Dave, If there were any cavity packages, such as mechanical relays, HYBRIDS, CPU's, crystals, etc on the board they could indeed be susceptible to possible mechanical damage caused by the ultrasonics. I have observed the results of individuals placing SEALED hybrids [cavity style packages] into ultrasonic cleaners with devastating results to the wire bonds. Placing the same hybrids into the ultrasonic cleaner in an un-sealed state did not affect the wire bonds [but prove out one's own process to be sure]. Conversely, if the devices are plastic encapsulated PEMs, with no internal cavities, they are essentially immune from any reasonable ultrasonic exposure that I can imagine. If there are cavities - tread with caution. No cavity, total encapsulation - typically safe! My 10 cents Steve Creswick From: [log in to unmask] [mailto:[log in to unmask]] Sent: Wednesday, October 12, 2011 8:14 AM To: TechNet E-Mail Forum; Amol Kane Cc: [log in to unmask] Subject: Re: [TN] Wire soldering question - Utrasonics discussion Hi Amol - you can call it a myth or just old tribal knowledge but for many years there was (and still is in some segments) the idea that ultrasonics - either soldering or cleaning - will damage the die or the wirebonds in components. There are a number of good industry publish investigations that show ultrasonics can be applied for in both the cleaning and soldering applications safely without causing component damage provided you do sufficient process qualification. I am not a fan of ultrasonic soldering as I can ultrasonically solder a toothpick - the solder sticks mechanically and not because I made a metallurgical interface. But, ultrasonic soldering is a viable process provided attention is paid to making metallurgically sound solder joints. Ultrasonics have wide application in cleaning processes. Other TechNetters can provide better information on that aspect than I. Dave Hillman Rockwell Collins [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 -----------------------------------------------------