3d printing allows for customization, complexity, rapid prototyping, and lower costs compared to traditional manufacturing. There are various 3d printing techniques that build objects layer by layer from materials like plastic or metal powder. While 3d printing has limits like strength and size, it enables personal fabrication and sharing of designs. Issues around its use include intellectual property, economics, and regulation of printed objects like guns. Proper modeling and preparation are needed to ensure successful 3d printing.

1. 3d printing: History and current
techniques
And some playing around with Origami

2. What is 3d printing?
• Using a general-purpose machine to create a physical object, where
the design of the structure is provided to the machine at build-time.
• Usually, the object is created additively, in a layer-by-layer process.
• Compare to "CNC" (computerized numerical control) which usually
refers to a subtractive process like carving, routing, turning or
cutting.

3. Why do we care about 3d printing?
• Personalization and customization
• you can make a single copy of a thing, which is prohibitive with
traditional manufacturing
• Complexity
• you can make objects with complicated internal structures, which
is difficult with traditional manufacturing

4. Why do we care about 3d printing?
• Rapid prototyping
• Can make a physical instance of a design, and quickly tell if it's
the right size and shape for a job
• Can iteratively refine a design based on real-world performance
• Modelling for traditional manufacturing
• Build a complex shape, and use it as a mold for a more traditional
material process like metalwork

5. Why do we care about 3d printing?
• NRE (Non-recurring engineering) costs
• eg: $100,000 to set up a production line, each
copy after than costs $0 (and a few seconds of
time)
• (idealized, for a small simple part)
• 3d-printing a copy costs $5 (and a half hour of
time)
• Once you are making more than 20,000 copies,
traditional manufacturing is cheaper.
• Traditional manufacturing is also far higher
quality and far faster.
$400k NRE versus 3d printing
$0.00
$2.50
$5.00
$7.50
$10.00
Units (thousands)
10 20 30 40 50 60 70 80 90 100
cost/unit (traditional)
cost/unit (3d print)

6. How did we make things before 3d printing?
• Carve the part out of wood or plaster
• Also, carve the internal structure of the part separately
• Cast a series of molds of stronger materials until you have a steel
form for the inside, and a separate steel form for the outside
• Pour molten plastic (metal, whatever), and let cool
• eject the part from the mold
• Alternatives: cornstarch molds for food gels like gummies

7. What are the limits of 3d printing
• a 3d printed part is not as good as a manufactured part.
• more fragile, lower resolution, more expensive and takes longer to produce
• 3d printing requires specialized equipment and materials
• a 3d printed part requires a 3d design file
• expert knowledge required to produce a design
• but, designs can be shared and modified
• Consumer 3d printing is limited to thermoplastics, and ~10cm3
build area

8. 3d printing and social change
• NRE means it’s only feasible to make a thing if you can sell tens of
thousands of them, or if you can charge a lot for them
• commodity versus luxury; walmart versus bespoke
• 3d printing means things can exist that are both inexpensive and
non-commodity
• 3d printing has limits, so how does this extend to other things?

9. Fab Lab
• 10 machines to build anything
• 3d printing is one of them
• laser cutters arguably have higher utility and usability
• Circuit miller is arguably more important for making high tech things
• Price is prohibitive, but dropping

10. 3d printing controversies
• Guns or other restricted things
• 3d printer means anyone can make anything
whether or not the government likes it
• as long as it’s made of plastic and the size
of a loaf of bread
• 3d printed guns are not very good guns, and
people make bombs out of pots and pipes

11. 3d printing controversies
• Printing Bioproducts
• Printing custom pills with exact dosages
• Printing organs for transplant
• Printing biotoxins and chemical weapons

12. 3d printing controversies
• Information Ownership
• Many corporations are identifiable by their
physical products
• Coke bottles, toys associated with movies,
nike shoes
• Design patents prevent consumer confusion
by disallowing one company from
manufacturing a product with similar or the
same “trade dressing”

13. 3d printing controversies
• Economics, industry
• What happens to the world economy when
people can print whatever they need at
home?

