  Prototyping compact devices with unique form factors often requires the PCB
manufacturing process to be outsourced, which can be expensive and
time-consuming. In this paper, we present Fibercuit, a set of rapid prototyping
techniques to fabricate high-resolution, flexible circuits on-demand using a
fiber laser engraver. We showcase techniques that can laser cut copper-based
composites to form fine-pitch conductive traces, laser fold copper substrates
that can form kirigami structures, and laser solder surface-mount electrical
components using off-the-shelf soldering pastes. Combined with our software
pipeline, an end user can design and fabricate flexible circuits which are
dual-layer and three-dimensional, thereby exhibiting a wide range of form
factors. We demonstrate Fibercuit by showcasing a set of examples, including a
custom dice, flex cables, custom end-stop switches, electromagnetic coils, LED
earrings and a circuit in the form of kirigami crane.
