What determines the quality of a PCB circuit board?

Although many customers and friends have been deeply involved in the electronics industry for many years, as the saying goes: the technology industry has specialties! For the judgment of the authenticity of the PCB circuit board, maybe you are really not sure. The editor has been in the PCB industry for ten years. Today, I will simply tell my friends: the three factors that really determine the quality of the PCB board!

One: hole copper.

Hole copper is a very critical quality indicator! Because the conduction of each layer of the board depends on the hole copper, and this hole copper needs to be electroplated with copper. This process is time-consuming and expensive to produce. Therefore, in an environment of low price competition, some factories began to cut corners. , shorten the copper plating time. Especially some allegro factories, in recent years, many allegro factories in the industry have begun to apply the "conductive adhesive process". The advantages of this process are: fast speed, low cost, and an average cost saving of 20-30 yuan per square meter. However, it has a fatal flaw, that is, the thickness of the copper plating is not enough.

This can be said to be a secret within the industry, and few people outside the PCB industry know it. The board made with conductive adhesive technology has thin and uneven hole copper. If used in consumer products, it can meet the needs, but if your product requires quality, it must be energized for a long time, under vibration, under conditions. Beware!

What determines the quality of the PCB circuit board?

Two: Plates.

In the fixed cost of PCB, the circuit board accounts for nearly 30%-40% of the cost. It is conceivable that many board factories will cut corners on the use of boards in order to save costs. Everyone knows that the sheet we use, scientific name: FR-4, is a glass epoxy resin. The difference between a good board and a bad board is as follows:

1. Fire rating. In our industry, there is a secret that is kept secret. Many board factories are using non-flame retardant boards. This ratio is huge! If you tell me that the price of the 2-layer board you bought is less than 300 yuan/square, then I will tell you, please take out a lighter and see! Non-flame retardant sheets can be ignited. If non-flame retardant sheets are used in your product, the consequences are risky. Evaluate this yourself!

2. Fiber layer. Qualified panels are usually pressed from at least 5 pieces of fiberglass cloth. This determines the breakdown voltage and fire tracking index of the board.

3. The purity of the resin. Poor quality sheets have a lot of dust. It can be seen that the resin is not pure enough. This kind of board is very dangerous in the application of multi-layer boards, because the holes of the multi-layer board are small and dense!

Three: Repression.

Whether the kanban factory has the strength, whether it specializes in multi-layer boards, you only need to ask one question: do you have your own laminating machine?

At present, many small factories in the market are outsourced. Why? First, the pressing equipment is expensive and the cost is high. Secondly, if you are not a professional multi-layer board manufacturer, you will generally choose external pressure.

     For multi-layer boards, pressing is a very important process! Whether it is pressing equipment, technology, management, personnel experience, all determine the quality of pressing! Poor compression will seriously affect 3 points:

1. The board layer is not well combined, and it is easy to delaminate.

2. Impedance value. PP is in a state of glue flow under high temperature pressing, and the thickness of the final product will affect the error of the impedance value.

3. The finished product rate. For some high-level PCBs, if the distance from the hole to the inner layer line and copper is only 8 mils or less, then the pressing level must be carefully tested. If the stack is offset, the inner layer is offset, and the holes are drilled during pressing, there will be a lot of open circuits in the inner layer.

For PCB boards, appearance, V-cutting, surface treatment, etc. are not the most critical issues. These are all manageable and salvageable quality hidden dangers, but the above three points are the most critical for a PCB board.