Judge the surface technology of PCB and the industries applied by color
With the rapid development of electronIC technology, the process requirements of pcb circuit boards in each industry are different, for example, there are gold and copper in the circuit boards of mobile phones and computers. Therefore, the recycling price of waste circuit boards can reach more than 30 yuan per kilogram. It is much more expensive than selling waste paper, glass bottles and iron. From the outside, there are mainly three colors of the outer layer of the circuit board: gold, silver and light red. Gold is the most expensive, silver is the cheapest, and light red is the cheapest.
From the color, we can see whether the hardware manufacturer has cut corners,
In addition, the circuit inside the circuit board is mainly pure copper. If exposed to air, it is easy to be oxidized, and the outer layer must have the above protective layer. Some people say that gold is copper, which is wrong.
Gold: large area gold plating/gold deposition on the circuit board
The most expensive gold is real gold. Although there is only a thin layer, it also accounts for nearly 10% of the cost of the circuit board. Some places along the coast of Guangdong and Fujian specialized in the purchase of waste circuit boards, stripping off the gold and making considerable profits.
Gold is used for two purposes, one is to facilitate welding, the other is to prevent corrosion.
The following golden finger of the memory module 8 years ago is still shiny. If it were made of copper, aluminum and iron, it would have been rusty and useless.
Gold plating layer is widely used in component pads, gold fingers, connector shrapnel and other positions of circuit boards.
If you find that some circuit boards are all silver, it must be jerry built. The industry term is "costdown".
The main boards of mobile phone circuit boards are mostly gold-plated boards and sunken boards. Computer main boards, audio boards and SMAll digital circuit boards are generally not gold-plated boards.
The golden finger of memory module 8 years ago.
The exposed parts of the circuit board of Phone X are all gold-plated.
Is gold gold and silver silver?
Of course not. It's tin.
The silver plate is calLED tin spraying plate. Spraying a layer of tin on the outer layer of copper wire can also help welding. But it cannot provide long-term contact reliability like gold.
The tin spraying plate has no effect on the components that have been welded, but it is not reliable enough for the pads that have been exposed to the air for a long time, such as grounding pads, spring pin sockets, etc. Long term use is easy to oxidize and rust, resulting in poor contact.
The circuit boards of small digital products, without exception, are tin sprayed boards. There is only one reason: cheap
Small digital products like to use tin plate
OSP, organic soldering film. Because it is organic, not metal, it is cheaper than tin spraying process.
The only function of this organic film is to ensure that the inner copper foil will not be oxidized before welding. The film evaporates when heated during welding. Soldering tin can weld copper wires and components together.
But it is not corrosion resistant. An OSP circuit board cannot be soldered after being exposed to the air for more than ten days.
Many computer motherboards use OSP technology. Because the area of the circuit board is too large, it can not afford gold plating.
Which industries are PCB widely used
PCB design mainly comes from layout design, in which it requires the layout of internal electronIC components, metal wiring, through-hole and external connections, electromagnetic protection, thermal dissipation, crosstalk and other factors. Excellent circuit design can save production costs and achieve good circuit performance and heat dissipation performance. PCB board is the supplier of electrical connection of electronic components. Its development has a history of more than 100 years. Then why is PCB widely used? The following points are listed:
High reliability: We will ensure that PCB can work reliably for a long time through a series of inspections, tests and aging tests.
2. High density: For deCADes, the high density of printed boards has been developing with the improvement of integrated circuit integration and installation technology.
3. Producibility: modern management is adopted, and standardization, scale (quantity), automation and other production can be carried out to ensure product quality consistency.
4. Testability: relatively complete test methods, test standards, various test equipment and instruments have been established to detect and identify the qualification and service life of PCB products for PCB proofing.
5. Designability: For various performance requirements (electrical, physical, chEMIcal, mechanical, etc.) of PCB, PCB design can be realized through design standardization, normalization, etc., with short time and high efficiency.
6. Assemblability: PCB products are not only convenient for standardized assembly of various components, but also for automatic and large-scale batch production. At the same time, PCB and various component assembly parts can also be assembled to form larger parts and systems, up to the whole machine.
7. Maintainability: Because PCB products and various component assembly parts are designed and produced in a standardized way, these parts are also standardized. Therefore, once the system fails, it can be replaced quickly, conveniently and flexibly, and the system can be recovered quickly.
PCB manufacturing, PCB design and PCBA processing manufacturers will explain to you how to judge the surface technology of PCB by color and which industries are applied.