Good Afternoon all, I have received Class 3 PWB's built of Polyimide material. We reviewed the cross section sent in with the order. In the supplier provided cross sections we found the resin material fracturing all around the plated holes. Into these cracks, copper has plated. It appears that the feed rates were a bit excessive during the drill operation, and some "punching" perhaps occured. The copper plating in the cracks indicate that solution at one time founds it's way into these cracks. The copper plated cracks extend 2 to 5 mils from the hole into the laminate. Sometimes these plated cracks extend beyond the pads, into the "B" evaluation zone for Laminate Voids. This raises concerns with possible shorting, and/or spacing violations. I see two evaluation options. Evaluate the plated cracks as wicking, or evaluate the plated cracks as laminate voids. Or other ideas? How would you evaluate the copper plating in these fractures? When is it "too much"? Again, these are Class 3, Hi-rel PWB's. Thanks for your thoughts. George Franck Raytheon Systems Falls Church Virginia "My Opinions are just that." ################################################################ 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 ################################################################