Talk about the manufacturing technology of PCBA board

PCBA plate making is very important, gold plating, tin plating process is also very important, below we talk about various processes.

Advantages and disadvantages of various coatings: First, we have to understand why nickel plating, silver plating, tin plating, tin plating, zinc plating, gold plating. We usually use tin plating and gold plating. Common: The coatings all have a common benefit of being antiseptic (improving antioxidant capacity) and playing a decorative role.

Here are the differences

1. Galvanized: The main purpose is to prevent corrosion, it is characterized by low cost, easy processing, good effect, the disadvantage is not suitable for friction parts, will affect the welding performance, the general use of less people.

2.2. Nickel plating; The plating after working in the atmosphere and lye chemical stability is good, not easy to change color, more than 600 degrees Celsius to be oxidized, high hardness, easy to polish, the disadvantage is porous.

3. Tinning: high chemical stability, almost insoluble in dilute solution of sulfuric acid, nitric acid and hydrochloric acid, good weldability.

4. Chrome plating: decorative chrome plating and hard chrome plating. Decorative chromium mainly plays a beautiful and anti-corrosion role, the disadvantage is not wear-resistant. Hard chromium is mainly used to improve the hardness, corrosion resistance and hardness of the workpiece.

5. Gold and silver plating: It mainly plays a decorative role and an anti-corrosion role. The disadvantage is that it is expensive. Why the gold plate

A. As the integration of IC becomes higher and higher, the IC feet are more and more dense. The vertical tin-spraying process is difficult to blow the thin pad flat, which brings difficulties to SMT mounting;

B, in addition, the shelffife of the tinspray plate is very short, and the gold-plated plate is a good solution to these problems: for the surface mount process, especially for 0603 and 0402 ultra-small table stickers, because the flatness of the pad is directly related to the quality of the solder paste printing process, and the quality of the subsequent reflow welding plays a decisive role. Therefore, the whole plate gold plating is often seen in high-density and ultra-small surface paste processes.

C, in the trial production stage, affected by factors such as component procurement, is often not the board to weld immediately, but often have to wait for a few weeks or even a few months to use, gold-plated plate shelflife is many times longer than lead-tin alloy, gold-plated PCB in the sample stage cost and lead-tin alloy plate compared to little difference.

3. Why do you use sink gold:

Gold plating process is divided into two kinds (here the gold is generally not pure gold but nickel gold), one is electric gold plating and one is gold plating (chemical way), for the gold plating process, the effect of tin is greatly reduced, and the effect of gold plating on tin is better; Unless the manufacturer requires a Bonding, otherwise most manufacturers will now choose the sinking process!

1, because the crystal structure formed by gold and gold plating is not the same, gold will be gold more yellow than gold plating, customers are more satisfied.

2, because the crystal structure formed by gold plating and gold plating is not the same, gold plating is easier to weld, will not cause poor welding, cause customer complaints.

3, because the gold plate only has nickel gold on the pad, the signal transmission in the skin effect is in the copper layer will not affect the signal.

4, because the crystal structure is denser than that of gold plating, it is not easy to produce oxidation.

5, because the gold plate only has nickel gold on the pad, it will not be produced into gold wire caused by short.

6, because the gold plate only has nickel gold on the pad, the welding resistance on the line is more firmly combined with the copper layer.

7, the project will not affect the spacing when making compensation.

8, because the crystal structure formed by gold plating and gold plating is not the same, the stress of the gold plating plate is easier to control, and it is more conducive to the processing of the Bonding products. At the same time, because the sinking gold is softer than the gilding, the sinking gold plate is not wear-resistant to the goldfinger.

9, the flatness and durability of the gold plate are on par with those of a standard gold plate.