Question for the PCB fabricators... One of our PCB suppliers is asking us to accept PCBs with a "minor" issue. The problem is described as this: The panels were under-developed and some residual solder mask was left over. To eliminate this, the panels were put through a second pass to ensure all residual solder mask was removed. The result is some overdevelopment of the solder mask. Then, this apparently resulted in an "undercut" along the demarcation lines. They say during a tape test, very small traces of mask from the undercuts comes off. The mask is still present between all features and is adhered to the PCB. But, it is over-developed and has undercuts. They say that while it does not pass the tape adhesion test, it is of no detriment to the PCB quality or performance. My question is if over-developed soldermask maintains the same properties as normally developed soldermask? When I asked about this, they said the properties of the mask are determined by the initial (pre-developing) cure and the final (post-developing cure), and the over-development does not affect the properties. True? In case "it depends", these PCBs are used in avionics power supplies. Thanks in advance! Kevin --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 -----------------------------------------------------