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3D Printing & CAD Modeling 101

Creative Technology Residency

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Last Class

  • Functions
  • Loops
  • Addressable LEDs
  • Installing and using libraries
  • Servo motors
  • Learning to use new components independently/building projects: automated plant watering pump
  • Free flex time: explore components and code with guided support, start discussing and designing month 2 build project

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Class Outline

  • 3D printing overview
  • Types of printers, filaments, safety
  • How to 3D print
  • CAD modeling in Fusion 360

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What is 3D printing?

  • Creating 3D objects by printing thin sheets of material on top of each other
  • Can create aesthetic designs (props, toys) or mechanical, engineering components (gears, brackets, hardware)

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Types of Printers

FDM (Fused deposition modeling)

  • Most common, cheap
  • Fed filament on a roll
  • ABS/PLA filament as well as specialty

SLA (Stereo Lithography)

  • A laser solidifies a photopolymer resin
  • Higher resolution/finish quality
  • Requires UV treatment/safe disposal of resin

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Anatomy of a 3D printer

  • Stepper motors: precise movement and control, drives timing belt or threaded rod
  • Extruder assembly: an internal motor feeds filament, and heater melts solid filament at the nozzle
  • Heated build bed/plate: A heated platform to limit thermal contraction of 3D printed part. Without it, part can warp as the base cools while hot material is added on top

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Types of Filament

ABS

Extruder temp: 220C - 250C

Bed temp: 95C - 110C

Heated bed required, closed chamber recommended

Heat and impact resistant

More durable, better mechanical properties

Petroleum based

Unhealthy fumes - use in ventilated room

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PLA

Extruder temp: 190C - 220C

Bed temp: 45C - 60C

Heated bed optional, closed chamber not required

Not heat resistant

Easier to print

Made of renewable biomass, technically recyclable (but not in practice)

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Other types

PTEG

Nylon

Wood

Carbon fiber infused

Color changing

Conductive

Glow in the dark

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Safety

  • Fumes/airborne particulates: volatile organic compounds (VOCs) can cause long-term health risks
  • Fire: Electrical faults and thermal runaway (caused by failed sensor)
  • Mechanical: Fingers pinched by printer when moving
  • Darwin Awards: Touching the hot end nozzle when at 220C or common electrical risks with power plugs

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3D printing workflow

  • Get a 3D model (in .step, .stl, or .3mf file type)
    • Either find a design online, or design from scratch in a software like Fusion 360
  • Convert file using a slicer software
    • Choose settings for your printer/filament
  • Export sliced file to 3D printer

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Sourcing 3D files online

Thingiverse: https://www.thingiverse.com/

Thangs: https://thangs.com/

Printables: https://www.printables.com/

Cults: https://cults3d.com/

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Slicer Software

Download Cura: https://ultimaker.com/software/ultimaker-cura/

(other slicer softwares available too)

  • Add printer: Creality Ender 3 v2
  • Check material and nozzle size settings
    • (PLA and 0.4mm nozzle used in demo)

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  • How to move/orientate model
  • Model orientation and part strength
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3D Print Prepared File

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Save to SD card

Start print, ensure first layer adheres well

Can pause printer & adjust real time speed through the machine control panel

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Choose print settings

Discussion

  • How to move model
  • Best practices to orientate model for strength

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Configure Settings

  • Resolution/Layer height:
    • Thinner layers print slower but at a high resolution
  • Infill settings (generally 20-40%)
  • Supports
  • Raft
  • Advanced/custom settings

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3D printer settings

  • Changing filament
    • Change Z-height
    • Pre-heat PLA/ABS
    • Once hot, hold down spring and pull filament out
    • Cut new filament at 45 degree angle and insert, holding spring down
    • Keep feeding until filament begins extruding
    • Then cooldown the heater head
  • Bed leveling
    • Prepare/Disable Stepper Motors
    • Manually move the bed and the extruder to the 4 corners and center to ensure the bed is levelled properly.
      • You check by sliding a piece of paper between the nozzle and the bed.
      • You want the paper to gently catch but not rip (too tight) or slide (too loose)
      • When you adjust one corner, always re-check any corners in case the adjustment affects them too.
    • Once levelled, re-home the extruder.
  • Bed adhesion techniques
    • Blue painters tape (not green - doesn’t have great grip), ensure no overlap of tape
    • Or a very thin layer of glue from a glue stick commonly used in kids craft projects
    • Avoid touching bed with your hands - natural oils lead to worse adhesion

