This article presents the operation of a CNC router controlled by a free open source firmware (GRBL) that runs on the Arduino Uno R3 card, thus describing and justifying the components that are part of the electrical-electronic system and the computer programs that constitute the software system for the machining of printed circuit boards. The tests performed recorded an estimated time of 21: 86 in minutes: seconds divided into the three processes of engraving (paths 13:12, holes 6:48 and contour 2:26 given in minutes: seconds), these values can vary depending on the dimensions of the required PCB, even so it turns out to be more efficient in quality and time compared to the conventional method of chemical attack.