pcb four layer circuit board preservation time has how long
four-layer circuit board preservation time how long four-layer board concept
Four-layer board (4 layers) refers to the circuit printed circuit board PCB Printed Circuit Board made of 4 layers of glass fiber, which can reduce the cost of PCB but the performance is poor. Then four-layer board, double-sided, single-sided, 6-layer board --- and so on how to distinguish, the following is to distinguish the number of layers of PCB.
Four-layer circuit board storage time.
pcb four-layer circuit board preservation time and surface treatment process is inextricably linked, gold and electroplating is the longest preservation time, at room temperature conditions, can be saved for two to three years, followed by spray tin and anti-oxidation, by its anti-oxidation, get the board is best immediately on line, it is the shortest preservation time, about 3 months or so, the long inventory of the board must be baked before the line, otherwise over Reflow soldering when it is easy to explode the board.
If the antioxidant process four-layer board, not unpacked vacuum packaging, used up within six months, unpacked vacuum packaging within twenty-four hours, and is temperature and humidity controlled environment, the board in the unpacked under a year to use up, unpacked in a week should be pasted piece, the same to control temperature and humidity, gold plate equivalent to tin plate, but the control process is stricter than the tin plate.