Hi Annie - there is very good article on blowholes that you will find helpful - get a copy of : "The Harmfulness of Blowholes in PTH Soldered Assemblies" , Colin Lea , Circuit World, Vol. 16, No. 4, 1990, pages 23-28. The article covers blowholes in great depth (pardon the pun :) ) and lists several additional references. Good Luck. Dave Hillman Rockwell Collins [log in to unmask] annie laberge <[log in to unmask]> on 01/06/99 08:29:29 AM Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please respond to annie laberge <[log in to unmask]> To: [log in to unmask] cc: Subject: [TN] pinholes Good morning everyone On some of our products, we have pinholes in Through holes solder joints. We have no idea what is the root cause of these pinholes. Could the root cause come from the PCB ? And if so, what default in the PCB could cause this ? These products are 8 layers PCB, with 4 ground planes which 2 of them are on outer layers, and 0.093" thick, and the hole diameter is 0.023". With these products, we had lots of problems. Fist we had missing solder because of the lack of heat caused by the heat disssipation of the ground planes. We optimised our wave parameters to minimize the problem. Then we had blow holes. The root cause was humidity in the board. We don't have this problem anymore. Any help would be greatly appreciated, thanks in advance. A. Laberge Quality Eng. Matrox ################################################################ 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 ################################################################