Electronics Forum | Fri Sep 02 16:22:37 EDT 2011 | ttaubert
Are there SMT mechanical components like that could be used for orientating PCB-level optics on the board and do not require holes in the board? Their final position would solely depend on the reflow. A height of 1/8" would be sufficient. I was con
Electronics Forum | Sat Feb 02 07:07:47 EST 2013 | bandjwet
The keys to avoiding the voids we have found are: 1. Proper reflow profile 2. Proper stencil design 3. Prebumping using either a metal stencil or StencilMate stencils (and then using paste flux to attach later) http://www.solder.net/products/stencilm
Electronics Forum | Wed Mar 27 07:01:26 EDT 2019 | charliedci
200uM seems high. I say this because typically our solder stencils in this application are between 80uM and 100uM thick which would leave the component height less than that after reflow. However if your not experiencing any shorting between pads I w
Electronics Forum | Mon Mar 25 21:50:10 EST 2002 | davef
Some of this was copped from Fred. There are numerous package types that now fall under the rubric of land grid array [LGA]. Land grid devices [ie, Bumped Chip Carrier� [BCC], LGA, Quad Flat-pack No-lead [QFN], MicroLeadFrame�, etc] are essentially
Electronics Forum | Fri May 07 17:04:02 EDT 2004 | davef
Either method is acceptable: * No IPC approved method * Applying flux only is easier than applying paste * Paste gives a higher stand-off, which should improve reliability
Electronics Forum | Wed Mar 16 02:06:13 EST 2005 | amstech
What is the joint stand-off gap anticipated after the board level assembly and reflow? If it is designed per CSP standards, there should be no issue in water cleaning. If the gap is 90 � 100 micron, better to go with a no clean paste. His needs good
Electronics Forum | Mon Oct 31 13:31:19 EDT 2011 | davef
We're not sure what a 'sticky roller' is, but will it: * Remove ionic materials * Leave no residue * Clean the walls of through holes and vias * Clean under low stand-off BGA and LGA
Electronics Forum | Tue Jun 01 10:00:45 EDT 2004 | davef
We agree with John. It's possible to clean under 1.27 and 1 mm BGA. These devices have a reasonable stand-off that allows cleaning of water soluable flux residues with modern cleaners. So, if you have process problems with low-res fluxes, what mak
Electronics Forum | Thu Sep 22 10:28:48 EDT 2011 | davef
We agree with you. Recognize that these new solder connections have less metal and a lower standoff than similar BGA solder connections that have not been reworked. This could reduce the reliability of your product, somewhat. Flux or gel may be use
Electronics Forum | Tue Oct 06 13:46:35 EDT 2015 | deanm
Agree. However the LGA has an even lower standoff, so I would think it would be an even greater challenge. The LGA is a cheaper choice but want to know from those who have done both if the extra cost of the SnPb BGA would pay for itself in lower rew
