PCB is one of the indispensable parts of electronic equipment, it appears in almost every kind of electronic equipment, in addition to fixing a variety of large and small parts, the main function of PCB is to let the parts electrical connection. Since the raw material of PCB board is copper-covered board, copper dumping will occur in the process of PCB production. Then what are the reasons for copper dumping of PCB board? Here is to introduce it to you.
Four reasons for PCB board copper throwing
1, PCB circuit design is not reasonable, with thick copper foil design of too thin line, will also cause excessive line etching and copper.
2, copper foil etching is excessive, the electrolytic copper foil used on the market is generally single-side galvanized (commonly known as gray foil) and single-side plated copper (commonly known as red foil), the common copper is generally more than 70um galvanized copper foil, red foil and 18um below the basic ash foil has not been a batch of copper.
3. Local collision occurs in PCB process, and the copper wire is separated from the substrate by external mechanical force. This defect manifests as poor positioning or orientation, falling copper wire will have obvious distortion, or in the same direction of the scratch/impact mark. Peel off the bad part of the copper wire to see the copper foil surface, you can see the normal color of the copper foil surface, there will be no bad side erosion, copper foil peeling strength is normal.
4. Under normal circumstances, as long as the hot pressing high temperature section is over 30min, the copper foil and the semi-cured sheet are basically combined, so the pressing generally will not affect the binding force of the copper foil and the substrate in the laminate. However, in the process of laminate stacking and stacking, if PP pollution or copper foil surface damage, it will also lead to insufficient bonding force between copper foil and substrate after laminate, resulting in positioning (only for the large plate) or sporadic copper wire loss, but the stripping strength of copper foil near the stripping line will not be abnormal.
In order to study EDA technology and SCM technology in depth, the following keyboard, EDA technology and SCM technology application analysis, in order to effectively improve the technical level of software development, promote the long-term development of software development industry. In the study of EDA technology and single chip technology in the application of the keyboard, the use of EDA related software and programming download software, as well as the corresponding single chip microcomputer and supporting compilation software. Keyboard is generally selected matrix keyboard, has a wide range of practicability.
The application of EDA and single chip microcomputer in keyboard
In keyboard Settings, keys are set through the focus of the line and column lines, the two ends of the key switch and the line and column lines respectively connected. The connection of the line is through the pull-up resistance, so the line is in high level without any operation. When the key operation is carried out, the line will affect the level of the line, thus causing the change of the level of the line. The level of the line varies with the level of the column line. If the column line is high, the line is high. This is used in key recognition.
According to the keyboard key arrangement basis, in the use of EDA technology and single-chip technology, the matrix keyboard column line and line is used by the multi-key sharing, reduce the chip I/O interface possession, greatly improve the use of the keyboard speed. In the keyboard, the use of EDA technology and single-chip microcomputer technology to connect the signal, when the line and line affect each other, you can effectively control the key, to achieve the key closure. At the same time, through the combined application of EDA technology and SCM technology, can effectively control the switch of the keyboard, the keyboard operation at any time, so as to complete the corresponding work according to the relevant instructions.
EDA technology and SCM technology in the application of the keyboard, can help the keyboard to complete a variety of complex operations, in order to achieve effective control of the screen display, so as to switch different pictures, complete different tasks. The promotion and application of EDA technology and SCM technology in each industry, to the continuous improvement of economic efficiency of each industry provided ****, promoting the long-term development of Chinese software industry, is of great significance for promoting the modernization construction of our country.