Electronics Forum | Wed Sep 19 13:38:43 EDT 2007 | russ
What is your alignment method for printing? Vision? Mechanical? What is the advertised repeatability for your machine? Russ
Electronics Forum | Wed Dec 06 08:29:50 EST 2006 | David
Hi Pavel, We regularly use over printing on a multitude of problem parts including fine pitch QFP's. In an Automotive Environment the only thing you can change without a mountain of paperwork is the stencil. best way to work out how much you can get
Electronics Forum | Sat Oct 07 16:31:56 EDT 2000 | Elfego
Tray the electroform stencil.
Electronics Forum | Tue Sep 18 12:10:39 EDT 2007 | wailiang81
Hi, good day to all. This is my 1st question post in this forum. Hope able to share some knowledge here. As we know QFP area like 0.4mm pitch was a very critical area to control especially those PCB using silkscreen printing process manufactured. Onc
Electronics Forum | Thu Sep 20 07:26:42 EDT 2007 | davef
Jimmy So, it sounds like your stencil and board are made to dissimilar versions. Choices are: * Buy new stencil to match the pads on the board * Tweek position of stencil to better match-up with the pads on board, ignoring the fiducials. You may be a
Electronics Forum | Fri Sep 21 10:31:44 EDT 2007 | russ
this would be meaniung that somewhere in your documantation it should have spec called "repeatability" what this means is that when the vision aligns the stencil/board, the board will always be within "x" amount of the njominal xy "T" position, some
Electronics Forum | Sun Apr 25 10:28:46 EDT 1999 | Joe Cameron
Hello all, Been doing some comparisons on joints made using the soldering iron versus reflowed solder paste (on a QFP package). The difference is quite significant: the joints made by the soldering iron are inconsistent and in many cases not filled
Electronics Forum | Sat Oct 07 11:14:39 EDT 2000 | Aaron
1. It is hard to tell, but your PCB vendor should test the PCB. 2. I think the important thing is the width of the apertures. You should have it laser-cut, and control the width no more than 90% of half pitch. Good luck.
Electronics Forum | Mon Oct 09 19:56:41 EDT 2000 | Dave F
CJ: Arturo and the others make good suggestions. Consider: IPC-7525 Stencil Design Guidelines
Electronics Forum | Thu Jun 07 03:54:16 EDT 2007 | testbloke
I currently have issues with "slivers" of solder on or behind QFP devices. This has only occured on PB Free boards (we currently produce PB and PB Free on same equipment). This is not tin slivers, this is a long thin sliver of solder measuring up to
