Electronics Forum | Thu Jul 07 18:16:36 EDT 2005 | russ
What size discrete components and have you evaluated your pad geometries? If pads are too far apart this will happen. The flux resudue is simply there because you didn't solder the component. It will stay on top of the solder bump. You can see this
Electronics Forum | Fri Sep 09 15:02:29 EDT 2005 | russ
What are the Mfg specs for pad layout? I had one that was wrong and we changed the center to center spacing to .032" and the width to .015" wider (.0075" on each side)than the solder terminations and everything was fine. As a general rule I never t
Electronics Forum | Mon Sep 19 09:02:10 EDT 2005 | clampron
Good Morning Everyone, We have a customer that produces RF based assemblies. We are building several board types for them, all of which have an "RF" area of the PCB. This RF area does not have any mask to define pads. There are also several issues w
Electronics Forum | Sun Sep 25 11:18:16 EDT 2005 | CS
Hi! I'm facing a strange problem where PCB expanded in X & Y-axis after bottom-side reflow. When the PCB send for Top-side printing process, it is abvious that the printing alignment on the PCB's pads are out. With the problem mentioned above, I am
Electronics Forum | Thu Mar 02 09:23:05 EST 2006 | Bob R.
I never understood the statement "process indicator". The 7095 committee used that wording but didn't explain it. Other than really unusual cases such as champagne voiding, BGA voids are not a reliability issue. A half dozen studies have come to t
Electronics Forum | Mon Sep 11 14:58:16 EDT 2006 | cuculi54986@yahoo.com
Steve, Let me guess, you were using this one: http://www.panasonic.com/industrial/components/pdf/abd0000ce10.pdf That part sucks. They have a newer part number that is supposedly "reflow-friendly". Unfortunately, I can't convince our quality de
Electronics Forum | Thu Apr 12 10:01:43 EDT 2007 | realchunks
Hi aj, Pete is right, there are several variables that can affect your quality when it comes to stencil design. A good idea is to have a stencil made with various designs incorporated into it. A lot of engineers like the reverse homeplate design.
Electronics Forum | Wed Jul 25 11:55:21 EDT 2007 | ck_the_flip
Zoinks!! Doing the homeplate design on 0402 will actually make your tombstones WORSE! Think about it. Your wetting forces are now on the ENDS of the device with no solder paste toward the middle of the device to tack the part down - a gauranteed f
Electronics Forum | Wed Feb 20 09:07:19 EST 2008 | scottp
I've done some pretty scary cross-sections of chip sized coils with AgPd terminations with Pb free solder. The AgPd went into solution and there was essentially nothing left to solder to. We also had convex fillet shapes that clearly didn't meet wo
Electronics Forum | Thu Feb 21 03:25:58 EST 2008 | jlawson
I have seen smt chip varistors with Pd/Ag teminations that had poor wetting in terms of good fillet in LF (sac305) soldering. We found that the solder tended to be attracted to the plating on the part and off the actual pad (silver Immersion). This c
