Raye, Do you receive legacy units, that have been subjected to this burn-in, back for repair from your customers, or are they disposable or repaired elsewhere? If you get them back, do you monitor these customer returns to determine any failure percentage, and time to failure calculations? In other words, you need to evaluate how well your present burn-in is working, before making changes. It may be sufficient for your design and your customer use environment. Have your products design fundamentally changed, or are using very similar parts and construction? What are the typical failure modes of your components, and how would you precipitate those failure modes? What is the rated temperature range of your products? Personally, I would say a stagnant burn-in at 50 C won't precipitate many failures. Temperature cycling while powering on/off is generally used for ESS, as well as vibration if your products are used on the move. MIL-HDBK-344 may be good reading for you to see the military products viewpoints. Jim Carlson Quality/Configuration Manager L-3 Communications Applied Signal & Image Technology 443-457-1111 Ext. 238 -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Rivera, Raye Sent: Wednesday, June 08, 2011 5:00 PM To: [log in to unmask] Subject: [TN] How to determine Burn In duration? Hello Technetters, Does anyone know of a good reference on how to reasonably set the duration for burn in of products? I haven't been able to locate much information on this topic. Our products are primarily fiber optic telecom equipment. We burn them in at 50 degrees C for 48 hours. This procedure was set up before my time and I do not know how it was arrived at. Lacking any better approach, I would probably put 10 or so units into a long term burn in experiment and measure time to failure. Then, attempt to fit to a Weibull distribution and see if I can get a theoretical model for what percentage will fail after X hours of burn in. I'm not sure if this is reasonable because the sample is small and the time to failure may be quite long. Does anyone know of a better approach? Thanks all! Best regards, Raye Rivera QA Manager * Canoga Perkins 20600 Prairie Street * Chatsworth * CA 91311-6008 818-678-3872 * [log in to unmask] ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 16.0 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 For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 16.0 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 For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------