#AU2012 How things get digitally made

Part of our AU 2012 general session mentioned that there are four basic ways that items can get digitally manufactured:

1. Additive manufacturing, like 3D printing
2. Subtractive manufacturing, like CNC milling and laser cutting
3. Robotic assembly
4. Nanobiology, designing and making living things at the smallest scale imaginable

In addition to the general session, I attended Shaan Hurley and Evan Atherton's class on The Future of Making Stuff. Shaan presented a nice summary of six processes used for 3D printing.

1. Extrusion
2. Stereolithography (SLA)
   • Vat of liquid photopolymer resin cured with UV laser
   • Laser cures material in the cross section of current layer
   • Build tray drops down to allow resin to fill next layer
   • Layers typically between .002 inches to .006 inches
3. Selective Laser Sintering (SLS)
   • Tray of powder resin
   • Laser heats up powder until it fuses with the powder around it
   • Build tray drops down and next layer of powder gets drawn over
   • Standard Resolution: .004 inches
4. Fused Deposition Modeling (FDM)
   • Extrusion heads melt rolls of thermoplastics and deposit them in a cross section on a build tray
   • Build tray drops down and next cross section is extruded
   • Standard Resolution: .01 inches
5. Plotjet
6. Inkjet 3D

I used Shaan's PowerPoint slides to construct a summary table.

Method	Material Type	Material Color	Material Cost	Print Resolution	Print Speed
Extrusion	ABS or PLA plastics	one at a time	inexpensive	low	quick
SLA	resin	one at a time	expensive	high	quick
SLS	powder	one at a time	high waste for small parts	good	slower
FDM	thermo- plastics	limited	inexpensive	low	slower
Polyjet	resin	opaque or transparent but limited selection	moderate	super high	slower
Inkjet 3D	ink and powder	full color	moderate	good	quick

3D Printing is alive in the lab.