Where theworld gathers for metal finishing
Q&As since 1989
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Shelf life of PCB / PWB
Q. I am trying to find statistics about the shelf life of various printed circuit board finishes. We are interested in data on how the different finishes affect the shelf life. I have been unsuccessful in searching the web. Especially interested with HASL, Immersion Tin, Immersion Gold, Hard Gold and OSP.
James Hampshire- Ivyland Pennsylvania, USA
2000
A. I'm somewhat surprised you couldn't find anything. The EPA's got a program going on to evaluate alternative surface finishes for PWB's through the Design for the Environment project. This program is compiling exactly the information you're looking for, and copies of their report are free for the asking. Search their website; I'd tell you exactly where to go if the rules let me.
James Totter, CEF
- Tallahassee, Florida
2000
Ed. note: Thanks James. Sure you're welcome to paste a copy of that report here, James. We'd be more than pleased to make it available to our readers.
Thanks, Ted. The URL to order is: www.epa.gov/ncepihom/catalog.html
The report is "Implementing Cleaner Printed Wiring Board Technologies: Surface Finishes"
The document number is EPA744R00002
James Totter, CEF
- Tallahassee, Florida
2000
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Ed. note Jan. 2020: That report is now at https://www.epa.gov/sites/production/files/2013-12/documents/pwb_surface_finishes_guide.pdf
Multiple threads were merged: please forgive repetition, chronology errors, or disrespect towards other postings [they weren't on the same page] :-)
Q. I work for SONY handling PCBs. A few customers buy in bulk and use the PCB gradually. The problem is the life span of PCB is no where clearly stated. Some of the PWB had corrosion traces after few year in storage.
Would you please let us know the shelf life before and after assembly of a PCB. Is there any difference between supplier Is there any difference between PCB class 1, 2 and three What is the recommended storage environment for PCB Under severe condition such as boat shipment, is there any life span reduction After auto mount insertion process, RHU machine etc, the PWB is exposed to ambient condition, what is the expected life span
Haris M. HarowiSony Technology Malaysia Sdn Bhd - BB. Bangi, Selangor, Malaysia
2003
A. Your questions are very difficult to give you a clear answer.
PCB (PWB) are many difference surface finishing, some of them will be coat some flux to protect copper, please give more detail of type of your stock; Base material type: Phenolic, CEM, FR-x, G-x, etc. Type: Single Side, Double Side, MLB, Flex. Process: Std PTH, Silver plug hole, etc. Surface finishing: Bare copper, HASCL, Hard Gold, Emersion Gold, Carbon paste, etc. Protective coating: Flux, etc.
After assembly, mostly are put on Tin-Lead solder, problem will be cleaning process, packing and stock environment.
Suvatn Srisanan, Mr.- Bangkok, Thailand
2003
Q. We have several PCBs for a PLC that are stored in our store for 10 years. My question is : What is the estimated storage life of a PCB (industrial controls)? If it was designed for harsh environment, does this mean longer storage life?
Thanks,
Ahmad Alsaleem- Riyadh, Saudi Arabia
2004
Multiple threads were merged: please forgive repetition, chronology errors, or disrespect towards other postings [they weren't on the same page] :-)
Q. What is the shelf life of PCB's of type mentioned below:
Base Material : NEMA FR4
Finish Type : SMOBC
Single, Double PCB's
Punjab Communications Limited - Chandigarh, Chandigarh, India
2003
A. The exposed copper on SMOBC boards are subject to oxidisation / corrosion. So, shelf life is very less. Depends on your storage conditions. You need top remove the oxidised layer before you start soldering. You can ask for a solderable lacquer coating after SMOBC. Else, you could go for SMOBC +HALS. This way the shelf life would increase up to six months.
Hope this helps.
V.RAMANAND KINI- India
2003
Q. Sir/Madam,
I am working as a Quality Control Engg. in a Contract Manufacturing Industry in Chandigarh. I want to ask a question & is given below:--
Q :-- What is the shelf life of a PCB in virgin condition {i.e., Without HAL}. Please tell me the same in both type of PCBs {Single & double sided }.
Mukesh Kumar Dhimanconsumer electronics mfgr. - Chandigarh, India
2003
A. Sir your question you are asking cannot simply be answered. Copper oxidizes depending on what environment it is stored in. Are your boards being stored in a controlled environment? If not then your shelf life will decrease dramatically. Your question is like asking how long will an apple stay fresh? If I leave it outside where the elements and bugs can attack it or if I keep it in the refrigerator the answer will be different.
Protecting the exposed copper from the elements is the crucial part of your question.
The only answer I can give you is protecting the copper from exposure will significantly increase your shelf life. A SMOBC board stored air tight in low humidity will last much longer than one stored out in the open of a warehouse.
But you would like a definite answer. I am sure I could clean up a board that's been sitting on the shelf for 3-5 years and make it functional with proper cleaning/etching off the exposed copper in a reasonable environment. Does that mean I would like that board installed on the airplane I was about to take a flight in? No not really.
Hope this helps.
- Portland, Oregon
August 18, 2010
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