Electronics Forum | Mon Jul 08 14:52:40 EDT 2013 | hegemon
The smaller ball "missing" from the lower left is from solder migrating down into the adjacent via. The solder mask may have been damaged or missing prior to mounting the BGA device. The larger balls at the top right are due to uneven heating during
Electronics Forum | Wed Jan 22 10:24:23 EST 2014 | cyber_wolf
No matter how good your process is, you will get solder on the gold fingers/lands unless they are protected. We have proven that solder will get on the gold fingers in the reflow oven. How that happens....we arent't 100% sure...there are a lot of the
Electronics Forum | Mon Sep 19 21:35:54 EDT 2016 | shriram
Appreciate your suggestion. NSMD pads are used for this design, the anomalies we found are 1. the trace running between pads has a lesser solder mask height compared the other area of the pads. 2. the NSMD pads doesnot have a trench close to pad e
Electronics Forum | Wed Jan 04 07:32:35 EST 2017 | pavel_murtishev
Good day, Having recieved new batch of PCBs with OSP surface finish, I have noticed that some polygons not covered by solder mask and solder paste become darker after second reflow cycle compared to PCBs not being sent to reflow. I wonder whether i
Electronics Forum | Mon Aug 10 12:58:04 EDT 2020 | SMTA-64386637
We have found Acrylic CC under QFNs is a failure mechanism in thermal cycling. The coating acts as a wedge and causes solder joint cracks. We do not coat QFNs. To enhance reliability we have the vias plugged with solder mask. This eliminates some
Electronics Forum | Thu Feb 12 07:58:54 EST 2015 | erezah
A-610E, 10.7.4 covers solder mask discoloration. > Use that for your disposition > > In a previous > thread, Boardhouse told us "Here are a couple of > things that can affect color. * Material color > is the major, * Matte green from Enthone wou
Electronics Forum | Tue Dec 05 21:11:35 EST 2000 | Dave F
The CDROM player in my personal computer just died and I replaced it with a more lively unit. Being an inveterate gearhead, of course I had to field strip the old CDROM player as soon as I pulled from my PC [and got the new one running]. There are
Electronics Forum | Thu Feb 07 20:53:51 EST 2002 | davef
Regardless of the technique used for the mounting pad shape or definition, isolation of the plated through hole [PTH] from the mounting pad is important. If the PTH is contained within the mounting pad, solder will wick down the PTH. The amount of
Electronics Forum | Mon Feb 12 09:51:51 EST 2007 | rgduval
From what I see, you have a couple of options... 1. Hand solder the secondary side LED's. This is only a good option if you're going to be at low-ish volumes. Higher volumes tend to necessitate more automation to reduce production costs. However
Electronics Forum | Tue Nov 03 20:00:47 EST 2009 | davef
Solder Mask Adhesion Pull Test Tape List IPC-TM-650 Test Method 2.4.28.1, Adhesion, Solder Resist (Mask), Tape Test Method, defines the procedure for determining the adhesion of solder resists (masks) used over melting metals, (such as solder plated
