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 | Mon Dec 16 10:05:29 EST 2002 | Grant Petty
Hi, Thanks for the info. We are reflowing the boards, but just barely. Sometimes we get the QFP in the middle of the copper area not reflowing, and it's pain. The joints are dry, and I am not sure if it's caused by lack of heat, or the flux going ba
Electronics Forum | Mon Jan 26 03:45:37 EST 2004 | Vinny
Hi All, We are producing a veriety of RF related PCBAs in which we see Unsolder/Mislaigned on a regular basis. In these baords usually one of the pad is connected to a signal trace and the other pad is connected to very huge ground plane. This gro
Electronics Forum | Thu Aug 28 08:43:56 EDT 2008 | rgduval
You wouldn't think that placement would affect dewetting or solderability....I wouldn't have either, until it was the only thing left in our process, and when we changed it, things got better. I couldn't begin to explain why, either. The only concl
Electronics Forum | Wed Jul 25 11:55:21 EDT 2007 | ck_the_flip
Zoinks!! Doing the homeplate design on 0402 will actually make your tombstones WORSE! Think about it. Your wetting forces are now on the ENDS of the device with no solder paste toward the middle of the device to tack the part down - a gauranteed f
Electronics Forum | Mon Aug 16 20:19:10 EDT 2004 | Grant
Hi, We have both Vapor Phase ASSCON semi auto as well as Soltec convection inline ovens. I must say we had no end of problems with Vapor Phase. We tried everything, and just could not totally eliminate tomb-stoning completely. We would always get a
Electronics Forum | Wed May 09 13:11:22 EDT 2001 | zam_bri
Hi.. Recently, I have received a few reels of 0402 with an old date code ( but still less than 2 years old).I don't have a capability in-house to carry out the solderability test except for the dipping test ( dip the components in the molten solder
Electronics Forum | Sun Jun 10 12:15:37 EDT 2001 | procon
Hello Danial, Leave it up to most to blame the relow oven for their tombstoning problems when in fact it is usually the last to cause it. The biggest culprit of tombstoning is the pad design followed by the print quality. Usually, we find that the p
Electronics Forum | Wed Oct 06 15:29:24 EDT 1999 | Tony
| Our first article inspection after machine placement can take several hours depending on the complexity of the board. The operator visually checks the board against the drawing and bill of material. I'd be interested to hear if there are any other
Electronics Forum | Fri Apr 16 11:07:53 EDT 1999 | Vic Lau
| | We process both tin/lead plated boards and gold plated boards in our surface mount group. I have used Sn62/Pb36/Ag2 solder paste on all gold plated boards to help prevent gold scavaging. To reduce the amount of different solder pastes we have t
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