Electronics Forum | Wed Dec 27 23:04:10 EST 2006 | i want to learn from u
Most of pcb have white/black printing at bottom side of them to indicate the chip location. Normally, this printing are the same location to the place that glue will be mount. My problem are the glue size between the point that have printing and not
Electronics Forum | Fri Mar 02 00:21:38 EST 2007 | AMS
Hello, I havea 0.4mm pitch TQFP with heat transfer pad on the bottom side of component. I will appreciate any suggestions with regards to: 1) stencil thickness (Rest of components on board are 0603 passives and few 40 mil pitch IC's) 2) Stencil
Electronics Forum | Mon Nov 05 02:51:48 EST 2007 | omidjuve
our boards have many smd pads that has vias under them so when the screen printer wants to print the solder paste on it , it will penetrate through the via to the bottom side of the board and cause many problem for us . i want to know that is it sta
Electronics Forum | Tue Jun 17 09:24:43 EDT 2008 | rgduval
Could it be from a dirty stencil, rather than from the pick and place operation? We've seen a number of occurences recently with solder balls near some of our fine pitch components...we eventually diagnosed as dirty stencils...excess solder on the b
Electronics Forum | Tue Feb 03 10:10:27 EST 2009 | milroy
Hi, There is one thing missing still, you must put a TC from the bottom side of the BGA by making a hold on the test board at the TC can measure the temperature at exactly the middle of the BGA. You should be able to the dual time and peak temperatu
Electronics Forum | Mon Mar 02 10:23:46 EST 2009 | wrongway
You may need a glue despinser if you populate bottom side then wave. maybe a board deatacker at front of the line how about a multifunction pick and place machine so you can process all parts out there. we cleaned our stencils for years then we got a
Electronics Forum | Fri Aug 28 06:39:29 EDT 2009 | sachu_70
I had seen such effect caused by the wave itself, where the exposed wave surface was coated by a thin dull oxide layer which then adhered to the bottom side of PCB during wave soldering. You could verify if the wave surface is clean metal when the P
Electronics Forum | Fri Sep 04 07:26:23 EDT 2009 | Sean
Dear Davef, Thanks for sharing with me..I observed this creeping corrosion tend to appear on PCB via hole rather than other PCB location. Why this problem did not appear on PCB traces? Besides, I also notice that this problem only appear on the PC
Electronics Forum | Fri Sep 04 15:33:09 EDT 2009 | martinphill
Is it possible to Process Top & Bottom side PCBA simultaneously in One SMT Line. (An atrticle by Jagadeesh Rajagopalan, SMT Process consultant). Pls check this and suggest me whether it is possible? & What should be the Lead free Reflow Profile? ht
Electronics Forum | Sat Nov 21 01:42:28 EST 2009 | Sean
Hi Patric, You are right...WE found that this problem disappear once we seal the PCBA bottom side (Intel's Northbridge area). Once we remove the seal, the problem is coming back.. In this case, I thnk conformal coating is necessary... Besides, I
winsouce.jpg)