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Finishing the Model

  • Should be able to pry off your model but if you can’t and it is on tape, you can also use a spatula to leverage it off.
  • Unload the filament while the printer is hot. Leaving it can potentially jam the extruder for future uses.
  • Clean off the nozzle of any excess filament that was extruded.
  • Make sure to return the USB plug and any small tools to the drawer.
  • To clean off your models just use some snips to trim off the excess material and sand with a high grit sandpaper to smooth out any bumps.

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Troubleshooting & Maintenance Tips

Lots of potential failure points, use this guide to troubleshoot: https://www.matterhackers.com/articles/3d-printer-troubleshooting-guide

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Common fixes:

  • Level build plate
  • Clean nozzle
  • Bed not adhesive enough (add blue painters tape)
  • Incorrect settings for type of filament being used
  • Filament is old/has absorbed moisture

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Designing for 3D printing

Overhangs:

  • Aim to keep overhangs less than 45 degrees, otherwise print with supports
  • The filament doesn’t cool down instantly, and if the next layer doesn’t have enough support, it will droop and fall.

Aim to have a flat base to your model

Printers can bridge overhangs, however they will droop if too long

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MakerLabs Printing

Machine time: $2/hr (with a minimum bill of $5)

Materials: Bring your own, or use MakerLabs shared filament (quality not guaranteed, has been exposed to moisture)

Booking: https://www.makerlabs.com/tool-booking

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Recommended Printers

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Online resources:

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How to design your own models?

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What is CAD?

  • CAD (Computer-Aided Design)

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Common CAD softwares

  • TinkerCAD: online, limited functionality, but easiest to pick up
  • Fusion 360: cloud based, free and paid licenses,
  • Onshape:
  • FreeCAD:
  • Solidworks:

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  • Parametric design vs sculpting (Rhino, Blender)

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Fusion 360

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Workspace Overview

  1. Active files/navigation
  2. File management
  3. User settings/profile
  4. Design Space Toolbar:
    • Solid, surface, mesh, and more
    • Tools of selected environment
  5. Workspace
  6. Navigation cube
    • Rotate cube
    • Pan and zoom with mouse wheel
  7. Right-click quick access tools
  8. User navigation settings
  9. Timeline (will revisit later)

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Other workspaces (not discussed today)

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Design Space Toolbar

Create: Generate 2D profiles/paths and 3D bodies

Modify: Modify the existing profiles/paths/bodies

Assemble: Join components together

Construct: Options to construct planes, axis, and points

Inspect: Renders measurement information in real time or hides measurement info

Insert: Insert a file to use a reference

Select: Default active tool if not using anything else.

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Approach to 3D Design: creating a bolt

  • Create 2D sketches:
    • Using lines, circle, rectangle, arc
    • Dimensions and applying constraints
  • Extrude into 3D
  • Modify in 3D
    • Move, scale, rotate, fillet/chamfer, combine, cut, appearance
  • Parametric timeline

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Exercise: Design a threaded bolt

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Parametric Design

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Using Vernier Calipers

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Design for Manufacturability

Considerations

  • Inclusion of bolt holes or snap joints
  • Tolerances (especially for fit together pieces)
    • When 3D printing use a 0.3mm gap for pieces that fit together
    • Estimation only, tune based on your 3D printer
  • Overhangs and flat mounting surface

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How to export meshes to slicer?

  • Select desired body (right)
  • “Save as mesh”
  • Import saved file into Cura

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Exercise: Design a Electronics Box

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Importing 3rd party designs

  • GrabCAD: https://grabcad.com/library
  • McMaster-Carr: (through fusion interface)

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Advanced Topics (open discussion)

  • SVG for laser cutting and using extensions/add ons
  • Discussion of bodies vs components
  • Designs containing multiple files
  • Other design tools such as lofts
  • Other design spaces such as surface, mesh, sheet metal

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Next Steps

Online resources

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Exercises to practice:

  • Find an object around the house and replicate it
  • Consider how CAD/3D printing can be used in next months project