How many kinds of PCB can be divided according to the material? Where are they used?
Visit：2898 Date：2019-12-26
The mainstream PCB material classification mainly includes the following: using FR-4 (glass fiber cloth-based), CEM-1 / 3 (glass fiber and paper composite substrate), FR-1 (paper-based copper-clad board), metal-based coating Copper plates (mainly aluminum-based, a few are iron-based) are more common types of materials, and are generally referred to as rigid PCBs.
The first three are generally suitable for products with high-performance electronic insulation requirements, such as FPC reinforcement boards, PCB drilling pads, glass fiber mesons, potentiometer carbon film printed glass fiber boards, precision planetary gears (wafer grinding), precision testing Plates, electrical (electrical) equipment, insulating struts, insulation pads, transformer insulation plates, motor insulation parts, grinding gears, electronic switch insulation plates, etc.
The metal-based copper clad board is the basic material of the electronics industry. It is mainly used for processing and manufacturing printed circuit boards (PCBs). It is widely used in televisions, radios, computers, computers, mobile communications and other electronic products.
Extended information:
PCB (Printed Circuit Board), Chinese name is printed circuit board, also known as printed circuit board. It is an important electronic component, a support for electronic components, and a carrier for electrical connection of electronic components. Because it is made using electronic printing, it is called a "printed" circuit board.
After the electronic equipment adopts printed boards, due to the consistency of similar printed boards, errors in manual wiring can be avoided, and automatic insertion or placement of electronic components, automatic soldering, and automatic detection can be achieved to ensure the quality of electronic equipment. , Improve labor productivity, reduce costs, and facilitate maintenance.
The reason why PCB can be used more and more widely, because it has many unique advantages, as follows.
1 High density. For decades, the high density of printed boards has been able to evolve with the increasing integration of integrated circuits and advances in mounting technology.
2 High reliability. Through a series of inspections, tests and aging tests, the PCB can be guaranteed to work reliably for a long period of time (usually 20 years).
3 Designability. For various performance requirements of PCB (electrical, physical, chemical, mechanical, etc.), printed board design can be realized through design standardization, standardization, etc., with short time and high efficiency.
4 Producibility. With modern management, standardization, scale (quantity), automation and other production can be carried out to ensure consistent product quality.
5 Testability. Established relatively complete test methods, test standards, various test equipment and instruments, etc. to detect and identify the qualification and service life of PCB products.
6 Assemblability. PCB products are not only convenient for standardized assembly of various components, but also for automated, large-scale mass production. At the same time, PCB and various component assembly parts can be assembled to form larger parts and systems, up to the whole machine.
7 Maintainability. Since PCB products and various component assembly parts are standardized in design and large-scale production, these parts are also standardized. Therefore, once the system fails, it can be replaced quickly, easily and flexibly, and the system can be quickly restored to service. Of course, you can give more examples. Such as making the system smaller and lighter, and speeding up signal transmission.
Contact processing
The solder-resistant green paint covers most of the copper surface of the circuit, exposing only the terminal contacts for component welding, electrical testing, and circuit board insertion. This terminal needs to be added with a proper protective layer to avoid the occurrence of oxides at the terminals connected to the anode (+) during long-term use, affecting circuit stability and causing safety concerns.
[Plating hard gold] Plate a layer of nickel and a highly chemically inert gold layer on the plug-in terminals of the circuit board (commonly known as gold fingers) to protect the terminals and provide good connection performance. It contains an appropriate amount of cobalt and has excellent Abrasion resistance.
[Tin spray] Cover the soldering ends of the circuit board with a hot air leveling method to cover a layer of tin-lead alloy to protect the terminal points of the circuit board and provide good soldering performance.
[Pre-soldering] Cover the soldering end of the circuit board with a layer of anti-oxidation pre-soldering film by dip dyeing, temporarily protect the soldering end and provide a relatively flat soldering surface before welding, so as to have good soldering performance.
[Carbon ink] Print a layer of carbon ink on the contact end of the circuit board by screen printing to protect the end and provide good connection performance.
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