Electronics Forum | Fri Jan 24 08:14:24 EST 2014 | davem
m_imtiaz, Over the last 15 years or so I've found that using the stencil foil thickness +2mils/-0mils has worked very well. For example, if you have a 5mil stencil thickness your upper control limit would be 7mils and your lower control limit would
Electronics Forum | Tue Jan 07 23:38:08 EST 2014 | m_imtiaz
want to know the tolerance the paste height in the solder paste printing. for example if stencil thickness is 7 mil, what will the acceptance level of paste height ( upper and lower) kindly share if any guidelines or formula for the same
Electronics Forum | Mon Mar 02 11:27:51 EST 2009 | wrongway
Check stencil is their a lot of paste still on the stencil if so that is the extra thickness maybe add more pressure. check to see if board is coming up far enough to touch the bottom of the stencil.
Electronics Forum | Tue Feb 22 01:38:42 EST 2005 | JSS
We r using QFPs of 0.5mm pitch and r not getting any soldering prob at the end.But some new customer insists upon the thickness check of the solder paste after printing. At present we don't hv thickness checking system.We r controlling the amount of
Electronics Forum | Mon Feb 21 02:02:54 EST 2005 | JSS
First of all THANKS for thr reply. I totally agree with u that paste dried,stencil aperture clogged like probs comes during the production but we hv a visual inspection stage (with 5X illuminated lamp)after printing process and before inserting the
Electronics Forum | Wed Mar 04 15:26:07 EST 2009 | clampron
Hi Jorge, Take a bare board and measure over the same pad. We have had similar issues with a higher deposition than the stencil thickness. In some cases, we have found that the top of the pad was higher than the solder mask. Our inspector uses the b
Electronics Forum | Mon Feb 21 03:51:37 EST 2005 | abhirami
Solder paste thickness control is more important in SMT process. What controls do you have? I guess if everyone follows the critical control path, then there are always reduced problems. The issue is no one is perfect. Paste tends to be on the stenci
Electronics Forum | Thu Mar 31 07:56:31 EST 2005 | cn
I agree with chuck, but would like to add. 2D is a great option and helps to keep your printing process in check, it will measure the x & y coverage on the pad. It will help you determin when your stencil aps become clogged or when the bottom of your
Electronics Forum | Wed Jan 08 08:20:52 EST 2014 | emeto
To most of our boards I give 20-30% tolerance in both directions. From experience if you have big aperture on your stencil, the squeegee will scoop certain amount of paste from this aperture and you will see lower height. Depending on your board supp
Electronics Forum | Tue Dec 11 19:48:37 EST 2007 | arun2382
Hi, If I were working with a 75 um thick stencil, Is there a spec. as to what the maximum value allowed on actual solder height measurements? Stencil type: Laser cut and electropolished Solder paste type: Type 4 Sn-Sb Would the measured values va
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