What are the Classification of FPC circuit board?
The classification of the FPC circuit board is based on its medium and structure and is as follows:
1. Single-layer flexible board
This type of flexible board is the simplest type of flexible board. It is usually a substrate + transparent plastic + copper foil combined, of course, protective film + transparent plastic can be added. First of all, the copper foil is subjected to etching and other processes to obtain the necessary circuit, and the protective film is drilled to expose the corresponding pad. After cleaning, the two are combined by rolling. Then, the exposed pad portion is plated with gold or tin for protection. In this way, the big board is ready. It is also generally necessary to punch into a small circuit board of a corresponding shape. There is also a method of directly printing a solder resist on a copper foil without using a protective film, so that the cost will be lower, but the mechanical strength of the circuit board will be deteriorated. Unless the intensity requirement is not high and the price needs to be as low as possible, it is best to apply a protective film method.
2. Double-layer or multilayer flexible board
When the circuit is too complex, single-layer board cannot be wiring or need copper foil for ground shielding, you need to use double-layer or even multilayer board. The most typical difference between a multilayer board and a single board is the addition of a via hole to connect copper foils. The first processing method of the general substrate + transparent plastic + copper foil is to make vias. First drill holes in the substrate and the copper foil, plate certain thickness copper after cleaning and the vias are ready. The following production process is almost the same with that of single-layer board.
3. double-sided flexible board
Both sides of the double-sided board have pads, which are mainly used for connection with other circuit boards. Although it is similar to a single-layer board, the manufacturing process is very different. Its raw material is copper foil + protective film + transparent plastic. First, drill the holes on the protective film according to the position of the pad, and affix the copper foil, etch the pad and the lead, then affix the other protective film with hole drilled.