Electronics Forum | Mon Aug 16 04:34:54 EDT 1999 | Earl Moon
| | One of the DFM suggestions I've seen is to remove the solder mask web, i.e. the mask between pads on 20-mil QFP devices. The rational is that if the mask is thicker than the pad the mask can prevent the stencil from making intimate contact with
Electronics Forum | Mon Aug 16 04:47:04 EDT 1999 | Charles Stringer
| | | One of the DFM suggestions I've seen is to remove the solder mask web, i.e. the mask between pads on 20-mil QFP devices. The rational is that if the mask is thicker than the pad the mask can prevent the stencil from making intimate contact wit
Electronics Forum | Mon Aug 16 07:54:05 EDT 1999 | Peter Barton
| | | | One of the DFM suggestions I've seen is to remove the solder mask web, i.e. the mask between pads on 20-mil QFP devices. The rational is that if the mask is thicker than the pad the mask can prevent the stencil from making intimate contact w
Electronics Forum | Wed Aug 18 21:03:41 EDT 1999 | Dave F
| | | | | One of the DFM suggestions I've seen is to remove the solder mask web, i.e. the mask between pads on 20-mil QFP devices. The rational is that if the mask is thicker than the pad the mask can prevent the stencil from making intimate contact
Electronics Forum | Mon Aug 16 16:54:57 EDT 1999 | Scott Cook
| One of the DFM suggestions I've seen is to remove the solder mask web, i.e. the mask between pads on 20-mil QFP devices. The rational is that if the mask is thicker than the pad the mask can prevent the stencil from making intimate contact with th
Electronics Forum | Fri Aug 20 03:19:22 EDT 1999 | PeterB
| | | | | | One of the DFM suggestions I've seen is to remove the solder mask web, i.e. the mask between pads on 20-mil QFP devices. The rational is that if the mask is thicker than the pad the mask can prevent the stencil from making intimate conta
Electronics Forum | Thu Apr 29 10:24:15 EDT 2021 | oxygensmd
I have the same issue but with one customer only. All the other have smaller or more difficult QFPs with really low bridging issues - close to no-one. I think the PCB and PCB design also an issue - other customers are using 32/64/100/144 QFPs and we
Electronics Forum | Thu Mar 25 20:09:35 EDT 2021 | grahamcooper22
What is the QFP pitch ? What aperture dimensions have you chosen ? Is the stencil laser cut then polished ? Your AFTER stencil size looks promising...your BEFORE stencil aperture size looks disastrous...would surely give bridges.. Your pcb pad siz
Electronics Forum | Wed Mar 24 23:12:48 EDT 2021 | grahamcooper22
0.66 area aspect ratio...so for example...if the device is 0.5mm pitch QFP, the pcb pad may be 12 thou wide..make the aperture 9 to 10 thou wide...and reduce it's length by 10 % overall compared to the pcb pad.... Depending on device pitch, select ap
Electronics Forum | Thu Mar 25 23:23:00 EDT 2021 | llawrence
The QFP pitch is 0.5mm. Pad size is 1.475 x 0.3mm, and the new aperture size is 1.32 x 0.22mm. I'm not sure about whether or not it is lasered, but on the newly ordered stencil I selected the polishing option. Looks like the pad width is already 2/3
