One of the factors that can affect thermal cycling results is if the boards are tested after assembly and rework, or tested "as received". Materials may be degraded with the thermal excursions of assembly and rework (particularly lead free). Also understand that boards fabricated with sequential lamination can have reduced performance because internal material layers have already been exposed to 2 or more thermal cycles in fabrication. Sequential lamination would be typical fabrication method on boards with buried or blind vias. Paul Reid Program Coordinator PWB Interconnect Solutions 613-596-4244 ext. 229 -----Original Message----- From: Colin McVean [mailto:[log in to unmask]] Sent: Wednesday, February 02, 2005 12:22 PM To: [log in to unmask] Subject: Re: [TN] Behavior of Via's in low temperature cycling You may want to try the PCL370 HR product, which is more robust. Also check degree of cure on the Turbo just to make sure. Call the Tech Service guys, for help on the press cycle, and they'll check the sample for you Colin McVean Production Manager Artetch Circuits Limited Tel: 01903 725365 -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Richard Kraszewski Sent: 02 February 2005 17:12 To: [log in to unmask] Subject: Re: [TN] Behavior of Via's in low temperature cycling The material has a high Tg I believe in the 180 range and we had barrel cracks but no cracks in the layers. The laminate material is a Polyclad 370turbo with a 2 ply core 8 mils thick with 6 layers. We cycled at 120 to -45degC . Failures were observed round 300 cycles of 125C to -40C. Thanks for the interest in my situation. Rich K/ KEDS -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Susan Mansilla Sent: Wednesday, February 02, 2005 7:42 AM To: [log in to unmask] Subject: Re: [TN] Behavior of Via's in low temperature cycling The test you describe is not a difficult test for today's product to meet - do you know what type of failure you have? Corner cracks, barrel cracks, inner layer separation????? The Z-axis expansion of the laminate puts stresses on the laminate system and the plating system. Do you know what materials went into building the board (Tg etc)? Susan Mansilla Robisan Lab --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------