Electronics Forum | Fri Jun 24 07:02:35 EDT 2005 | davef
Problem 1: Solder shortage * Stencil aperatures [except the heat slug] should be 1:1 with the board. * Stencil should be 5 thou thick laser cut. * Board should be 1:1 with the component * Print should look good. Problem #2: Bad connection between p
Electronics Forum | Tue Feb 09 16:53:06 EST 2021 | SMTA-64387083
The size of the pad changes among the two. A solder mask defined pad will always be larger than a copper defined by your mask expansion setting. This will affect paste volume, if your standard paste aperture is designed for copper defined pads you m
Electronics Forum | Mon Jan 13 17:39:49 EST 2020 | avillaro2020
Hi, I need help on how to address the solder wicking on the samtec searay connector after reflow resulting to open solder joints on thick and thermal heavy PCB (4.4mm and 6.3mm). I increased my solder paste thickness to 8 mils, the connector is manua
Electronics Forum | Thu Jun 28 17:05:46 EDT 2012 | davef
Here’s what we seem to know: * There’s a problem with voiding in the solder connections of SMT capacitors * A void is an open area caused by air or process fluid that is trapped within a solder connection * Voids are an allowable condition as long as
Electronics Forum | Tue May 07 10:36:38 EDT 2019 | slthomas
Probably just means you started out with an optimal profile. I suspect that not everyone does. ;) It seems like we did have some luck with profile adjustments in one instance with some QFN's with a large thermal pad. Like I said, though, the profi
Electronics Forum | Sun Nov 14 20:33:39 EST 2010 | isd_jwendell
Hopefully you have a dispenser on your machine so that you can add a few large dots of paste to the thermal pad.
Electronics Forum | Tue Nov 09 04:21:11 EST 2010 | bising
Hi SMT World, I am facing a technical challenge related to an SOIC 14lds with thermal pad on it's belly that needs to be soldered onto PCB, together with leads. It is a 50 per board, expected 80% solder load on every one. We have some units without
Electronics Forum | Wed Nov 10 16:19:51 EST 2010 | davef
The 5 thou standoff of your SOIC is probably the minimum. We wouldn't be surprised to see 10 thou. With this, you could have maybe a 6 thou gap between printed solder paste and the bottom of the heat slug. So, you're expecting the rabbit ears of p
Electronics Forum | Tue May 28 18:31:08 EDT 2019 | jlawson
Solder paste flux is main contributor, Lead termination chemical-oxide by products and PCB Plating-Chemicals. Reflow profile would have very limited if not no impact really unless is way off. Paste volume control and Stencil design plays a big part
Electronics Forum | Thu May 30 09:33:15 EDT 2019 | emeto
Contributors in order of importance: 1. PCB design - if you have large thermal pads, a grid of via holes should be created. Components with low profile will not let the gas to escape from the joint. The only way is going down. 2. Reduce paste volum
