This is not a normal process. I would think that chemical etching is more affective in removing metals and oxides from the resin surface. We see no issues with SIR/MIR using standard PCB processes. I have done this in the past of flex to promote stiffener bonding and mask adhesion. Possible the PCB house has an issue with chemical etching or base materials. Jeffrey Bush Director, Quality Assurance and Technical Support VERMONT CIRCUITS INCORPORATED 76 Technology Drive - POB 1890 Brattleboro, Vermont 05302 Voice: 802.257.4571.21 Fax: 802.257.0011 http://www.vtcircuits.com -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Ivanoe Pedruzzi Sent: Tuesday, September 06, 2005 9:35 AM To: [log in to unmask] Subject: [TN] Sand blasting pcb after copper etching Dear Technetters, I'm not familiar with the process of making pcb and I would like to have your comments on something I was told from a pcb maker representative. "...in order to ensure a well insulation between traces, we do sandblasting (very little and tiny) pcb's after etching. this is to remove the bonding material that remains on the board after removing the copper. This is the only way to achieve a very good SIR result." Is this a normal procedure, was he correct in his claim? Thanks, Ivanoe Pedruzzi --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------