The immersion gold plate and the gold plate are two processes of the PCBA manufacturer as ALLPCB. For the gold plating process, the effect of tin on it is greatly reduced, and the effect of the gold is better; unless the manufacturer insists on the requirements, most manufacturers will choose the gold process!
Under normal circumstances, PCB surface treatment is as follows: gold plating (electroplating gold, immersion gold), silver plating, OSP, spray tin (lead and lead-free), these are mainly for FR-4 or CEM-3 For sheet metal, the paper base material also has a surface treatment method of rosin coating; if the tin-on-iron defect is excluded, the solder paste and other patch manufacturers are excluded from the production and material processing reasons. There are several reasons for this:
1. When printing on the PCB, whether there is oil film on the PAN position, it can block the effect of tinning; this can be verified by the soldering test.
2. Whether the PAN bit is in compliance with the design requirements, that is, whether the pad design is sufficient to ensure the support of the part.
3. Whether the pad is contaminated, this can be obtained by ion contamination test; the above three points are basically the key aspects considered by PCB manufacturers.
The advantages and disadvantages of several methods of surface treatment are that each has its own strengths and weaknesses! In terms of gold plating, it can make the PCB storage for a long time, and it is less affected by the external environment temperature and humidity (relative to other surface treatments), generally can be stored for about one year; tinned surface treatment is second, OSP again, this Both surface treatments should pay attention to a lot of storage time in ambient temperature and humidity. Under normal circumstances, the surface treatment of sinking silver is a bit different, the price is high, the storage conditions are more demanding, and it needs to be processed with sulfur-free paper packaging! The storage time is about three months.