14. Different kinds of 3d printing
• Selective Laser Sintering (SLS)
• Fused Deposition Modelling (FDM)
or Fused Filament Fabrication (FFF)
• Stereolithography (SLA)
• Powerbed gluejet printing
(3d printing proper)
➡ laser-melted nylon power
➡ melted thermoplastic
filament
➡ Photo-cured acrylic resin
➡ metal power and glue, later
annealed with copper
most consumer printers

15. Know your material
• FDM/FFF printing can use a few different thermoplastic materials
• Acrylonitrile butadiene styrene (ABS) : Strong, food-safe, lego plastic;
awesome.
• Polylactic acid (PLA): biodegradable; derived from corn, tapioca or other
plants. more brittle, higher melting temperature, harder to work with, not
as strong. more properly called a polyester.
• Specialized thermoplastic materials: ninjaflex, conductive plastic,
chocolate etc.
• All have specific properties that will influence your ring

16. Know your printer
• Each printer is different, and fail in different ways
• Know your printer and maker custom supports and modifications
• eg mouse ears
• Fit tolerances for connecting parts and external parts

17. SLS
$1,000,000

18. Consumer SLA
$100, or $3500

19. Consumer FDM
$500-$5000

20. Model Replication
• To replicate a physical model on a 3d printer, there are two ways
• 3d scanning
• Model Measurement
• (third way: find someone online who’s already made one)

21. • Many commercial products and
maker plans
• Microsoft kinect, makerbot
digitizer, etc
3d scanning

22. 3d scanning
• 3d scanner is expensive
• (but getting cheaper)
• Many layers of
postprocessing required
• (but getting easier)

23. Model Measurement
• Use the right tools
• Calliper, protractor etc
• be precise
• Model as you Measure
• Aim for easy replication
• think construction process
• Find inspiration from existing models

26. 3d modelling software
• Tinkercad
• Blender
• Sketchup
• Zbrush
• Meshmixer, Meshlab, Netfabb

27. 3d modelling in sketchup
1. Set template to “3d printing: millimetres”
2. Install STL export extension
1. click on the ruby box (install extensions)
2. double-click “Sketchup STL”
3. click “download”

28. Scale
• Consider the smallest discernible element your printer can generate
• Simplify your model to match characteristics of the printer
• Don’t try to print (or even model) anything smaller than 2 mm
• Use the right tool for the job: metal pins and screws are better at
providing mechanical structure than 3d printed plastic

29. Edges, planes and points
• Building an object that looks nice in sketchup is easy
• Building an object that prints well is hard
• Edges can’t just look close, they must meet exactly.
• Objects must be water-tight and right-side out
• the printer will try to do what you tell it to do. If you say print an
inside-out box, it will try. and fail.

30. Boxes
right side out inside out

31. Making a box
• Draw a rectangle
• type in numbers to provide an exact size, in mm
• Extrude the rectangle into a box with push/pull
• NOTE: points, edges, and planes are all separate and can be
manipulated

32. Sketchup Tools
• Line; Arc; Rectangle; Push/pull; Offset; Move; Rotate; Scale;
• Also: follow me; constrain to axis
• Xray mode can be useful for finding problems with internal structure
• sketchup will try to help you
• midpoint, parallel to edge, on edge

33. Rotate
• rotate a plane or edge
• everything selected is rotated
• Everything else is fit as best as
possible
OK
Bad

34. Move
• rotate a plane, edge, or point
• everything selected is moved
• Everything else is fit as best as
possible
OK
Bad

35. DEMO: origami box
in 10 minutes of modelling

36. Wall Width
• A box will be printed solid (filled in
with infill specifications)
• A frame can be built so it will not be
filled in. Choose wall widths for
appropriate strength

37. Support
• FDM printers layer melted plastic
on each previous layer
• Some things are impossible
• Aim for, at most, 45 degree
overhang, 2.5 cm bridge
• otherwise, add your own
removable support, or tell the
software to calculate support

38. Print Orientation
• Consider the way in which your
model will be printed
• You may choose to separate your
model into more than one piece, to
make support-less printing possible
not as good good

39. Model Segmentation

40. 3d modelling for origami
• Flat surfaces, simple
folds
• look at “low-poly” (low-
polygon count) models
for inspiration

41. Aside: foldable 3d prints and CNC
• Special modelling techniques:
flexible and bendable joints, hinges
etc
• flexible materials: ninjaflex
• Thermoformable / hydroformable
materials (also called 4d printing:
3d plus time)