There are a number of different methods that can be used to construct printed circuit boards (PCBs), some of which are additive in nature, and others that are subtractive. Two common subtractive methods, both of which start off with a board that is entirely coated in copper, are etching and milling. The milling process involves using a computer numerical control (CNC) router to carve away the unnecessary areas of copper, resulting in conductive pathways and other similar structures. PCB CNC router devices are most commonly used for rapid prototyping, and can create both through-hole and surface mount technology (SMT) circuit boards.
Circuit boards are components that are designed to perform two basic functions. One of these is to provide physical support for a variety of electronic components. The other purpose is to provide electrical connectivity for those components, which is necessary in order to create working circuits. There are a number of different types of circuit boards, and a few different ways to construct PCBs. The most common methods are subtractive in nature, which means that they start off with boards that are coated in copper or another conductive material.
