Standard For Evaluating PCBs By Cap Oil And By Plug Oil
Three formal definitions through processing and general inspection standards
One: open the window through the hole,
Definition: The window opens through the tin on the through hole
Inspection standard: tin furnace and hand solder can be very good tin
Two through the cover oil
Definition: As long as there is no tin on the via, the via will be covered by oil (because it will be tinned if there is no oil), which is the most mature process used in the industry.
The occurrence and causes of yellowing of through holes:
Green oil is on the through hole, because green oil is a thick liquid, the height of the through hole is higher than the surface of the plate, and the middle of the through hole is hollow, the liquid will flow down slowly, and in the oven after 300 The high temperature and high temperature will make the green oil flow faster, so the through hole will turn yellow, and the green oil on the through hole will be affected by the screen strength and angle, the screen version, and the thickening of the green oil. Hole yellow is an inevitable phenomenon in the process of over-hole covering oil!
Third: through hole plug oil
Definition: This name indicates that the hole is full of oil. This process is a supplement to the double-hole cap oil because the capping oil does not resolve the yellowing of the pores and the plug oil completely resolves the pores. The problem of yellowing on the palate, this application is in bga, it is a particularly demanding board, but the cost is very high, and Garry Chong does not provide the hole plug oil process for the time being!
Inspection standard: the mouth can not appear yellow, can not tin, must have green oil, and is opaque