The overall situation of China's copper processing industry is mainly as follows: the economic operation index is stable, the profit is slightly increased, and the overall profit rate of the industry is still low. However, compared with 2016, the debt ratio has decreased; the output has increased year by year, and the output of each sub-category has increased; Long-term net import, import substitution is slow. The strips, foils, rods and wires are all net imports, and copper and copper clad are net exports.

PCB, commonly known as printed circuit board, is an indispensable part of electronic components and plays a central role. In a series of PCB production processes, there are a lot of matching points. If you are not careful, the board will be flawed, and the quality of the PCB will end up in an endless stream. Therefore, after the circuit board is formed, the test is an indispensable part. Let's share with you the failure of the PCB circuit board and its solutions.

1, PCB circuit board often occurs in the stratification reasons:

(1) Supplier material or process issues

(2) poor design and poor copper distribution

(3) The storage time is too long, exceeds the storage period, and the PCB circuit board is damp.

(4) improper packaging or preservation, damp

Response: Choose the package and store it with constant temperature and humidity equipment. Do a good job in the factory reliability test of PCB circuit board, for example: thermal stress test test in PCB circuit board reliability test, responsible supplier is to take more than 5 times of non-layering as standard, in the sample stage and mass production every cycle It will be confirmed, and the average manufacturer may only request 2 times, and it will be confirmed once every few months. The IR test of the analog placement can also prevent the outflow of defective products more, which is a must for an excellent PCB factory. In addition, the PCB plate Tg should be selected above 145 ° C, so that it is safer.

Reliability test equipment: constant temperature and humidity chamber, stress screening type thermal shock test chamber, special equipment for PCB reliability test.

2, PCB board solderability is poor

Cause: The placement time is too long, resulting in moisture absorption, the layout is contaminated, oxidized, black nickel is abnormal, solder-proof SCUM (shadow), and anti-solder PAD.

Solution: Pay attention to the quality control plan of the PCB factory and the standards for maintenance. For example, black nickel, need to see whether there is no gold out of the PCB board production plant, whether the concentration of the chemical line is stable, whether the analysis frequency is sufficient, whether the regular stripping test and the phosphorus content test are set to detect, whether the internal soldering test is Have good execution and so on.

3, PCB board bending board

Reason: The supplier's material selection is unreasonable, the heavy industry is poorly controlled, the storage is improper, the operation pipeline is abnormal, the copper area of each layer is obviously different, and the fracture hole is not made firmly.

Responsive measures: press the board with the wood pulp board and then pack and ship it to avoid deformation in the future. If necessary, add a clamp on the patch to prevent the device from over-bending the board. The PCB needs to be simulated before the packaging to simulate the placement of IR conditions, so as to avoid the phenomenon of plate bending after the furnace.

4, PCB board impedance is poor

Cause: The impedance difference between PCB batches is relatively large.

Response measures: Manufacturers are required to attach batch test reports and impedance bars when delivering, and if necessary, provide comparison data between the board diameter and the board edge diameter.

5, anti-weld foaming / shedding

Reason: There is a difference in the selection of solder resist inks, and the PCB board anti-welding process is abnormal, resulting in heavy work or patch temperature.

Response: PCB suppliers should develop PCB board reliability testing requirements and control them in different production processes.

6, the Cavalier effect

Reason: The electrons dissolve into copper ions in the process of OSP and ginseng, resulting in a difference in potential between gold and copper.

Response: Manufacturers need to pay close attention to the potential difference between gold and copper in the production process.

Longxiang circuit board is positioned in the professional manufacture of LED aluminum substrate, high-density exposure circuit board, high thermal conductivity aluminum substrate, FR4 composite board and other circuit boards. The company has a professional team engaged in the production of circuit boards for nearly 20 years, with many excellent engineers and professional management personnel, as well as a full set of automated production equipment and precision testing equipment for professional production of circuit boards (aluminum substrates, glass fiber boards). . The company's entire production process is self-sufficient, with a monthly output of 20,000-30,000 square feet per month. Products are widely used in LED commercial lighting, security camera light board, car light lighting, aircraft flashing lighting and new energy batteries.