Electronics Forum | Thu Jul 21 09:43:10 EDT 2005 | davef
We agree with Russ. The solderballs are probably the result of printing too much paste on the board. In designing your 5 thou thick stencil: * Aperatures for the pads should be identical to a IPC-7351 - SO8 [or worst case http://www.vishay.com/docs
Electronics Forum | Tue Jan 27 08:08:51 EST 1998 | Jon Medernach
| I have the following questions with regards to the solder printing stencil design : | 1) Is the Electro-polish process recommended for laser cut stencil ? | 2) Should the aperture walls be slanted at an angle or straight wall, i.e. trapezoidal |
Electronics Forum | Fri Dec 08 11:30:19 EST 2006 | ganoi
We discussed about applying 2 dots of glue on either sides of the LED body, but have yet to try it out. Other discussions include conductive adhesive, using fixturing with weight, different stencil aperature design, hand soldering.
Electronics Forum | Wed Mar 24 11:09:44 EDT 2010 | rajeshwara
Hello Sir I faced the same problem for QFP in DTH product in India. IPC stated that void should not be more than 25% of solder joint. But this type of void definatly create problem during functional test. Please check the folloeing point... 1.Check t
Electronics Forum | Fri Dec 17 10:05:59 EST 1999 | Victor Salazar
You might want to check your paste application. We eliminated this problem with reduced aperatures, and homeplate designs on our stencil. The paste process is very important in eliminating solder balls. See Solder aperature guidlines in the forum.
Electronics Forum | Fri Dec 20 15:38:53 EST 2013 | island2013
Aperature layout on your stencil could be a root cause as well. Home plate design aperatures have cleared this issue up for me in the past. If it's a clean product, running through the wash may get rid of quite a few of them. Also check your IPC s
Electronics Forum | Mon Aug 31 22:30:09 EDT 1998 | Kelly Morris
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. The center
Electronics Forum | Tue Sep 01 19:16:51 EDT 1998 | Kallol Chakraborty
| 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. The ce
Electronics Forum | Tue Sep 01 02:50:40 EDT 1998 | karlin
| 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. The ce
Electronics Forum | Tue Jul 12 20:03:13 EDT 2005 | Tom
Most Lead Free Solder suppliers are saying that stencil aperatures should go to 1:1 or have no change from previous stencils design. Only one solder supplier seems to be complicating the process....is their solder very different?? Can anyone share st
