I don't believe that anybody has mentioned that depending on the component's MSL, factory ambient humidity and how the assembly has been stored it has most likely exceeded its floor limit and may very well need a bake cycle to be removed without damage. John -----Original Message----- From: Dorothy Lush [mailto:[log in to unmask]] Sent: Friday, June 11, 2004 10:13 AM To: [log in to unmask] Subject: Re: [TN] Reusing desoldered components Many more expensive IC's are made to be solderable more than one time. A BGA, for instance, will have in it's spec's how many times it can be reballed which is ususally more times than a PCB location can be reworked. If in your removal of QFP's you use a good temperature controlled rework station to reheat and remove the QFP in such a way that stays within the parts heating specifications then you have alot of leeway for reworking these IC's. In my experience parts with memory tend to be sensitive to overheating. I have had good experince with the Metcal rework stations. They are built to order and they are very good at giving you true temperature at the component and the board surface. Best yet they do not require calibration once in the field because of their design and you can depend on the temperture reading you get. Dorothy Lush Manufacturing Manager 12Telecom International, Inc. -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Randy Bock Sr. Sent: Friday, June 11, 2004 10:11 AM To: [log in to unmask] Subject: Re: [TN] Reusing desoldered components One has to ask is a $2.00 component worth loosing a $1,800.00 board ?? or even a $500.00 one. Randy Bock Sr. Quality Manager Pitney Bowes AddressRight Printers (p) 203 720-3861 (f) 203 729-5397 (email) [log in to unmask] "Whittaker, Dewey (AZ75)" <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 06/11/2004 12:22 PM Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please respond to "Whittaker, Dewey (AZ75)" <[log in to unmask]> To [log in to unmask] cc Subject Re: [TN] Reusing desoldered components Bill, This question is perfect for Doug's patented answer " it depends". Can you or have we made a case where it is acceptable to re-use components? Yes. Should you, if you have to ask, re-use components? No. Knowing your end-use requirements and environment is a must, but just the time and money to read and gather all the things you need to consider before making a decision will probably exceed the cost to scrap initially. Dewey -----Original Message----- From: Kasprzak, Bill (sys) USX [mailto:[log in to unmask]] Sent: Friday, June 11, 2004 8:17 AM To: [log in to unmask] Subject: Re: [TN] Reusing desoldered components Daan, Our policy is to not re-use any soldered parts. I've tried to rationalize situations instances where this would be feasible, such as prior to powered up conditions, but can't win support due to a lack of proof that parts are not over-stressed. Pragmatically, I think there should be some guidelines for re-using parts, limited to prior to powered up conditions. The same pundits who argue that re-use of parts is verboten don't seem to have a problem re-using a board from which parts were replaced. Bill Kasprzak Moog Inc., Systems Group, Process Engineer -----Original Message----- From: Dobbs, Marie [mailto:[log in to unmask]] Sent: Friday, June 11, 2004 10:34 AM To: [log in to unmask] Subject: Re: [TN] Reusing desoldered components Our rule of thumb. If it is removed it is replaced. We have never conducted any studies on potential heat damage, but. Better safe than sorry. -----Original Message----- From: Dehoyos, Ramon [mailto:[log in to unmask]] Sent: Friday, June 11, 2004 10:27 AM To: [log in to unmask] Subject: Re: [TN] Reusing desoldered components Hi Daan: I am not aware of any standards for recycle parts, but wouldn't these parts be in the same situation as reworked parts? Some times there is a need to move parts due to misalignment or for trouble shooting. This requires them to go through the reflow process. Just my one cent. Regards Ramon -----Original Message----- From: Daan Terstegge [mailto:[log in to unmask]] Sent: Friday, June 11, 2004 7:20 AM To: [log in to unmask] Subject: [TN] Reusing desoldered components Hi Technet, We've recently had delamination problems on boards which are populated with some very expensive QFP's. To minimize the damage we want to desolder these parts and use them again. Our customer wants some kind of evidence that the functionality and long term reliability are not affected, and they want this evidence (i.e. thermal profiles) to be related to IPC specifications. I'm not aware of any standard that specifies if reuse of desoldered components is allowed, and which limitations apply to the temperature profiles, but perhaps some of you knows such a standard ? Best regards, Daan Terstegge Thales Communications Unclassified mail Personal Website: http://www.smtinfo.net --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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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 ----------------------------------------------------- --------------------------------------------------- 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 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