Hi Hui Luo Your reply confused me a little so I would like to try to clarify my understanding. At first it seemed that you were looking for storage after the PCBA was completed the assembly process. Now it seems to me that you are asking about conditions of a dwell time between two assembly operations. Maybe you can help clarify. I can tell you the following: 1. For bare PCBs IPC did a study that showed that when held at office conditions, PCB had no problem with solderability after two years of storage. 2. Regarding moisture: All PCBs absorb moisture to some extent based on the laminate material. After baking the board can absorb to equilibrium relatively quickly 8-16 hours. So if the board is in a humid environment it could absorb faster. 3. If you are stopping between two operations, I would be concerned about any in process residues on the assembly and the potential for residue impact on subsequent processes. Best regards, Dave David W. Bergman 大山人 Vice President, International Relations IPC - Association Connecting Electronics Industries 3000 Lakeside Drive Suite 309 S Bannockburn, IL 60015-1249 USA +1 847-597-2840 tel +1 847-615-5640 fax +1 847-867-1388 mobile [log in to unmask] www.ipc.org -----Original Message----- From: [log in to unmask] [mailto:[log in to unmask]] Sent: Monday, October 26, 2009 8:49 PM To: David Bergman Cc: Jack Crawford; Jeanne Cooney; Listserv TGAsia; Tom Newton Subject: RE: [TGAsia] shelve life and storage informations req Hi David, Thanks for you prompt feedback! I agree your words that assembly should set up serious procedure for ESD and we always do that. Why I raise that question is because there will be many issues brought if the idle time between SMT and assembly is certain long, such as solderability issue, delamination issue, solder balling issue... Per our experience, there will be big risk if the idle time more than 5 days after SMT. Now in Emerson Network Power Group, we would like to set down this requirement, but first we wish get comment from you. Best Regards HuiLuo Manufacturing Engineering, MECH Embedded Computing & Power Emerson Network Power Tel:0760-88865196 Email:[log in to unmask] David Bergman <DavidBergman@ipc .org> To Hui Luo/AP/Artesyn@ASTEC 10/27/2009 09:27 cc AM Jack Crawford <[log in to unmask]>, Tom Newton <[log in to unmask]>, Jeanne Cooney <[log in to unmask]>, Listserv TGAsia <[log in to unmask]> Subject RE: [TGAsia] shelve life and storage informations req Dear Hui Luo, I have never seen a document that established this type of requirement. I assume the temperature and humidity requirement would be similar to the PCB. I assume also there would be more concern about ESD control. Best regards, Dave David W. Bergman 大山人 Vice President, International Relations IPC - Association Connecting Electronics Industries 3000 Lakeside Drive Suite 309 S Bannockburn, IL 60015-1249 USA +1 847-597-2840 tel +1 847-615-5640 fax +1 847-867-1388 mobile [log in to unmask] www.ipc.org -----Original Message----- From: [log in to unmask] [mailto:[log in to unmask]] Sent: Monday, October 26, 2009 8:03 PM To: David Bergman Cc: Jack Crawford; Tom Newton; Jeanne Cooney; Listserv TGAsia Subject: Fw: [TGAsia] shelve life and storage informations req Dear David and other IPC officers, Besides below, can you help to advise is there any documentation to describe the shelf life/storage condition/handling requirment for the PCBA after SMT or wave soldering? Best Regards HuiLuo Manufacturing Engineering, MECH Embedded Computing & Power Emerson Network Power Tel:0760-88865196 Email:[log in to unmask] ----- Forwarded by Hui Luo/AP/Artesyn on 10/27/2009 08:57 AM ----- David Bergman <DavidBergman@IPC .ORG> To [log in to unmask] 10/22/2009 12:08 cc PM Subject Re: [TGAsia] shelve life and Please respond to storage informations req Asia Committe Task Group Forum <[log in to unmask]>; Please respond to David Bergman <DavidBergman@IPC .ORG> Hi Patricia, IPC committees are working on IPC-1601 Printed Circuit Board Storage and Handling Guidelines. You can get to the draft document at the link noted below: http://www.ipc.org/committeedetail.aspx?Committee=D-35 Best regards, Dave David W. Bergman 大山人 Vice President, International Relations IPC - Association Connecting Electronics Industries 3000 Lakeside Drive Suite 309 S Bannockburn, IL 60015-1249 USA +1 847-597-2840 tel +1 847-615-5640 fax +1 847-867-1388 mobile [log in to unmask] www.ipc.org From: TGAsia [mailto:[log in to unmask]] On Behalf Of Patricia Lui Sent: Wednesday, October 21, 2009 10:06 AM To: Listserv TGAsia Subject: [TGAsia] shelve life and storage informations req Dear Friends, Can anyone advise me are there any documentations which indicates the PCB raw material, bareboard or PCBA storage conditions and shelve life. Have anyone of you experience PCBA after storage of one year have appear via holes failure issues? Anyone have ever encounter or studies in this area? Hope to have your favourable advise. Thanks & Best Regards Patricia Lui Xuan Technologies. Yahoo! Toolbar is now powered with Search Assist. Download it now!