they work like any other FDM printer.

Prusa
Prusa

These are our most popular printers by far. They work like any other FDM printer but require a bit of calibration at the beginning of every print.

  • Calibrate Z-offset before every print.
    • *note: it can be helpful to add a Skirt (recommended for every print) or Brim (recommended to specifically help print/bed adhesion – explained below under recommended Cura settings) in your Cura settings to give you a chance to calibrate the nozzle distance from the bed before your model starts printing.
Example of Z-offsets from too high -> perfect -> too low
Example of ideal Z-offset.
Creality
Creality Belt

The Creality Belt is special because it has an “infinite Z axis”.

This printer uses a special slicing software called Creality Slicer (Creality’s version of Cura). Make sure to set the printer profile to Creality 3DPrintMill.

This 3D printer prints at a 45° angle which makes overhangs a problem of the past. This does mean, however, that you have to be mindful of the orientation of your model when printing it and the direction of overhangs/layer lines when designing it (shown below).

example of important orientation of models on Creality Belt printer.
This picture shows the same model printed in the correct orientation on the top and the wrong orientation on the bottom. As you can see, the top model prints perfectly with no supports while the bottom one needs supports to print properly.

Materials and Softwares

Material: PLA

Recommended Cura settings:

  • Nozzle Temp: 200°C
  • Bed Temp: 60°C
  • Travel Speed: 30-40 mm/s
    • You can always turn this up after the first layer but if your speed is much faster in the first layer the chances that your print will fail are much higher.
  • Layer Height: 0.2mm
    • Larger layer heights reduce print time but smaller layer heights create fewer steps in the layering process leading to higher-quality prints. 0.2mm is recommended for the prototyping phase while 0.1mm is recommended for the final product (but this will double the print time so keep that in mind).
  • Wall Thickness: 0.8mm
    • This number should always be a multiple of 0.4 as that is the diameter of the nozzles installed on all our printers. 0.8mm means the walls are 2 layer lines thick.
  • Top/Bottom Thickness: 0.8mm (same as walls)
  • Retraction: Enabled
    • Retraction Speed: 35mm/s
  • Cooling: Enabled
  • Support: Enabled (if your model has overhangs larger than 45° – These will be highlighted in red when you import your model into Cura)
  • Build Plate Adhesion: Skirt
    • A Brim or Raft is recommended if your model doesn’t have a lot of surface area touching the build plate (the print bed).
      • Rafts are pretty hardcore, they print an entire plastic biscuit for the model to be printed on to help with adhesion. Meanwhile, Brims just add a bit of width to each area of your model touching the build plate.
CAD (computer aided design) tips for 3D printing. 1. Make wall thickness a multiple of your nozzle size (we use 0.4mm diameter nozzles so you could do wall thicknesses of 0.8mm, 1.2mm, 1.6mm, etc.) 2. Avoid steep overhangs to reduce the need for supports 3. Vertical holes print fine, but horizontal ones should be tear-drop shaped to mitigate steep overhangs. 4. Pointed arches are better than round ones for this same reason. 5. Vertical edge fillets increase print quality by allowing the printhead to sweep around them. *note: any fillet smaller than the nozzle thickness won't be able to print. 6. Roughly 0.2-0.3mm clearance should be added between fitted parts. *note: the smaller the clearance the tighter the fit. 7. Adding a fillet or chamfer between a wall and base strengthens the join by adding more interface. 8. Fillets don't work well from below, due to harsh overhangs. But they can look great in other areas. 9. Equal chamfers always work (even from below) as their overhand remains at a printable 45°. 10. Combining fillets and chamfers mitigates the issues of fillets alone and smooths the chamfer. 11. Using parameters and constraints allows you to easily edit and iterate upon your designs. 12. Printers can bridge gaps between bodies quite easily. Distance varies, but most can easily handle 2cm+. 13. A thin, sacrificial bridging layer can reduce the need for support material. It is cut away after printing. 14. Triangles can be staggered under a large roof, to enable larger distances to be bridged. 15. Sacrificial, perpendicular ribs can be added to support overhangs during printing. 16. Curves look good with an axis in the Z direction, but due to the layering process can look very poor in the X/Y. 17. A slit, bolt and trapped nut can be added to holes to allow them to be tightened around another part. 18. Compliance can be added to parts to enable flex, which enables push-fitting parts. 19. Reduce the risk of a print warping up from the bed by rounding out or adding mouse ears to corners. 20. Concentric slits can be cut from the base of a model to about 10mm up to prevent warping. 21. Use software that makes manifold objects (without tiny gaps and reversed or overlapping faces), to avoid slicing errors. 22. Complicated or fitted parts of an overall print can be isolated and printed to test for fit. 23. Diagonal ribs can be added to support/enable a roof to bridge between them. Can be beneficial inside a model. 24. Text looks best when indented into a vertical surface. It reduces overhangs and has better resolution. 25. Due to the planar layering of most 3D printers, print orientation has a significant impact on the parts strength.
3D design tips for 3D printing by Billie Ruben

Resources

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