Electronics Forum | Mon Jul 30 18:52:43 EDT 2001 | Brian W.
You did not provide the stencil thickness or your aspect ratio. If your aspect ratio (Aperture width/stencil thickness) is less than 1.5, the paste will not release correctly from the aperture, leaving paste in the aperture. For example, if your pa
Electronics Forum | Sun Jul 29 08:36:39 EDT 2001 | davef
You have provided very little information. Two similar possibilites come to mind: poor pad solderability protection and old boards. POOR SOLDERABILITY PROTECTION: Maybe the nickel plating under the gold is oxidized, contaminated, or otherwise very
Electronics Forum | Sun Jul 29 23:58:08 EDT 2001 | Frank
Hi Dave Thanks for your information. The problem that I found is paste not stick well on pads ( solder paste printing process). When the table move down (PCB saperate from stencil) some of paste stick on aperture instead pads. Solder paste : Delta
Electronics Forum | Mon Jul 30 21:12:32 EDT 2001 | davef
"Poor release" (paste hanging-up in the stencil holes) could have three main (or combination of) causes: 1 Equipment: Stencil is too thick. Specifically, a 6 thou stencil should be OK, providing you don�t violate the area and aspect ratios in the fi
Electronics Forum | Tue Jul 31 00:48:55 EDT 2001 | Frank
Sorry I forgot to provide enough information. Stencil thickness is 6 mil Aperture width is 10 mil Aspect ratio (aperture area / wall area) = 0.72 Solder paste mesh size, type 3 (-325 +500) With this aspect ratio we can printing without any probl
Electronics Forum | Mon Feb 09 16:55:28 EST 2009 | cuperpeter
Hi Sachin, thanks for your feedback. According to our supplier, surface plating is electrolytic gold over Nickel(not ENIG), but I think that is a still improper thickness for Au. (according to 3rd Working Draft from September 2008 of IPC 2221B "0.4
Electronics Forum | Mon Aug 16 18:09:33 EDT 2004 | Kris
ok I agree there has been a confusion with terminology When you say electrolytic soft gold with a minimum thickness of 5-8 of Au, is there a standard that you spec this from ?
Electronics Forum | Tue Dec 10 10:26:56 EST 2002 | davef
Questions are: * What is the current plating on the connector that is over the "plating of the leads is Nickel (99.9% purity)"? * What are the temperatures and durations at those temperatures that you read on these connector leads? * What solder allo
Electronics Forum | Mon Aug 16 20:32:10 EDT 2004 | davef
First, we didn't say "electrolytic soft gold with a minimum thickness of 5-8 of Au". We said, "'electrolytic soft gold' thickness 5 to 8uin". FOCUS. ;-) Second, we're unaware of an industry accepted specification that you can reference. IPC-2221
Electronics Forum | Wed Aug 11 18:36:03 EDT 2004 | davef
90 Knoop. Q2: Thickness is 4 to 10 u" for Au and 300 to 400 u" for nickel A2: This looks like a ENIG spec. Although, the Ni is quite heavy, 150 uin is sufficient for most applications. [IPC-4552 ENIG specification: * Gold thickness of 0.075 - 0.125
