What determines the quality of PCB?
Although many client friends have been deeply engaged in the electronIC profession for many years, as the saying goes: there is expertise in the field! As for the determination of the real quality of PCB, perhaps you really have a choice. Xiao Bian has been working in the PCB profession for ten years. Today, I would like to tell my friends briefly: the three elements that really determine the quality of PCB boards!
1： Hole copper.
Hole copper is a very crucial quality index! Because the continuity of the circuit of each layer of the board all depends on the hole copper, which needs to be plated by sinking copper, this process takes a long time, and the production cost is high, so under the environment of low price competition, some factories begin to cut corners and shorten the copper plating time. Especially in some Allegro plants, many Allegro plants have started to use a "conductive adhesive process" over the years. The advantages of this process are: fast speed, low cost, and cost savings of 20-30 yuan per square meter. However, it has a fatal defect, that is, poor copper plating thickness.
This can be said to be a secret of the professional world. Few people outside the PCB profession know this. The plates made by the conductive adhesive process are thin and uneven. If they are used in consumer products, they can meet the demand, but if your products have requirements for quality, they must be careful when they are powered on and vibrated for a long time!
In the fixed cost of PCB, boards account for nearly 30% - 40% of the cost. It is conceivable that many board factories will cut corners in the use of boards in order to save cost. We all know that the sheet material we use, scientific name: FR-4, is a glass epoxy resin. There are several differences between good plates and poor plates:
1. Fire rating. Here is a secret that our profession does not disclose. Many board factories are using non flame retardant boards. This proportion is very large! If you tell me that the price of the 2-layer board you bought is below 300 yuan/m2, I will tell you, please take out the lighter and light it! Non flame retardant sheet can ignite. If the non flame retardant sheet is used in your product, the consequence risk will be evaluated by yourself!
2. Fiber layer. The qualified plate is normally formed by pressing at least 5 pieces of glass fiber cloth. This determines the breakdown resistance voltage and fire MARKing index of the board.
3. Purity of resin. There are a lot of poor plate material dust. It can be seen that the resin is not pure. This kind of plate is very dangerous in the use of multilayer plates, because the holes of multilayer plates are very SMAll and dense!
To see whether a board factory has the strength and whether it is professional or not, you only need to ask one question: Do you have your own pressing machine?
Now many small factories in the market are outsourcing, why? First of all, pressing equipment is expensive and expensive. Secondly, if it is not a professional manufacturer of multi ply boards, they generally choose external pressing.
For multilayer boards, pressing is a very important process! The quality of pressing depends on the pressing equipment, process, management and personnel experience! The poor crimping will seriously affect 3 points:
1. The board layer has poor adhesion and is easy to delaminate.
2. Impedance value. PP is in flowing state under high temperature pressing, and the final product thickness will affect the error of impedance value.
3. Yield of products. For some PCB boards with high multilayer, if the distance between the hole and the inner layer wire and the copper sheet is only 8mil, or even less, the pressing level should be strictly tested. If the lamination is offset and the inner layer is offset when pressing, and the hole is drilLED, there will be many open circuits in the inner layer.
The above is the explanation given by the editor of pcb circuit board company. If you want to know more about PCBA, you can go to our company's home page to learn about it. In addition, our company also sells various circuit boards,
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