3D Printing: What’s Realistic for TVIs?

Joan Horvath & Rich Cameron

2/26/2018 1

Topics • What is a 3D printer? • Technology issues

– Common types of Printers – Materials

• Workflow and issues • Making a good teaching model • Where to learn more

3D printing

– The piece gets bigger

as you work on it – Build up one layer at

a time – Overhanging pieces

may require support

2/26/2018 3

Filament-based printers

2/26/2018 4

Printing with Filament(FFF)

2/26/2018 5

SLA/DLP (resin)

2/26/2018 7

SLA - Resin Printers (Formlabs Form 2) https://formlabs.com/3d-printers/form-2/

2/26/2018 8

Images courtesy of Formlabs

Filament vs SLA/DLP

2/26/2018 9

Filament SLA/DLP

Cost of machine $300-$3000 $1000-$4000

Cost of unit of material $30-$50/kg $50-$150/liter

Material handling Easy ( spool of plastic filament)

Moderate (resin, cleanup chemicals)

Smallest feature size About 1 mm About 0.1 mm

Use any STL file Yes, with support Yes, with (different) support

Post process options Sanding, clipping off support, painting

Same

Bottom line Easiest to use, cheaper Better resolution (e.g. labels on tactile graphs, delicate, complex objects)

Making 3d Printable Models

• Consider – Layer lines (not smooth surface) – Feature size needed – Need for support (might be fixed with orientation,

cutting part into pieces) – Braille labels? (Can always paste on instead – this

seems to be a best practice)

2/26/2018 10

3D Printing Workflow

• Make a 3D CAD file, or – Download a file from a database – Scan existing object (not very mature yet)

• “Slice” the file into layers – Some printers have proprietary software that does

stuff for you, but limit options

• Print

2/26/2018 11

3D CAD programs

• OpenSCAD (has non-visual interface option) • Tinkercad • Onshape • Blender • Sketchup, Maya, many others

2/26/2018 12

OpenSCAD (OpenSCAD.org)

2/26/2018 13

Code-based modeler- openscad.org

OpenSCAD command-line workflow

• On a Mac or Linux machine – Open terminal window – Launch the program from the command line

• On Windows – Online documentation for command prompt

• See manual at www.openscad.org for options and capabilities

• Screen reader works for menus but not editing (entirely)

2/26/2018 14

Examples: Teaching Models (All created in OpenSCAD)

2/26/2018 15

All Models Same Volume

https://hackaday.io/project/11312-3d-prints-for-teachers-of-the-visually-impaired

Hollow, with lids

NACA airfoil model allows selecting airfoil type, taper, sweep. Put model on a postal scale in front of a fan and measure how the weight appears to fall due to lift.

From Horvath & Cameron (2016), 3D Printed Science Projects. New York: Apress

Airfoil OpenSCAD

Orbits of comets & planets Height is orbital speed - Kepler’s

Laws in plastic

From Horvath & Cameron (2016), 3D Printed Science Projects. New York: Apress

Hacker Calculus http://hackaday.io/project/20621-hacker-calculus

Calculus intuitively!

Laser cutting vs. 3D printing Laser Cutting 3D Printing Requires 2D model (.DXF) Requires 3D model (.STL) Fast (can make a bunch of parts)

Slow

Produces 2D part (can etch) Produces 3D part Expensive machine ($12-20K) Much less expensive machine

($1-2K), less prep Wood, acrylic, paper, cardboard, NOT some plastics, and etch metal

PLA, ABS, nylon, others

Significant facility preparation (venting, fire risk)

Minimal facility prep

2/26/2018 21

Where to Learn More: our Books

Where to Learn Even More

• Our website: www.nonscriptum.com • Check out our Lynda.com or LERN Network

online classes, under the “classes” tab • Join our Google group, linked under the

“projects” tab • Contact us

Joan Horvath joan@nonscriptum.com Rich Cameron rich@nonscriptum.com