Electronics Forum | Tue Sep 25 15:48:34 EDT 2001 | mparker
Scavenge all the old solder off the board and the chip. Micro screen paste to the chip. As far as thickness, check your aspect ratio to determine the spec. Eliminate just one variable at a time to get to the root cause. Start by not using the tacky
Electronics Forum | Tue Aug 01 10:09:52 EDT 2006 | cyber_wolf
Chunks, Make sure your aspect ratio is OK. Normally for an application like this, I would use a .005 foil. The foil material would be invar.The invar has better release characteristics. Crappy solder paste can also cause release issues. I am not sur
Electronics Forum | Fri Mar 02 10:06:28 EST 2007 | oldsmtdude
Agilent SP50 rocks for continuous improvement and pass-fail efforts. You'll see variation you never imagined you had prior. But be aware you absolutely have to monitor data and tweak your processes to improve results. Do not jump in and try and use
Electronics Forum | Fri Aug 13 18:38:47 EDT 2004 | russ
Your paste manufacturer will have the best guidelines for you. Different paste types and manufacturers sometimes/usually require a little bit different setup. I would also contact your printer manufacturer. As far as stencil concerns the larger/be
Electronics Forum | Tue Oct 10 12:56:15 EDT 2000 | Ken Van ZIll
I agree that homplate is a good design, but also this could be caused by the stencil thickness and aperture size, if you are at 7-9 mils thick stencil and a 1:1 ratio on aperture size then 2 things i know of will happen, one a squishing out of past o
Electronics Forum | Sat Dec 08 00:09:24 EST 2012 | jlawson
Mentor(Valor) has dfm softwares that not only looks at the stecnicl layers buy can look at other impacts that could effect the optimisation of the stencil design, ie solder mask layer tolerances defined from fabricator-design etc - this is a upper en
Electronics Forum | Tue Dec 23 17:34:07 EST 2008 | davef
We hear you talking two main issues: 1 Solder paste release 2 Thoughts on using two passes of solder paste on the stencil 1 Solder paste release * Check your aperture & aspect ratios [Search the fine SMTnet Archives for more] * Do a better job with
Electronics Forum | Thu Sep 30 06:47:51 EDT 1999 | park kyung sam
| My stencil thickness is 6 mil and we got qfp's with fine pitch. | how many percent should i reduce my stencil aperture using a 6 mil stencil for 0.5 mm pitch and 0.4 mm pitch ? | | thanks | we have placed 16 mil components for 3 years. why don't
Electronics Forum | Mon Aug 30 04:08:51 EDT 1999 | Earl Moon
| | 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
Electronics Forum | Wed Mar 21 16:32:03 EST 2001 | mparker
The root cause is dependant on the type of solder "splash", ball, whatever, that you are seeing post reflow. If it is smears, then cleaning the stencil underside is probably the answer. Are you using automatic wipers? How many print cycles between w
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