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 | 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 | 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 | Fri Mar 16 13:47:56 EDT 2007 | ck_the_flip
Another thing to look out for... Flex circuits, if not fixtured properly tend to move around and, well, "flex" during screen printing. At another place I worked, we fixtured the flex circuit on a SMT pallet on the corner tooling pins to "stretch"
Electronics Forum | Fri Mar 16 23:38:36 EDT 2007 | mika
I don't understand so please explain in more detail. You say ~0.3mm shifted. In what direction is the paste shifted? is it shifted the very same directions on all panels? Only on this product or even with regular pcb:s? What is the size of the panel
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 Mar 14 20:06:54 EDT 2007 | vshan
Hi All i need some help here, currently experiencing connector leg shifted due to solder paste shifted from pad ~0.3mm. I did adjusted the reverse/forward X, Y and titah but still shifted. Product : flex circuit with 28 connector on the panel. Each
Electronics Forum | Thu Mar 15 09:28:19 EDT 2007 | jseagle
I have seen this when the fiducials are not spaced far enough in the X and Y.
