We had some boards with a warpage problem. MFRing made up some fancy board carriers that held the boards flat during the process. Also, they may have tweaked the process (temperature profiles etc.). I don't know which (if it was either of these) fix actually solved the problem.
At 12:00 AM 2002-04-04 -0800, you wrote: >A number of different ways to even out copper coverage on layers on >opposing sides of board were mentioned, and these are probably aimed >at solving residual stresses left in the board. That sounds good, but may >be difficult to accomplish, dpending on board density, etc. > >One thing that comes to mind is that the boards come out of the laminating >press flat, go through all the additional steps in PCB fabrication OK, but >then warp when YOU process them to attach components. Are you sure >you have to heat the boards as hot, for as long as you are doing, to get >good soldering? That may have something to do with it. > >Finally, could you give the boards some mechanical support during the reflow >soldering? Making some simple metal frames that hold the board edges >during the entire time it is heated might keep them flat as they cool. > >Jon > _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/[email protected] * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
