Electronics Forum | Wed May 08 04:20:58 EDT 2002 | S.E.J.E
Hi there. I intend to do some evaluation between different pastes, stencils, stencil apertures and reflow profiles (to find practical differences, evaluate stencil suppliers and have some desing guides among other things). I'm considering to use ben
Electronics Forum | Tue Jul 13 13:28:18 EDT 1999 | Upinder Singh
| | Hi all , | | | | We are trying to implement the micro-BGA technology at our plant. I need the clarification to the following points: | | | | 1. Is underfill required for micro-BGAs? | | | | 2. What type of stencil apertures are the industry st
Electronics Forum | Fri Aug 04 07:44:09 EDT 2006 | aj
Hi, Have you incorporated any Aperture Modifications in your stencil.( i.e. Homebase / 10% reductions). I have a similiar problem here with one of our high volume builds and I am in the process of ordering a new stencil with recommeded aperture red
Electronics Forum | Wed Feb 04 08:00:30 EST 2009 | milroy
Hi, It depends on the stencil thickness, aperture size and the component footprint. For exampl if you have a PCB with QFP,CSP,QFN & BGA parts then this underwiper is not useable because you will still find solder cream deposits in the apertures aft
Electronics Forum | Wed Nov 15 12:52:21 EST 2017 | georgetruitt
IMO – Look into nano-coatings for your stencil and radius all square apertures This should help out with solder paste releasing from the stencil helping with insufficient solder QFN LGA aperture design, try a stencil cut with a few different apertur
Electronics Forum | Mon Aug 13 12:38:38 EDT 2012 | grahamcooper22
Maybe the area ratio between the sides of the stencil apertures and the aperture opening is too low for the spec of the paste ? So it will tend to stick in the apertures. ...only solution is thinner stencil or a paste that can release easily when are
Electronics Forum | Mon Sep 20 17:46:21 EDT 1999 | Dave F
| I've had some trouble pasting a test board for a MicroBGA trial. Most of the paste remains in the stencil apertures. | The stencil is 6 mil thick, laser cut and electo-polished. | The apertures are 12 mil in diameter with 20 mil pitch. | We are usi
Electronics Forum | Wed Sep 01 13:51:38 EDT 1999 | Dave F
| Planning to evaluate the above process... | Can anyone can give me some tips/infos on the above.... | e.g. stencil aperture design, aperture ratio, common problems and solutions they encountered on the above process, is the profile different from a
Electronics Forum | Thu Dec 15 11:06:05 EST 2005 | Samir Nagaheenanajar
You might wanna try a small reduction in your stencil aperture. For example, for a 30-mil pad go 26-mil square aperture with 8 to 10-mil radius on your corners. Also, look at your designs. Is there enough resist between your pad and ball? Another
Electronics Forum | Wed Dec 13 16:47:41 EST 2000 | Michael Parker
It is apparent that you have evaporated the flux before you reflowed. You got lucky when the paste slumped and you didn't get major problems elsewhere. A more reliable solution is to adjust the stencil apertures for the part that is experiencing bri
