The most work I have seen done in this area has been by B. Richards and P. Burton of GEC Marconi (UK). One of their best papers is out of the IPC Technical Review, June 1990, pp. 15-27, "Does Ultrasonic Cleaning of PCBs Cause Component Problems: An Appraisal." The EMPF also references this paper in their TS0040, "Ultrasonic Cleaning of Military PWAs," April 1991. In a nutshell, they say the gidelines are: 1) use "sweep" frequencies of 40 kHz or higher, 2) Use power of 11 watts/liter of wash solution or less and 3) ultrasonically wash for 10 minutes or less. If you need copies of these articles, send me an e-mail with your fax number and I will send them off when I return from Productronica. Regards, Bill Schreiber Smart Sonic Corporation P.S. In the 11 years that we have offered our ultrasonic cleaning process, I have never had a user contact me with PCB damage problems. --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------