Fellow Techs, Some new designs have moisture sensitive devices (MSDs) such as BGAs on both sides of the pwb. A lot of effort is put into making sure that the MSDs are properly packaged, not opened until ready for use so they stay within the allotted floor life, etc.. Some MSDs are level 5 sensitivity which only have a 24 hour floor life. What I would like to hear about is how assemblers handle MSDs when they are already mounted on 1 side of the board, maybe aqueous washed and then see another reflow cycle when the other side of the board is assembled/reflowed. Are the MSDs/boards rebaked which adds a lot of cycle time but maybe necessary? Assembled within the allotted floor life for the most sensitive MSD - probably the most ideal situation? Not washed until both sides are reflowed which doesn't make sense when using water soluble flux? Or, stored in a dry-box until ready for the 2nd side reflow - which should work. Also, what impact does aqueous cleaning have on a mounted MSD? Does it saturate the MSD with moisture requiring a bake out? I look forward to hearing how other users manage this problem. thanks joe --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------