Electronics Forum | Sat Sep 26 14:07:09 EDT 2020 | davef
Print no paste on the tin-plated, [test???] pad. Experiment by putting Kapton tape over the stencil aperture for the tin platted pad. Re-assess your reflow profile, since the liquidus of the two plating materials will be different. Evaluate your pa
Electronics Forum | Wed Mar 17 17:11:10 EDT 2021 | emeto
I would recommend flux approach. I have placed tons of these packages. They have plenty of paste on the balls, and tend to short easy when you screen paste. Even if you get the print right, you would still see more voiding compared to using just flux
Electronics Forum | Tue Jun 09 07:35:23 EDT 1998 | Steve Gregory
Hi there Gary, Your solder ball problem is very similar the problem I experienced, but I was using a water soluble paste at the time. It started by inspectors telling me that they were seeing cold solder on some SIMM's that we had built regularly. W
Electronics Forum | Tue Nov 28 21:16:17 EST 2006 | davef
J Rose at EMPF says: The introduction of no-clean solder fluxes in electronics manufacturing has given rise to greater levels of solder balling simply because the opportunity to remove them in the wash process does not exist. They are typically cause
Electronics Forum | Thu Nov 30 17:31:41 EST 2000 | Larry C.Dyck
i am looking for info on lead free solder screen printing
Electronics Forum | Thu Nov 12 11:21:42 EST 2015 | davef
IPC J-STD-003. Solderability Tests for Printed Boards
Electronics Forum | Thu Feb 11 20:38:47 EST 2016 | davef
Try: * J-STD-003 “Solderability Tests for Printed Boards” * IPC-4555 OSP Finish Specification
Electronics Forum | Tue Sep 01 10:39:30 EDT 1998 | Mike
| | | We are experiencing shorting on a BGA. The part has a 1mm pitch with a 196 I/O count. The problem seems to pop up without warning & disappear in the same manner. | | | Our pad design is .020" diameter pads with .025" solder resist diameter.
Electronics Forum | Wed Feb 23 07:36:22 EST 2011 | scottp
We have a new site that is in the process of starting up and doesn't run much (1 tube every couple weeks). They recently called me about using expired paste. I told them to print a few scrap boards and run them through SPI to verify good print and
Electronics Forum | Wed Mar 24 23:12:48 EDT 2021 | grahamcooper22
0.66 area aspect ratio...so for example...if the device is 0.5mm pitch QFP, the pcb pad may be 12 thou wide..make the aperture 9 to 10 thou wide...and reduce it's length by 10 % overall compared to the pcb pad.... Depending on device pitch, select ap
