Origami Inductors: Rapid Folding of 3-D Coils on a Laser Cutter

Origami manufacturing, the use of folding to create 3-D shapes using 2-D fabrication tools and techniques, is a promising avenue for creating low cost parts. In this letter, we demonstrate the hands-free cutting and folding of 3-D inductor geometries from blank metal foil using only a 2-D laser cutter. Laser forming, localized laser heating to create thermal stresses to deform a workpiece, is used to fold traces out of plane without manual handling. The laser forming of thin copper foil is first characterized, followed by cutting and folding of two 3-D inductors: a three-turn planar coil with folded overpass and a twelve-turn toroid. The planar coil was found to have inductance 199 nH and peak quality factor of 99.7 at 54.7 MHz, while the toroid had inductance 159 nH with peak quality factor 64.9 at 86.7 MHz. With laser cutters, one of the most widely available machine tools, this technology allows custom, high performance electrical passives to be rapidly fabricated without specialized equipment.