Electronics Forum | Mon Jul 29 18:59:08 EDT 2002 | davef
Stand-ups are a common problem with 0402. Search the fine SMTnet Archives to get started.
Electronics Forum | Wed Jul 31 17:35:16 EDT 2002 | davef
* Finally, when soldered by hand, do the problem pads take solder? Yes, the XRF analysis will be interesting.
Electronics Forum | Tue Jul 30 10:04:51 EDT 2002 | dason_c
Dave, I am very interesting to know about the dewetting or pull back, we are currently use the uP78 paste. Will nitrogen, profile setting help to reduce the dewetting. Thank.
Electronics Forum | Mon Jul 29 16:43:55 EDT 2002 | mcm4me
I have a customer with up to 8% scrap from one board supplier and 1% from another supplier for solder dewett and no wet over ENIG finish with mask defined pads. Initially I suspected mask residue on pads because of the no wets but I have come to find
Electronics Forum | Tue Jul 30 12:15:15 EDT 2002 | Rick Lathrop
Hi Dave, The paste applied to the board ends up on the tombstone. The pad has a thin covering of solder most of the time, this is why I think they call it a dewet. Occasionally the pad shows some areas of gold and very rarely are some pads not wet at
Electronics Forum | Thu Aug 01 08:58:47 EDT 2002 | Rick Lathrop
Good morning Dave F. I am not going to try to touchup the solder pad until I get surface analysis work done, don't want to ruin the evidence. I am getting XPS work done not XRF, XPS is X-ray Photoelectron Spectroscopy and can see very thin films of o
Electronics Forum | Tue Jul 30 17:47:50 EDT 2002 | davef
Dewetting: Solder does not adhere to lead or land, caused by: * Poor solderability of lands. * Poor solderability of leads. * Solder paste integrity. * Lead plating integrity. Need more information, please: * What is dewetting [ie, component, pad, e
Electronics Forum | Tue Jul 30 08:37:39 EDT 2002 | davef
When you talk about 'poor wetting', 'dewett', 'no wets', etc.; are you seeing solder pulling back or away from the pad? Please describe the condition. Dewetting. The condition in the solder joint in which the liquid solder has not adhered intimate
Electronics Forum | Tue Jul 30 17:51:18 EDT 2002 | davef
Comments are: * Peak at 245�C for 40 sec seems like a very long time. I�d expect the time at 245�C to be 10 to 15 sec. This long time at peak could dewett the pads. * Really, their 2D vision on the printer can verify solder presence? * A thin coat
Electronics Forum | Wed Jul 31 08:23:49 EDT 2002 | mcm4me
221C). 2D vision can very effectively detect % pad coverage, I use it on my DEK and this customer has an MPM which I also believe to be capable. Here is another fact, when the customer uses Brand X solder paste the defects due to what they call pad
