Electronics Forum | Tue Nov 25 05:20:20 EST 2014 | grimus
Could be. I am making overprint to achieve proper amount of solder paste inside hole. Now I am trying to reduce maximum overprint and compensate it with step - up stencil. This could reduce effect that some particles of solder paste are not gathering
Electronics Forum | Wed Jul 23 05:47:53 EDT 2003 | iman
Yo Thanks! right on the money pad, the pinhole occurs mainly in the (fillet's) top-surface central of the whole solder (fillet surface) area. Like you said, large surface area, lowest surface tension. that's a possible cause, that the potential voi
Electronics Forum | Wed Dec 08 17:58:44 EST 1999 | Dave F
Dave: You should see a solder smudge on the gold plating where the ball was attached, if there is (was) solder reflow during either the (1) BGA fabrication, (2) your BGA attach, and / or (3) your BGA removal. You rework will not remove the solder
Electronics Forum | Tue Dec 28 15:35:21 EST 1999 | Mike Naddra
Edmund, An 0603 component should not fall from the board durring an inverted reflow pass, provided that: Your land geometries are correct for the package type (Start with SM 782 guidlines)- as surface tension of the liquidous solder is what holds
Electronics Forum | Sat Mar 21 12:19:51 EST 1998 | David Pick
I have read somewhere of a ratio of component weight vs. surace contact area rule for double reflow soldering. This ratio is the maximum weight vs. surface tension to hold a component on during the second reflow. With this number, a person could weig
Electronics Forum | Tue Sep 12 09:50:31 EDT 2006 | C.K.
There is a formula for that out there somewhere. It has to do with the part mass and the area of solderable surface. If the part mass is too great in relation to solderable surface area, the part falls off in a d/s reflow cycle. Anyone remember th
Electronics Forum | Tue Sep 12 22:03:22 EDT 2006 | davef
Really Rocky? What's the meaning of Russ' "if it will fit" in your scheme? As an alternative to your scheme, he could glue the nut on its side, tie a string through the hole in the nut, attach the other end of the string to the open door, and the
Electronics Forum | Thu Nov 02 03:42:49 EST 2000 | CHRIS MAY
Tombstoning primarily occurs due to the fact that the paste may melt and wet the metallized face of the chip earlier or better at one end than the other. This could be due to a difference in heat capacity (thermal shadowing ?) or that one end of your
Electronics Forum | Thu Jul 27 13:59:04 EDT 2000 | Chrys Shea
Sounds like the problem is design realted - here's a cheesy trick if your product/process permits: (you know how I love my cheesey tricks!) Put an adhesive dot between the pins that are bridging. If you're gluing bottomside SMT components to the bo
Electronics Forum | Thu Jul 20 14:02:31 EDT 2000 | Deon Nungaray
Hi Bob, I know that that conductive adhesives have been considered as a lead relacement in the past, but have been ruled out due to cost and other process issues (surface tension etc..) IBM has extensive development data on the topic and had come up
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