lab@fibercom.UUCP (Lance Beckner) (06/20/89)
Can anybody give me some info on how to best eliminate warping that results when a PC board goes through flow soldering? We have a good number of eight layer boards (6.3" X 9.2" X .063") and so far, every one has come out warped. Other than just playing around with solder temperature and time, is there anything I could/should do? Please E-mail me any suggestions, and I'll post a summary later. Thanks in advance. -- Lance A. Beckner INTERNET: lab@fibercom.com FiberCom, Inc. UUCP: ...!uunet!fibercom!lab P.O. Box 11966 FAX: (703) 342-5961 Roanoke, VA 24022-1966 PHONE: (703) 342-6700
waltm@maxzilla.Encore.COM (Walt Mattison) (07/07/89)
In article <753@fibercom.UUCP> lab@fibercom.UUCP (Lance Beckner) writes: > >Can anybody give me some info on how to best eliminate warping that >results when a PC board goes through flow soldering? We have a >good number of eight layer boards (6.3" X 9.2" X .063") and so far, >every one has come out warped. Other than just playing around with >solder temperature and time, is there anything I could/should do? > >Please E-mail me any suggestions, and I'll post a summary later. > >Thanks in advance. >-- >Lance A. Beckner INTERNET: lab@fibercom.com >FiberCom, Inc. UUCP: ...!uunet!fibercom!lab >P.O. Box 11966 FAX: (703) 342-5961 >Roanoke, VA 24022-1966 PHONE: (703) 342-6700 Lance, Warpage is a common problem with board assembly and is always curable. First the boards you are talking about are not that large so a board thickness of 0.063" is not a problem. Do these boards have tooling holes at each corner? Tooling holes or some other type of secure fastening method must be used to firmly attach the board to a sturdy fixture for wave soldering. This fixture will keep the board from warping during the actual wave process. Remember that enough fixtures must be built so that you can allow the boards that have been waved to cool to room temperature slowly while still firmly in the fixture. Fixturing is the key to reducing warpage in wave soldering, temp and time are contributors but play a much lower role than fixturing. Are you doing these boards in-house? Why don't you just send them out to be waved and not worry or does your company own the equipment to do it infrequently? If you have any problems or questions with this feel free to call, I will give you a hand. Walt Mattison Phone 508-460-0500 Fax 508-485-0709