Electronics Forum | Wed Dec 22 10:09:53 EST 1999 | Wolfgang Busko
Hello Everybody, I�m afraid I�m not the only one who suffers from sudden inexplicable but certainly foreseeable loss of data on profiles, processes and all the rest concerning this field. To my astonishment it happens every year in late december tha
Electronics Forum | Fri Dec 17 16:23:22 EST 1999 | Mike Naddra
Hello Henry, Tombstoning is caused (In most cases) by a force imbalance on either side of the component. As the solder becomes liquidous the surface tension of the liquid will pull the component to the center of the liquidous area. To solve the probl
Electronics Forum | Sat Dec 11 12:15:21 EST 1999 | Steve Thomas
We have a pretty challenging board (2-up panel, 15"x20", 48 20mil pitch QFP 100's and 2 25mil QFP128) that gives us LOTS of lead bridging on the 20 mil parts. There is typically very poor wetting on these parts also, and some joints just flat aren't
Electronics Forum | Mon Dec 13 05:43:27 EST 1999 | Wolfgang Busko
Hi Steve, 20 mil pitch shouldn�t be that problem nowadays. In your case bridging and poor wetting seem to go hand in hand. For the poor wetting try to eliminate it by using different paste (higher activated) and work on your profile. Coplanarity also
Electronics Forum | Mon Dec 13 09:43:28 EST 1999 | Chris May
As Wolfang says about slightly bent legs, handling is of the essence. Are these devices decanted into another tray for your machine. It may be worthwhile doing a "movement" chart for these components. Do not explain why or when you are doing it beca
Electronics Forum | Thu Dec 09 18:21:20 EST 1999 | Boca
Mike, Russ is right, no 'normal' wave machine will solder PCB's with 1" long lead length. I have seen waves modified to clear up to 5/8" leads, but the deeper the wave the uglier things get. They get uglier in that a lot more dross is produced, con
Electronics Forum | Fri Dec 03 03:58:12 EST 1999 | Wolfgang Busko
Hi Charly, For batch ovens there is no discussion. For inline loading interval depends on the oven you use, the amount of heat the PCB takes out of the zone and the capability of the oven to get it back in. The approximate time for the PCB to stay i
Electronics Forum | Thu Nov 18 09:34:58 EST 1999 | Wolfgang Busko
Hi Will, it�s possible to use second reflow for second side components without glueing or use of different alloy solders. Although the first soldered joints become liquid during the second pass the parts will not fall off as long as their weight does
Electronics Forum | Wed Nov 03 10:30:27 EST 1999 | John Thorup
Hi Anthony I'm not sure I understand your question. Do you mean move to a better or more precise placement or to an error or bad position? I'm not aware of any calculation that can predict movement since it is based on so many factors like component
Electronics Forum | Wed Oct 20 16:05:47 EDT 1999 | Mark Charlton
I knew this would happen. Someone wants to rework a bad BGA artwork by cutting a trace and adding a wire under a 292p 1.27mm pitch PBGA. Has anyone done this before? What kind AND size wire do you use? How do you hold it in place during the replc
