Electronics Forum | Thu Jul 19 22:52:43 EDT 2001 | davef
Most paste manufacturers talk about a 12 month shelf life for paste. They give the user half of that time. The remainder is used-up in processing and distribution. We'd give it a shot. You paste supplier should be able to give you a much clearer
Electronics Forum | Tue Sep 21 11:28:26 EDT 1999 | Dave F
| I've had some trouble pasting a test board for a MicroBGA trial. Most of the paste remains in the stencil apertures. | The stencil is 6 mil thick, laser cut and electo-polished. | The apertures are 12 mil in diameter with 20 mil pitch. | We are usi
Electronics Forum | Sat Aug 14 08:43:17 EDT 2004 | davef
Russ makes good points. Your printer supplier can give good advice on machine setup also. We know we're printing well when: * Paste at least as big in diameter as your thumb is rolling across the stencil * Paste is filling the apertures * Squeegee
Electronics Forum | Thu Mar 20 09:55:11 EDT 2008 | swag
We have a class 3 SMT build that requires the paste conforms to J-STD-005 RE LO. We have not used a low activity flux in the past and would prefer not to have to change our wash process or change to no-clean paste for these builds. I have researche
Electronics Forum | Mon Oct 15 10:57:32 EDT 2001 | davef
Before this wave solder pallet salesman blather gets too far out-of-control, let�s stop for a minute. The three major approaches you have are: 1 SELECTIVE SOLDERING: Using: * Specialty wave soldering machine to solder specific areas of a board * P
Electronics Forum | Tue Aug 17 14:34:27 EDT 2010 | davef
Comments are: * Too much paste ... reduce it more. * Do not let a traces run between small discrete pads or the heat of reflow will pull a ball to the trace, we can repeat this. * Change the placement height on chip parts to reduce solder spread / mu
Electronics Forum | Mon Jan 12 02:45:53 EST 2009 | sachu_70
Hi Stefano, Although your concept of Wave soldering such devices is possible, I would look at an alternate solution. An easier way would be to Reflow solder all Bottom side SMD components with solder paste, followed by wave soldering for only through
Electronics Forum | Wed Feb 21 16:14:44 EST 2001 | billschreiber
120 degrees F (49 degrees C.), check the fine-pitch apertures for shape distortion (stainless steel has a very poor memory, once it expands, it doesn�t always contract back to the same position). Check for dings and dents. A good stencil cleaning pr
Electronics Forum | Thu Aug 13 14:10:01 EDT 2015 | markhoch
Hi Sam, I have a feeling that what you're trying to communicate is that your DPAK's are skewing off the pad during reflow. This is caused by a thermal "mismatch" where the solder paste on one side of the DPAK becomes molten before the other, then th
Electronics Forum | Wed Aug 04 22:35:32 EDT 1999 | ScottM
| What oven temperature should be used to reflow solder (Sn63Pb37) on a PC board (0.075" to 0.100" thickness) in 5 to 10 minutes? | D... is correct -- it's all dependent on your paste and your oven. Call your paste supplier (each one has a technica
