Electronics Forum | Wed Feb 22 08:01:42 EST 2006 | INGE
We have a new SMT line, our customers are asking us the validation of the process. Not only the validation of the resulting assembled board (solder joint...) but also a validation of every single machine in the line (ex. stencil printer...). For exam
Electronics Forum | Wed Oct 04 11:36:06 EDT 2006 | flipit
Hi, Anyone ever have an issue with stray capacitance when using no clean solder paste. We are having a timing problem on one product. The problem goes away when we clean the assemblies. We use a no clean process normally. These assemblies worked
Electronics Forum | Wed Feb 14 10:10:55 EST 2007 | rob_thomas
The challenge regarding the stencil was mostly due to the actual board layout and nothing having to do with the voids in the solder. It was my first encounter with 0.5 mm pitch on BGA and dealing with a LF solder paste with higher viscosity than tha
Electronics Forum | Thu Feb 15 10:40:27 EST 2007 | phil69
Hi All, I was wondering if anyone has experience of printing solder paste on to 2x2" ceramic substrates.. At present we are using a very old de haart printer with a mesh emulsion screen.. I am looking to replace this with a more reliable mo
Electronics Forum | Fri Jul 11 15:47:54 EDT 2008 | hegemon
We used these same type of parameters regardless of the QFN package size. We used componentes that ranged from 3x3mm to 12x12mm Same idea. The reduction in solder paste for the center pad is the key. Too much, and you wind up with no connects at the
Electronics Forum | Mon Nov 26 20:11:41 EST 2007 | shy
Yes, i'm agree with you davef but i'm not put the chipbonders onto pads. i'm put the chipbonders at the beneath component (center between both component terminals) which the idea is to hold the component during wave soldering which might cause the co
Electronics Forum | Thu Jun 26 09:09:27 EDT 2008 | kmeline
The pad size is okay. I have also requested the manufacturer's recommend reflow profile. I have seen some issues with 0402 caps that we run also but for the most part solder paste does okay. I think the cap issues is stencil related. Still trying to
Electronics Forum | Tue Jul 08 15:37:14 EDT 2008 | realchunks
Volume that appears to be caused by wetting. Now remember most solder pastes will not "flow" across an entire pad. It will only flow where it is printed. In your pic, if the pad was covered and came out like this - it may be your pad. If it was
Electronics Forum | Mon Sep 01 09:49:54 EDT 2008 | allan99
I told a friend this problem, and he also thinks the problem is the component, and suggested a different solder paste (more acid), maybe you can ask your supplier for a sample and orientation. Until there I think you have to rework if its only one co
Electronics Forum | Thu Feb 05 02:34:05 EST 2009 | sachu_70
Hi Manuel, most passives are chip components. These tend to self-center/align during the reflow process. However, you need to ensure that there is a uniform balanced solder paste deposit. I had tried few such ovals in earlier stencil designs and resu
