Electronics Forum | Fri Aug 22 09:50:20 EDT 2003 | Mike Snider
I am placing a plastic Cypress, 256 pin BGA on a small assembly, and I cannot stop the corners from bowing. I've moved my profile up and down with no results. Any suggestions?
Electronics Forum | Thu Jan 15 15:08:43 EST 2004 | mrmaint
Are your qfp's being stored properly. I have seen this in the past and it turned out to be a moisture issue. We saw most of the problems on the corners. The component would swell during the reflow process thus lifting the corners. After baking the re
Electronics Forum | Wed Jan 14 18:33:21 EST 2004 | ex maintain leader
qfp tray one corner on the holder is 45 degree cutted there is the pin 1 bga also one corner is different in the tray at tape packaging I'm not sure, I have seen diferent comissions belong supliers
Electronics Forum | Mon Jan 21 18:57:02 EST 2008 | davef
We think maybe 50 thou would be a more approachable corner radius. Why does your customer want to have radiused corners?
Electronics Forum | Mon Jun 13 01:38:59 EDT 2011 | kenneth0
Hello Steve, i think you are experiencing the potato chip effect, where temperature difference at the center and edges are huge; causing BGA edges to tilt down or up.Try narrow down the temperature difference between the center of BGA and corner. I
Electronics Forum | Fri Aug 05 14:31:43 EDT 2011 | dmiller
Try a probe at two corners (opposing) and one on top. Provided your corners are getting comforatably into reflow temperatures, the middle should as well.
Electronics Forum | Tue Mar 21 20:36:11 EST 2000 | Dave F
Armin: Boca makes some good points about release. So, let me spin this up from a different angle ... SM-782 suggests "full radius corners" as an alternative to the more familiar square corner pads on PLCC, TSOP and QFP. We see both also. We thin
Electronics Forum | Wed Jul 31 07:51:31 EDT 2019 | ameenullakhan
Hi Dave, lead is 80Pb/20Sn. Top joint off CCGA lead is SN63/Pb37. Thermocouple was placed at center lead of the CCGA and one at the corner lead of CCGA. Ramp Rate Center 1.09 Corner 1.26 Soak ( 140 - 160 deg C ) Center 37sec Corner 38sec Ref
Electronics Forum | Thu Jun 22 11:21:59 EDT 2000 | Chrys Shea
My personal opinion: Use 20 mil squares with the corners radiused at 5 mils. The squares offer 2 benefits: 1) A little more paste, which makes for a higher diameter solder column that is more reliable 2) Better stencil release of the paste. It's e
Electronics Forum | Mon Mar 20 20:22:47 EST 2000 | Dreamsniper
We used to have our PLCC,s, TSOP's and QFP's (0.65 mm pitch) Land Patterns designed in square corners. Some of our products have them designed in Full Radius Corners. As of now, with the two different designs running in our production floor, we can't
