This document provides an overview of 3D printing. It discusses the different types of 3D printing technologies, such as fused deposition modeling (FDM) which is used in most home/hobby 3D printers. It also reviews specific 3D printer models like the Makerbot and Printrbot and the materials they can use, such as PLA and ABS plastics. The document outlines the 3D printing process including designing models, slicing files, generating G-code instructions, and layer-by-layer printing. It highlights some complex prints and larger assembled objects that can be made as well as sharing models through sites like Thingiverse.

1. 3D Printing
Turning molten plastic into neat toys

2. 3D Printing
• Lots of different kinds of 3d printing
• Some use powder, metal, etc.
• Primary home/hobby printing is “FDM” –
Fused Deposition Modelling
– Basically: A glue gun controlled by a printer
– Assembly is layer-by-layer

3. Models: Makerbot
• Consumer-targeted 3d
printer
• Designed to be ‘no
setup’; easy for
consumers
• Costs about $2200

4. Models: Printrbot
• Originally kickstarter
• Typically sold as kits
(but can buy assembled
for $100)
• Varies in cost from
$300-$800
• Targeted at hobbyists.

5. Materials
• PLA
– Biodegradable
– Produced from corn
– Lower melting temperature (compared to ABS)
• ABS
– Higher temperature
– Higher melting temperature
• Can print in other things (teflon; nylon; wood
filament) – much less common (and more
expensive)

6. Costs
• “Filament” (plastic used as input to the
printer) typically costs about $30/kg
– Can be found as low as $20, but “you get what
you pay for”
• Many small items can be made for 50 cents or
so worth of plastic

7. What can you make?
• Just about anything plastic with enough care
• Limited by build volume (Printrbot Plus is 8”
cube) and layering approach
– You aren’t going to build a car with a 3d printer
very quickly
– You’re also not going to build a chandelier very
easily – anything with overhangs can be difficult

8. How it works: Software
• Take a 3D model (STL file)
• Use a ‘slicer’ to turn it into layered paths for
the head of the printer
• Slicer intelligently fills in solid spaces with
material
– Also tries to minimize plastic on the insides of
pieces so as to not waste material

9. How it works: G-Code
• Slicer generates “G-Code”
– a set of “move here, at
this rate” instructions
• G-Code was originally
designed in the 1980s for
driving other computerdriven manufacturing
• G-Code can be
interpreted by firmware
on the electronics
attached to the printer

10. How it works: Repetier
• Software to control
overall interactions with
the printer
• Communicates over
USB to printer
• Has UI to control
position, heat, fan, etc.
• Repetier also has slicing
and G-Code
visualization

11. How it works: Printing
• Melts 3D plastic in a heated head (~200
degrees C)
• Prints onto flat surface – important to get the
first layer right so it sticks
• Motor feeds material through the hot end,
pushing plastic out the other side.
• Motors move the bed and the print head in 3
dimensions to print

12. How it works: Complex Prints
• Some 3D models can’t be printed without
overhangs
• Two basic components: Bridges and support
material
• Bridges are connections between two existing
pieces of plastic
• Support material is thin layers designed to
form a basis for bridges – temporary, intended
to snap-away

13. How it works: Complex Shapes
• Not all complex shapes
are complex prints
though
• Some shapes with lots
of holes in them can still
be printed (relatively)
easily
• Common style: Voronoi
surface

14. How it works: Bigger Shapes
• 3d printing bigger
shapes usually works
via snap-fit or press-fit
pieces
• Push pieces together to
get them to stay

15. Coolest Items
• Articulated excavator:
“Little Digger”,
thing:208315
• Prints as one piece
• Wheels, cab, and arm
move

16. Coolest Items
•
•
•
•
Fidget cubes
Prints as one piece
Hinged
thing:230139

17. Finding Models: Thingiverse
• Thingiverse is a 3d model repository that
offers lots of 3d models
• Social – can also share 3d models, share
‘makes’, etc.
• Supported by Makerware
• Good to find first things to print – toys,
puzzles, printer improvements…

18. Designing Models: OpenSCAD
• OpenSCAD is 3D
Modeling for
programmers
• You write 3D models
with code
• Can import and export
common formats

19. Designing Models: Sketchup
• Sketchup – formerly from Google – is another
design tool
• Free plugin to support export to STL
• Can be used as a visual design tool (rather
than code)

20. Creating your own Filament
• Filament extruders can be purchased as kits
for a few hundred $
• Take in plastic pellets ($7-$10/kg instead of
$30-$40)
• No commonly available way to re-melt prints
currently, but people are working on recyclers

21. Other types of 3D Printing
•
•
•
•
Powder bed 3d printing
Laser sintering
Laminated
Light Polymerized

22. Things to know
• 3D Printers – at least, printrbot – is *not* a
commercially ready tool
– It requires a lot of tinkering and tweaking to get good
prints
– When the answer from support to a problem is “Pull
out your multimeter and measure the resistance” you
know you’re in a hobbyist market
• If you buy a kit – expect it to take a while to build
• Bed level is important: Bed level and belt tension
are the two most important aspects of good
prints

23. FAQ
• Have you printed a gun?
– No. This is a silly use of 3d printing, there are lots
of easy ways to build your own gun.
• How long have you had it?
– About two weeks
• Is it made of wood?
– Yep