Electronics Forum | Mon Mar 03 11:07:40 EST 2003 | MA/NY DDave
Hi In addition to what DaveF gave you which you should look at first Search the archives for warp bow twist warpage etc. A Lot of treads exist. Many of the larger OEM's and even the Mil have historically created their own documents for acceptable
Electronics Forum | Thu Jul 31 15:29:25 EDT 2003 | bcceng
A couple of things you can look into 1. The proper bottom pre-heat of board. If you are applying only direct hot air to BGA without preheating can cause BGA's to warp and collapse un-even. 2. Moisture on you BGA's. If BGA's were not properly packa
Electronics Forum | Thu Dec 18 23:44:53 EST 2003 | Dean
...don't expect high yields with hasl on that device. Yeah, you an do it. But not reliably. Also, factor in board warp, bump tolerance AND HASL variation....recipe for disaster. can your process toleate a selective gold on the one device? How ab
Electronics Forum | Mon Jan 10 08:56:19 EST 2005 | John
Does anyone know whether it's possible, given a copy of OS/2 Warp 4, and the Universal software, to set up a standalone box, not connected to the machine itself, in order to do programming, etc, faster? I've got the feeling it is, but I'd hate to in
Electronics Forum | Thu Jul 07 17:59:58 EDT 2005 | russ
I have found that if you place it "upside down" with the paper on the bottom they work very well also. The paper has a tendency to warp during heating which causes the no connects. by adding flux to the preform you are essentially sticking the pref
Electronics Forum | Thu Mar 17 11:07:08 EST 2005 | Dougs
I'd agree with Justin, we do double sided reflow on most of our boards with fine pitch QFP's both sides, you do have a problem somewhere else, what size is you board? Is it warping slightly? What kind of oven are you using? Is it convection? fans
Electronics Forum | Thu Apr 14 13:53:39 EDT 2005 | jdengler
The board warp is a good place to look. Also: -Are you pre-rotating? -Are you using the largest nozzle possible? Most of the time this ends up being a component slip on the nozzle caused when the part is rotated if not doing pre-rotate, or slippa
Electronics Forum | Thu Aug 04 16:34:03 EDT 2005 | bhu
You haven't mentioned whether you are producting only through hole product or if it is mixed technology. What kind of flux (no clean, H2O clean) you are using and whether you performed a first article at part stuffing prior to wave. Generally, you
Electronics Forum | Fri Jul 22 16:42:50 EDT 2005 | campos
hello all, I�m experiencing problems with "warped" boards after first reflow, some of them i just can�t print side two due to this problem,,is it related only to reflow? i�m using a linear profile (225� peak / 70s time above) with a tin lead paste,t
Electronics Forum | Wed Aug 03 04:33:39 EDT 2005 | aj
if you have enough free space at the edge of the board you could try some titanium supports, I have to use these on some products to prevent warping. Also, in relation to profile and I know there are a lot of variables to consider but is 225 not a b
