Jay, Ultrasonic by itself will not normally damage flex circuit constructions. Having said that, what adhesive system and anti-tarnish are you using, and what is the working liquid in your ultrasonic? If the adhesive or anti-tarnish is prone to attack by the solution the ultrasonic can enhance the effect. Andy Magee Flex Guru [log in to unmask] From: "Zhang, Jay" <[log in to unmask]> Would it be Okay to use ultra-sonic to clean polyimide based flex circuit with metal stiffener. Would the ultra-sonic weaken the bond between the circuit and stiffener, destroy the anti-tarnish coating on bare copper, or cause any de-lamination? Thanks in advance for any input. Jay Zhang Sheldahl, Inc. 507-663-8399 ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################