3D printers can be used with any curricular area. They are especially useful for practicing the design process and getting students used to iteration of design.
Tinkercad is the iPad app that D181 currently uses to design for the 3D printers.
3D Printing: An Introduction
by Stephanie Torta, Jonathan Torta
The Invent To Learn Guide to 3D Printing in the Classroom: Recipes for Success
by David Thornburg
The Art of Digital Fabrication: STEAM Projects for the Makerspace and Art Studio
by Erin E. Riley
High-tech DIY Projects With 3D Printing
by Maggie Murphy