We can see a piece of soft film (flexible insulating base material) when we open the key disk of general computer, which is printed with silver white (silver paste) conductive figure and key figure. Because of the general screen missing printing method, we call this printed circuit board flexible silver paste printed circuit board. And we go to the computer city to see a variety of computer motherboards, graphics cards, network cards, modems, sound cards and home appliances on the printed circuit board is different. The base material used is made of paper base (commonly used on one side) or glass cloth base (commonly used on both sides and layers), pre impregnated with phenolic or epoxy resin, one or both sides of the surface layer are pasted with copper sheet and then laminated and solidified. This kind of circuit board is covered with copper sheet, which we call rigid board. Then we can make printed circuit board, which we call rigid printed circuit board. We call the printed circuit board with printed circuit graphics on one side and printed circuit graphics on both sides, and the printed circuit board formed by double-sided interconnection through hole metallization, we call it the double-sided board. If a printed circuit board with one double side as the inner layer, two single side as the outer layer or two double sides as the inner layer and two single side as the outer layer is used, the printed circuit board which is alternately connected by the positioning system and the insulating bonding material and the conductive graphics are interconnected according to the design requirements will become a four or six layer printed circuit board, also known as a multi-layer printed circuit board. Now there are more than 100 layers of practical PCB.
Nov 02, 2019
