How Long Is PCB Storage Time?
There is a storage time after PCB complete manufacture.it need be baked if more than storage time,otherwise there easy occur burst board problems when make SMT.The storage time of PCB and the temperature and time of baking PCB are standard in industry.
I. Regulation of PCB control
(1.) PCB unpacking and storage
- (a.) PCBs can be directly use online if unopened within 2 months manufacturing date.
- (b.) PCBs must be labeled unpacking date within 2 months manufacturing date.
- (c.) PCBs must be finished use online within 5 days after unpacking within 2 months manufacturing date.
(2.) PCB Baking
- (a.)PCBs in the manufacturing date within 2 months of sealing opened more than 5 days, please take 120 +/- 5 ℃ baking for 1 hour.
- (b.)If PCBs exceeds 2 months of manufacture date, please bake for 1 hours at 120 + /5 ℃ before online.
- (c.)PCBs are over 2 months to 6 months before the manufacture date, please bake for 2 hours at 120 +/- 5 ℃ before the online.
- (d.)PCBs are over 6 months to 1 year after the date of manufacture, please bake for 4 hours at 120 + /-5 ℃ before on-line.
- (e.)PCBs be baked should be used within 5 days (put into IR REFLOW), it need to bake one more hour before reuse.
- (f.)If PCBs are more than 1 year before the date of manufacture, please refer to the 120 +/- 5 ℃ baking 4 hours, sending back to PCB factory to remake HASL.
(3.)The method of PCB baking
- (a.)Large PCBs place with flat,a stack up to 30pcs,open the oven and take out PCBs flat to natural cooling( need press fixture to anti warp and twist) after baking completed.
- (b.)Medium and small PCBs place with flat,a stack up to 40pcs,upright type is not limited,open the oven and take out PCBs flat to natural cooling( need press fixture to anti warp and twist) after baking completed.
II. Preservation and baking of PCB in different regions.
The specific storage time and baking temperature of PCB are not only related to the manufacture ability and manufacturing process of PCB manufacturers, but also to the region.
OSP and pure gold PCB, the storage time is usually 6 months, for the OSP process is generally not recommended to bake. The region is a great related to PCBs preservation,in general moisture is heavy in southern region,it’s very damp in Spring.PCBs must be used up within 24 hours,otherwise easy to oxidation,it’s the best used up within 8 hours after unpacking.The weather is generally dry in the Northern region,PCB has a longer storage time and a shorter baking time.the baking temperature is generally 120+/5℃,baking time according to the specific circumstances to decide.
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