Additive manufacturing in plastic.

3D Printer

  • ‘Additive manufacturing’, like Lego
  • Process: FDM (Fused Deposition Modelling: i.e. hot, layers)
  • Materials: PLA, ABS, TPU, Nylon, PET
  • Our machine: Creality CR-10 (affordable, Arduino-powered, classic Cartesian design)

Safety

  • Materials: only PLA (no fumes)
  • Heat: hot end approx 200°C, bed approx 40–70°C
  • Motors: keep your fingers out of the way
  • Unattended prints: prints go wrong; you must be in the room and keep an eye on the printer.

Constraints / Design rules

  • Print volume: your model must fit!
  • Print time: expect 1 – 60 hours
  • Printing layer by layer: think about overhangs and support (consider rotating model)
  • Resolution
  • Aesthetic limitations
  • Mechanical weakness
  • Material vulnerabilities (heat, moisture, light)

Anti-constraints (or new abilities):

  • Pre-assembled parts / mechanisms
  • Programmatic customisation
  • Affordable one-offs (no tooling)

  • Novel modes enable new kinds of making: e.g. vase mode

  • Follow some simple design rules

Workflow

1. CAD

Design your 3D model and save as an .STL file

Software:

  • Fusion 360
  • Solidworks

Or download a model as STL (e.g. Thingiverse)

2. Slice

  • ‘Slice’ the model into layers to generate tools paths.
  • Configure settings for your printer and model
  • Inspect the preview and adjust the ‘printing strategy’ (Here’s a video showing how to view the layers and toolpath in Cura.)
  • Save file as .GCODE onto SD card

Software:

3. Print

  • Load filament into printer
  • Check bed
  • Print file from SD card
  • Monitor while printing, especially first few layers. Be careful of tall models with overhangs

4. (Repeat)

  • What worked, what didn’t?
  • Do you need to change your design, or just your print settings?

5. Finishing / Assembly

  • Often much easier to print a model in 2 parts and assemble
  • Surface finishing (more with ABS)
  • Bodging

Some typical print settings in Cura

cura1.png

Basics: model orientation, print quality preset, temperature, support, adhesion.

cura2.png

Note build plate adhesion and supports for overhangs.

Assignment

Print a pre-designed 3D object (e.g. from Thingiverse).

What do I need to do to pass? (40%)

  • Demonstrate safe use of the 3D printer.
  • Consider how your choice of model affects print time and difficulty
  • Choose appropriate slicing settings that are likely to result in a successful print
  • Document your choices, settings and result and reflact on what you did and how it could be improved

Extra credit (50-100%)

  • Try printing a model you have designed.
  • Experiment with different slicer settings, and document the effect on the model
  • Try printing a torture test model
  • Experiment with vase mode
  • Try making a model that breaks one or more of the design rules and see how it prints
  • Try printing a model with functional, interacting or mechanical parts
  • Try making a part that interacts with parts made on the laser cutter

Prep for next week