Electronics Forum | Mon Sep 13 04:11:27 EDT 1999 | Earl Moon
| | hello | | | | having a problem with one customers bare boards not matching my stencil apertures. i design stencils based on gerber data and reduce up to 15% on some pads. do some board houses reduce pads after receiving gerber data???why would
Electronics Forum | Thu Apr 06 00:27:42 EDT 2000 | Dean
I would check their data sheet for the particular product. Thats the range I have for Some Kester products I use... Are you seeing any slumping prior to pick-and-place? Is the bridge in the same place every time? How is your pick-and-place mounting
Electronics Forum | Thu Jun 16 22:14:51 EDT 2005 | davef
16 thou pitch parts: Use a 5 thou laser cut electropolished stencil with 0.008"x0.045" apertures and type 3 solder paste. Bridges Connecting or Partially Connecting Adjacent Leads or Lands * Excessive solder paste * Excessive component placement pre
Electronics Forum | Thu Apr 06 08:31:13 EDT 2000 | D Scott
Angela Do you see this problem on other .5mm pitch devices or is it only on the QFP? Check placement height, too low or to high can cause you problems Pad co-planarity, are your boards HASL? Is your board sagging during placement(board supports) An
Electronics Forum | Thu Jun 16 08:31:15 EDT 2005 | jh0n!
The most part I have the most difficulty with is a 16mil QFN. We found that reducing stencil thickness to 4mil, and reducing aperatures for the IC by 20%, and setting local fiducials to the IC helped immensely. We used to get 75% or more bridged ou
Electronics Forum | Tue Sep 18 12:10:39 EDT 2007 | wailiang81
Hi, good day to all. This is my 1st question post in this forum. Hope able to share some knowledge here. As we know QFP area like 0.4mm pitch was a very critical area to control especially those PCB using silkscreen printing process manufactured. Onc
Electronics Forum | Fri Sep 24 10:57:18 EDT 1999 | Earl Moon
| Hi Folks: | | We've been having bridging problems on our fine-pitch QFP's, despite thorough inspection of paste height, volume, and placement accuracies....profiles look good also. | | The bridging is happening after coming out of reflow...one la
Electronics Forum | Mon Feb 22 19:22:40 EST 1999 | Steve Gregory
| A rash of new products here at my company have designs with multi-pin connectors 90 out-of-phase (orientation)wiht respect to wave direction, which has lead to massive bridging (shorts) problems.... | | Does anyone still use the 45 Degree Pallet
Electronics Forum | Tue Jul 17 15:13:53 EDT 2001 | mparker
Dave - I agree that the U shape for QFP's sounds a bit whacked, for the reasons you state. It may work OK for larger pitchs but then again there are a myriad of fixes that work before resorting to U shapes. With the U shape removing paste from under
Electronics Forum | Mon Dec 13 05:43:27 EST 1999 | Wolfgang Busko
Hi Steve, 20 mil pitch shouldn�t be that problem nowadays. In your case bridging and poor wetting seem to go hand in hand. For the poor wetting try to eliminate it by using different paste (higher activated) and work on your profile. Coplanarity also
