Jul 02, 2023

Fibercuit Laser

It is now easier than ever before for makers to get nice PCBs (Printed Circuit Boards). With free, open source software like KiCAD, they can send off designs to a number of affordable PCB fabrication houses and get professional-quality boards back in as little as a week. But even a week can be too much time if you’re going through several PCB design iterations, which is why DIY PCB fabrication techniques still have a place in our community. Developed by a team from the University of Maryland's Small Artifacts Lab, Fibercuit is an interesting new fiber laser-based PCB fabrication system that can quickly create prototype PCBs and even form 3D copper objects.

There are two common at-home PCB fabrication techniques in use today: chemical etching and milling. Etching is a tried-and-true method that utilizes special chemicals to dissolve unmasked copper on a PCB blank, leaving behind traces and pads. But etching is messy, requires manual drilling of through-holes, and results in boards that are obviously homemade. Milling is more straightforward, but it does require a milling/engraving machine and those aren’t cheap. It also necessitates the use of a respirator and careful cleanup to prevent inhalation of harmful substrate dust in the air.

Fibercuit is a better technique if you happen to have access to a fiber laser cutter/engraver. Fiber laser cutters are not cheap — they’re far more expensive than low-power solid state lasers and even powerful CO2 lasers. It probably isn’t worth buying such a fiber laser just for fabricating PCBs, but Fibercuit is appealing if you already have a fiber laser.

This technique isn’t revolutionary (laser-cut PCBs are already a thing), but the sophisticated software control and streamlined process make it stand out. The idea is simple: the fiber laser cuts the borders of the copper traces, pads, and so on. To create a blank for this process, the user applies Kapton tape (the substrate) onto thin copper sheet. A roller helps to remove the bubbles. The software takes a PCB design file and sets the laser to a lower power density level to cut through only the copper, leaving the Kapton substrate intact. A higher power density level can cut through the Kapton to “drill” through-holes.

Fibercuit has two additional tricks up its sleeve. First, it can use the laser to melt solder paste and form solder joints. That eliminates the need for manual soldering and speeds up the overall process of making a prototype. Those solder joints aren’t exactly clean, but they do work. It can also bend portions of the board with the very precise application of heat. That is useful for producing 3D “kirigami” PCBs, which we’re sure that some creative folks can find a way to apply to their projects.