Electronics Forum | Thu Aug 29 13:03:13 EDT 2002 | lysik
You have may have already checked this but verify stencil design (aspect ratio) and make sure you are using the correct paste (mesh size) Also look at perint pressure. up to 2 lbs per inch of blade used. You may also want to use a slow break away whe
Electronics Forum | Wed Jul 13 09:07:32 EDT 2005 | russ
The reason for going 1:1 with lead free is that it does not spread out like the pb solders. So 1:1 is really not necessary in my opinion. We go 1:1 anyway on discrete components along with other packages. You always have to make sure that the area
Electronics Forum | Mon Oct 17 11:16:09 EDT 2005 | slthomas
There are a lot of things that might affect your cleaning efficiency. Paste type (no clean or w/s?), cleaning chemistry, aperture aspect ratio (aperture width/stencil thickness), "linty" wipes, etc. Another thing you need to look at is the frequency
Electronics Forum | Thu Dec 08 12:24:11 EST 2005 | cyber_wolf
Any good stencil house should be able to recommend the proper configuration on a fine pitch aperture design. They can also advise you as to which foil thickness works best. The norm foil thickness is .005" - .006". There are always special instances
Electronics Forum | Mon Mar 27 20:53:12 EST 2006 | davef
If you believe: * There is air in your paste AND * You are not whipping the air into the paste ... You should: * Return the paste to your supplier * Get it replaced * Begin qualifying a replacement supplier. One thing before you go racing off to ly
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 | Tue Aug 01 10:29:43 EDT 2006 | slthomas
It's been a while since I've built with 16 mil pitch, but I have to second the recommendation to go to 5 mil stencils. Night and day as far as release characteristics. The increase in aspect ratio opens up the window a lot. (read = covers up a mult
Electronics Forum | Tue May 22 12:27:04 EDT 2007 | cyber_wolf
I would consider calling Kester and telling them they need to send their people out. I could not really see mesh size being an issue on anything 20mil and above. There are several other issues that can cause aperture clogging as well...: Incorrect
Electronics Forum | Mon Feb 25 12:21:16 EST 2008 | stevek
Rather than having the artwork cover the via as with tenting dry film, and letting the mask do what it will, the preferred way is to do a second op silk screen with something like SR1000 just in the vias themselves to plug them. This doesn't always
Electronics Forum | Wed Apr 14 14:51:10 EDT 2010 | jgalarza
After checking some of our stencil data for the correct aspect ratio I found that a few are wrong. I would like to change them from 5mil thk to 4mil thk but do not know how much paste volume I need to keep. We are using 0201,0402, and BGA with 0.80 p
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