Hi, I am sure its some sticky residues which has not been removed by ur cleaner. We had the same issue and when looked thru magnification and in a particular angle we observed sticky spots. We then had to clean them with IPA. The root cause was due to the time delay in processing between wave soldering and cleaning process. Thanx Badri -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Bloomquist, Ken Sent: Friday, April 06, 2007 7:59 PM To: [log in to unmask] Subject: [TN] Conformal Coat Dewetting Good afternoon all, I've go some assemblies that are not taking conformal coating in some areas. The boards are reflowed and then selective wave soldered with a pallet. They us a water sol flux and run it through an inline wash using DI. We wash them in a batch washer using a mild saponifier prior to coating. The boards are cleanliness tested in a ROSE tester and then coated with polyurethane. It is only on a few boards and it appears to almost be coming from the via's. If we try to brush coat over it it still won't coat. If we clean it with IPA then it coats just fine. We've ruled out silicone and finger grease. I have a couple of photos so you can see what it looks like. One is black light showing the void areas. The other one is where we tried to touch up the coating around a via and you can see how it pulled back. http://www.ema-wa.com/DSCF0845ViaContamAreas.jpg http://www.ema-wa.com/DSCF0840_Via_Close-up_Y1_WL.JPG Thanks, KennyB --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- Disclaimer: =========== This E-mail may contain privileged information and is intended solely for the addressee. Any unauthorized use or dissemination of this message in whole or in part is strictly prohibited. If you have received this mail by mistake, please inform us immediately and delete this mail. Any information expressed in this mail does not necessarily reflect the views of Avalon Technologies (P) Ltd . Avalon Technologies(P) Ltd shall not be responsible nor liable for the proper and complete transmission of the information contained in this communication nor for any delay in its receipt or damage to your system. Avalon Technologies(P) Ltd does not guarantee that the integrity of this communication has been maintained nor that this communication is free of interceptions or interference.We have taken precautions to minimize the risk of transmitting software viruses, but we advise you to carry out your own virus checks on any attachment to this message. We cannot accept liability for any loss or damage caused by software viruses. Thank you for your cooperation AVALON TECHNOLOGIES MAY MONITOR ALL INCOMING AND OUTGOING MAILS. ************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************* --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------