1. Customers often design that there is no window on both sides of the VIA hole with green oil, or there is a headache on the circuit board. Or open the window on one side. What should I do with this design?

2. The first thing to consider is what kind of surface treatment is used for this circuit board. If it is HA LS, I must prevent the use of single-sided plug hole process. Because the depth of single-sided plug hole is low, it is easy to cause solder beads during tin spraying, which has a great impact on the appearance.

3. If the circuit board is treated with other surfaces, such as gold, OSP, silver, etc., it can accept single-sided plug holes. After considering the above factors, we will look at the customer's green window design. If the window is partially opened, we should try to prevent the use of green oil to cover the hole edge and allow green oil to enter the hole, because this way is also easy to cause solder beads.

4. To sum up the above two situations, a good solution is to allow 1-2MIL tin coils around the double sided plug hole or green oil cover hole, which is popular with circuit boards. Of course, the oil plugging here is for ordinary photographic oil, not thermosetting oil.