Lum Wee, You ask what could be the problem: If Conformal Coating is subjected to elevated temperature (subjective as to what is elevated temperature), before fully curing, the solvents remaining in the coating can try to rapidly outgas and create bubbles. Extended room temperature time for curing may solve the problem, your process may or may not have time for full cure before entering temperatures generated by other curing ovens, testing of high wattage components, temperature cycle or temperature testing. Have experienced this problem in my production lines. Semper Fi Tom > ---------- > From: Lum Wee Mei[SMTP:[log in to unmask]] > Sent: Monday, August 31, 1998 8:26 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 ################################################################