1) Don't dip it if theres any problem, you get a thicker buildup on one side relative to the other. 2) Use a soft coating that stretches (some silicones and urethanes are in the shore A scale) and absorbes almost all of the CTE mismatch. 3) The supplier can provide a recommended reflow and cooling profile. Make sure you're oven is set within the profile. ARIC PARR Sr. Manufacturing Engineer Eaton Corp 1400 S. Livernois P. O. Box 5020 Rochester Hills, Mi 48308-5020 [log in to unmask] 248 608 7780 Fax: 248 656 2242 ------------- Original Text From: C=US/A=INTERNET/DDA=ID/TechNet(a)IPC.ORG, on 7/22/98 11:13 AM: To: Aric Parr@01635@Lectron_RH, EatonWHQ@CorpMail@WHQCleveOH[C=US/A=INTERNET/DDA=ID/TechNet(a)IPC.ORG] REGARDING ASSY:Reliability, SMT With regards to surfmnt glass diodes (melf-type), how does one protect the body from conformal coating. In the past, we sleeved the axial body to protect it from CTE mismatch. I haven't yet contacted Mfg about the exact P/N of the conformal coat material. Is this necessarily the reason for crack initiation? Could the cause be the 'cooling' slope during reflow, thereby allowing the coating mismatch to propogate the cracking? ################################################################ 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 ################################################################