Electronics Forum | Wed Sep 19 21:08:28 EDT 2007 | wailiang81
Those others parts also happend printed not accurate, but there is no solder problem. Only the QFP area looks bad condition.
Electronics Forum | Wed Sep 19 21:04:57 EDT 2007 | wailiang81
Hi,davef, thanks for your concern. The condition was the pasted printed off with around 0.8~0.9mm from the land pattern. This will easy observe at QFP area. At fiducial, the stencil seens aligned accurately. Once solder bridge happend, its easy to
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 | Wed Sep 19 11:50:02 EDT 2007 | stepheniii
nevermind misread the post. But if the silkscreen is too thick, can you switch to another PCB manufacturer?
Electronics Forum | Wed Sep 19 21:10:16 EDT 2007 | wailiang81
Yupe, if condition keep worst, most probably will re-allocate the PCB manufacturer.
Electronics Forum | Wed Sep 19 21:13:24 EDT 2007 | wailiang81
By vision. Could you elaborate the meaning for "the advertised repeatability for your machine"?
Electronics Forum | Wed Sep 19 09:48:38 EDT 2007 | slthomas
In addition to what DaveF said, I'd like to know if there are other parts on this pcb, and if the paste for those parts was printed accurately or not.
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 | Tue Sep 18 19:32:49 EDT 2007 | davef
Welcome Jimmy Let's mince words to help focus on the issues. When you say "QFP area solder paste shifted," do you mean: * Paste printed on land pattern perfectly, but moves after printing. * Paste printed off the land pattern, even though the stenci
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
