Electronics Forum | Wed Jun 16 07:35:28 EDT 2010 | scottp
Rather than tent the thermal vias, we use a small annular ring of soldermask around them and only print paste in the areas between the vias. Any way you go you're going to have voids under QFNs, so we just try to make it repeatable so our designers
Electronics Forum | Mon Aug 23 10:11:55 EDT 2010 | flipit
Hi, I have never been able to find an acceptable dispense process for dispensing small dots of solder paste. I currently have an auger screw automated dispense system and can not accomplish 0.010" dot sizes. In addition, stencil printing is much m
Electronics Forum | Fri Feb 01 19:07:57 EST 2013 | hegemon
We have had some success in void reduction with LGA by pre-tinning or "bumping" the devices before placement. The extra solder seems to allow a slightly higher standoff, and allows better outgassing, is my guess. A lot more labor , but the results
Electronics Forum | Wed Jul 30 11:36:31 EDT 2014 | emeto
About the pads shape - you can do rectangular or oblong. For stencil design oblong is better for small pads(0.2mm) because it will give better release, so having this thought in mind you should probably design oblong shape and then print make paste a
Electronics Forum | Mon Jul 13 11:33:54 EDT 2020 | spoiltforchoice
Well obviously the answer is yes. Most people would probably do it in their CAD package. If you want to use a third party tool Fab3000 does tis as well as a whole bunch of other things you might possibly want to do when processing files supplied by o
Electronics Forum | Thu Apr 19 11:04:43 EDT 2001 | Spanky
All, We are getting ready to start running with 0201 passives. I have never run these before. We have run some 0402s however. We don't have any assemblies in-house yet, so I can't give any intelligent information regarding the board design (size,
Electronics Forum | Fri Nov 13 14:43:36 EST 1998 | Dave F
| | | | I keep hearing about polyimide stencils, but what are they like in terms of registration and aperture accuracy? | | | | | | | Fraser- | | | | | | We use polyimide stencils with great success for our prototype boards. They are cheaper a
Electronics Forum | Wed Sep 19 14:23:31 EDT 2001 | jschake
Pad Metallurgy Used: Copper OSP pads were used for all of the results that I have been reporting. The same design test boards with Nickel/Gold pads are available and awaiting further assembly tests. I will consult with a board technology and metall
Electronics Forum | Fri Nov 23 14:47:35 EST 2001 | kgroen
Some comments on the previous post: Be careful when looking at the proportion of SMT defects that are solder defects - you may very well find that only a small few of them originate at the screen printing step. As for specification limits for pas
Electronics Forum | Sun Mar 04 02:39:27 EST 2012 | eadthem
I don't have our DEK printer part numbers memorized, In general we have a older machine running NT4.0 . It has 2Di inspection but we never use it because you can only inspect/setup 1 camera shot at once, making for very long programming. Our newer D
