Electronics Forum | Mon Jun 25 20:37:14 EDT 2001 | davef
You are 100% correctamundo that the pad on PCB should be the same as the pad on the BGA interposer, but let�s not expend that thinking to the aperture of your solder paste stencil, right away. Generally, paste on large pitch BGA is often 1:1, but as
Electronics Forum | Thu Sep 15 21:25:43 EDT 2011 | darby
G'day folks - haven't been around for some time but still soldering on. Question for y'all. One of my design engineers has shown me a Creative PCI audio card with a TQFP48 attached. 0.4mm pitch. Let's say the pin width is 0.2mm and the pad design ha
Electronics Forum | Thu Sep 15 21:36:52 EDT 2011 | darby
I also posted this in the design section... G'day folks - haven't been around for some time but still soldering on. Question for y'all. One of my design engineers has shown me a Creative PCI audio card with a TQFP48 attached. 0.4mm pitch. Let's say
Electronics Forum | Wed Aug 07 17:20:17 EDT 2019 | orbitcoms
The aperture over the pads is set to 95% coverage of the pad. The stencil is 0.12 mm thick.
Electronics Forum | Wed Aug 07 18:32:22 EDT 2019 | orbitcoms
How would I measure/observe coplanarity issues ?
Electronics Forum | Wed Aug 07 01:41:27 EDT 2019 | orbitcoms
Hi I am having trouble getting solder bridges on TQFP-100 (0.5mm pitch) components. The boards are pasted on semi-auto printer using laser-cut 0.12mm stencil and SN63 NC257-2 T4 paste. The components are placed using Samsung CP40LV and tghen reflow
Electronics Forum | Wed Aug 07 12:41:58 EDT 2019 | slthomas
Are the apertures on the stencil reduced in width or 1:1 with the pads? It depends on the pad width and foil thickness but we usually reduce aperture width for any part that results in an aperture wall spacing of less than 8.5 mils.
Electronics Forum | Wed Aug 07 18:00:56 EDT 2019 | orbitcoms
I am doing another run today. I'll check how central the machine is placing the components onto the pads. I wonder if the part is off slightly and smudges past across the pins? What about if the part is being placed too deep into the paste?
Electronics Forum | Wed Aug 07 22:40:03 EDT 2019 | slthomas
Most placement machines will do a check for that prior to placement and reject the parts. I just wondered if that was something that you'd experienced while also seeing the bridges.
Electronics Forum | Thu Aug 08 22:22:05 EDT 2019 | sssamw
Did you solved this issue? I would recommend you track online station by station, until you detected the solder bridge, so you can narrow down the analysis scope and focus on potential causes.
