Hi Juan,

Recommended shelf life is dependent on the finish. It is also dependent on the particular plating PRODUCT for a given finish.

The recommendations minimum shelf lives are listed in the Plating specification IPC standards. They are:



6 months to a year for HASL

IPC 4552 for ENIG (it should be good for at least 6 months)

IPC 4553 for Immersion Silver (it should be good for at least 6 months depending on which product is used)

IPC 4554 for Immersion Tin (typically only about two weeks due to intermetallic formation. Copper and tin love each other and begin diffusing almost immediately, and this leads to poor solderability).

OSP shelf life is only about 3 months, but again it depends on which product it is. For example Entek Basic is good for 3 to 6 months but Entek Plus is good for 6 to 12 months.



And of course, it all depends on the applicator, the thicknesses, the proper packaging and storing practices, etc. For example IAg cannot be stored near sulphur emanating from such things as motor oils, laundry soaps, engineers who eat a lot of hard-boiled eggs and then drink a lot of Mountain Dew, etc.

There is some good information in IPC 1601 on this also.

Odin



-----Original Message-----

From: TechNet [mailto:[log in to unmask]] On Behalf Of Juan T. Marugan

Sent: Wednesday, March 06, 2019 2:37 PM

To: [log in to unmask]

Subject: [TN] PCB shelf life



Hi all.



My question is regarding the PCB shelf life. Should a PCB be considered as an age sensitive product (that is, with an  expiration date)? If yes, is shelf life defined in any standard?



What do you suggest to do when shelf life has passed: scrap?



Thank you so much for your feedback.



Juan



Indra (Spain)