Electronics Forum | Tue May 19 12:29:59 EDT 1998 | Richard Jackson
| Richard, | You may be encountering solder paste contamination | on the assembly during the printing process. Solder | will reflow on tin/lead plated lands therefore invisible. | If you are washing the assembly prior to inspection | then you are
Electronics Forum | Wed Aug 15 13:40:55 EDT 2001 | rkevin
Just as there are a number of causes of solder balling there are also several factors which can lead to or encourage the formation of solder beads. - During the placement of the component solder paste may be squeezed out from underneath the compone
Electronics Forum | Wed Sep 19 15:32:24 EDT 2001 | jschake
I�ll volunteer to answer this one for Jake. In order to prove the performance and capability of the stencil printing process, I think this level of inspection detail is required. However, in a production scenario where a known printing performance
Electronics Forum | Tue Sep 18 16:48:55 EDT 2001 | jschake
Why do you think that assembling the BGA, QFP, and fine pitch parts will solve your bridging problem? I would think doing this may cause you more grief by having these more massive components being reflowed upside down fall off during the second pas
Electronics Forum | Wed Sep 19 14:23:31 EDT 2001 | jschake
Pad Metallurgy Used: Copper OSP pads were used for all of the results that I have been reporting. The same design test boards with Nickel/Gold pads are available and awaiting further assembly tests. I will consult with a board technology and metall
Electronics Forum | Tue Nov 20 20:56:23 EST 2001 | davef
You�re correct. The release characteristics of epoxy differ from solder paste. Consider: * Using print/flood stroke, on-contact print cycle. * Printing slow enough to fill the hole with adhesive. * Overcoming the thixotropic [The viscosity of thixo
Electronics Forum | Mon Nov 26 14:49:20 EST 2001 | mparker
1. The formula for cubic area (LxWxH) applies to get the expected volume target value. Caution- do not assume the pad surface square are is correct for the part. Do consider the footprint of the device beign placed and its solder requirements to cre
Electronics Forum | Wed Mar 27 07:41:54 EST 2002 | paul_stamper
As Mitchell stated before, the cleaning of the stencil is rather important. When considering stenciling of adhesive you must review your stencil cleaning process. The recomended process is a ultrasonic cleaner with a heater option. These systems are
Electronics Forum | Wed Mar 27 19:26:53 EST 2002 | ianchan
After a whole night's self review, I think we can term the slant/tilt as "floating 0805, yet end-terminals have acceptable solder joint formation". the width portion of the 0805 RES/CAP is (floating)elevated from the PCB pad, yet both (width) termin
Electronics Forum | Tue Apr 30 07:49:38 EDT 2002 | johnw
shawn, define what you mean by solder ball's scattered across the board? I'd tend to agree with the thoughts of too much paste on chip's but normally your ball's would be mainly around these devices although som can move around depending on the surf
