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Reasons for copper coating:
EMC, for large-area ground wires or power copper wires, will play a shielding role, and some special ones, such as PGND, play a protective role.
2. The PCB process requirements of flexible PCBmanufacturers are generally in order to ensure the electroplating effect, or the laminate is not deformed, the PCB layer is covered with copper, and the wiring is less.
3. The signal integrity is required to provide a complete return path for high-frequency digital signals and reduce the wiring of the DC network. Of course, there is heat dissipation, special equipment installation requires copper and so on.
2. Advantages of copper:
The advantage of copper coating is to reduce the impedance of the ground wire (the so-called anti-interference is also because the impedance of the ground wire is reduced by a large part). There are a lot of spike currents in digital circuits. Therefore, it is more necessary to reduce the ground impedance. It is generally believed that a circuit composed entirely of digital equipment should be grounded over a large area, while for analog circuits, the ground loop formed by copper coating may cause electromagnetic coupling interference (except for high-frequency circuits). So it’s not that the circuit must be covered with copper (by the way: mesh copper is better than the whole piece in performance)
3. The significance of copper coating:
The copper wire is connected to the ground wire to reduce the loop area.
2. Large-area copper coating is equivalent to reducing the resistance of the ground wire and reducing the voltage drop. From these two points of view, whether it is digital ground or analog ground, copper should be applied to increase the anti-interference ability. At high frequencies, the digital ground and analog ground are separately laid with copper, and then connected at a single point.
A single point can be wound several times on the magnetic ring and then connected. However, if the frequency is not too high, or the working conditions of the instrument are not bad, it can be relatively loose. The crystal oscillator can be counted as a high-frequency source in the circuit. Copper can be laid around the crystal housing and grounded, which is better.
FPC circuit board is also called flexible circuit board, or “flexible board”. In the industry, FPC, is a printed circuit board made of flexible insulating substrate (mainly polyimide or polyester film), which has many advantages that hard printed circuit boards do not have. For example, it can bend, roll, fold, use FPC can greatly reduce the volume of electronic products, meet the needs of electronic products in the direction of high density, miniaturization, high reliability, therefore, FPC in space, military, mobile communications, Laptop computers, computer peripherals, PDA, digital cameras and other fields or products have been widely used.
FPC lamination process: lamination and opening die feeding / closed die prepressing / cooling / opening / cutting process ready TPX detached film\ steel\ silica gel and dust adhesive cloth or dusting paper to clean steel before the production of the following process: 1. Board\ silica\ off film surface dust, Sundries, etc. The size of the detached film (500m*500m) is opened and placed in the laminated area. After one cycle of each lamination, 400 pieces of spare steel plates are needed, so that the continuous production will not break the material. When laminating operation, you should wear gloves with both hands or fingers with 5 fingers.
It is strictly forbidden to touch soft plates with bare hands. D. When the plate is stacked, the steel plate is placed first. Keep this stack of 10 layers (except for special requirements), with the number of FPC placed on each layer to determine the number of pendulable FPC layers per 1PNL plate size (the distance from the plate to the four sides of the silica gel should be maintained above 7cm), The FPC should be placed in the middle of the silica gel as far as possible, and each plate should be spaced at a distance of 2 cm.
The thickness of the FPC should be consistent in each layer (for example, the single panel cannot be mixed with the multilayer PCB), and every opening and every layer of FPC should be the same. And the position and order of the pictures are roughly the same. When placing, the FPC coating surface or the paste reinforcement surface should be faced up, and the detached film should be flat and covered on the soft plate without wrinkling or folding. After the operation, the stacked FPC should be laid flat on the transport belt. To the next procedure.
