I have two suggestions. One has already been suggested and that is to keep the coated cards away from elevated temperatures as long as possible. The second suggestion is to thin the conformal coat which allows the entrapped air to escape easier. Jon ---------- From: Lum Wee Mei [SMTP:[log in to unmask]] Sent: Monday, August 31, 1998 9:27 PM To: [log in to unmask] Subject: [TN] Bubbles from conformally coated board The test engineer came back to us to complain that bubbles are found along the edge of the power modules after going through the temperature cycling tests. This problems are found on both coated boards. The power modules are mounted completely flushed onto the board and subject to conformal coating using the diping method. The coated board undergo QC to ensure all components are completely coated, inlcuding the edges around the modules. What could be the problem? ################################################################ 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 ################################################################ ################################################################ 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 ################################################################