Electronics Forum | Fri Jan 19 06:52:36 EST 2001 | pteerink
We have had the same problem with several boards, and the problem was with the land pattern design on the PCB, not the stencil. We found that the part tends to center itself on the one large pad, and if the two smaller pads are not the right distance
Electronics Forum | Wed Aug 24 11:48:37 EDT 2005 | Anthony
Hello, we are currently designing our first PCB with surface mount components on both sides of the board. I understand about solder thieves in order to help short circuits. Are there any good white papers or books which identify the best practices w
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 Apr 24 02:56:12 EDT 2007 | chrispy1963
If the PCB you are using is a HASL pad finish and is a leaded assembly, we use homeplate pads with a 5 mil stencil. If the circuit has Enig finish and is PB-Free then we use 1:1 apertures with a 5 mil stencil Either method should provide no solde
Electronics Forum | Mon Apr 09 13:53:45 EDT 2018 | dleeper
I've never placed one of these before, but it looks like a poorly designed part. It has pads scattered asymmetrically around the body of the part. when it reflows this is going to apply uneven forces to the component, causing it to skew. I guess hav
Electronics Forum | Wed Feb 22 08:02:56 EST 2006 | dj44
I was looking for an stencil design for a 0.5mm pitch uBGA. Pad size is 0.38mm in diameter. We have been using 5mil stencil with type 3 no clean paste. What size aperture should we be using? Any suggestions?
Electronics Forum | Wed Oct 31 11:01:02 EST 2001 | dougie
Hi Dave, Thanks for the suggestions. To clarify a couple of the points... - What do you qualify as "small" & "large" parts? - Do not make the pad narrower than the lead width. The nominal or the maximum? If I use the maximum width I'll be back to s
Electronics Forum | Wed May 22 12:32:49 EDT 2002 | pwrgroup
which stencil vendor can deliver aspect ratio and area ratio and the statistical information to the user?It's difficult if the pad is modified.
Electronics Forum | Wed Feb 05 21:24:35 EST 2003 | davef
Stephen's correct. Radiased outer corners on 0402 pads really do seem to improve things. We aim to try "squared-up semicircles".
Electronics Forum | Mon Jun 28 08:25:54 EDT 2004 | Scott Dodge
What is the difference between a smooth finish organic coated bare copper board for fine-pitch components and HASL finish?
