Electronics Forum | Mon Aug 23 03:12:57 EDT 2010 | grahamcooper22
Possible route causes of bridging on fine pitch ICs are; too much paste (stencil aperture wrong), poor print quality (paste smudges during printing), pcb pads not flat depending on the solderable coating, paste has poor cold slump properties, too muc
Electronics Forum | Mon Jul 30 18:52:43 EDT 2001 | Brian W.
You did not provide the stencil thickness or your aspect ratio. If your aspect ratio (Aperture width/stencil thickness) is less than 1.5, the paste will not release correctly from the aperture, leaving paste in the aperture. For example, if your pa
Electronics Forum | Mon Aug 30 02:41:22 EDT 1999 | Dreamsniper
Planning to evaluate the above process... Can anyone can give me some tips/infos on the above.... e.g. stencil aperture design, aperture ratio, common problems and solutions they encountered on the above process, is the profile different from an ordi
Electronics Forum | Mon Mar 06 16:42:25 EST 2000 | Jon Wentz
Hi PR, FYI,some adhesives harden within the stencil apertures with IPA if not cleaned well. We used Heraeus PD955PY and had to closely inspect our cleaning process of the stencil. Just another tip, ask your adhesive vendor for their recommendation o
Electronics Forum | Mon Mar 06 16:42:25 EST 2000 | Jon Wentz
Hi PR, FYI,some adhesives harden within the stencil apertures with IPA if not cleaned well. We used Heraeus PD955PY and had to closely inspect our cleaning process of the stencil. Just another tip, ask your adhesive vendor for their recommendation o
Electronics Forum | Fri Mar 02 00:21:38 EST 2007 | AMS
Hello, I havea 0.4mm pitch TQFP with heat transfer pad on the bottom side of component. I will appreciate any suggestions with regards to: 1) stencil thickness (Rest of components on board are 0603 passives and few 40 mil pitch IC's) 2) Stencil
Electronics Forum | Thu May 03 01:07:18 EDT 2007 | pavel_murtishev
Good morning, Worth system for 0.5mm or more pitch paste printing. For less pitch (uBGA, 0.4mm etc) framed stencil are preferred due to better tensioning. Main issue with them is handling. Stencil apertures that are used for tensioning might be easi
Electronics Forum | Tue Sep 21 04:00:27 EDT 1999 | Wolfgang Busko
| My stencil thickness is 6 mil and we got qfp's with fine pitch. | how many percent should i reduce my stencil aperture using a 6 mil stencil for 0.5 mm pitch and 0.4 mm pitch ? | | thanks | We use 6 mil lasercut stencils with 15% reduction and th
Electronics Forum | Mon Nov 25 12:16:53 EST 2019 | slthomas
A reticle on a good microscope will measure individual apertures and aperture spacing fairly well if you just want to check a few. It's not fast, though. The other end of the spectrum would be a stencil measurement system that uses your paste files
Electronics Forum | Tue Sep 21 11:28:26 EDT 1999 | Dave F
| I've had some trouble pasting a test board for a MicroBGA trial. Most of the paste remains in the stencil apertures. | The stencil is 6 mil thick, laser cut and electo-polished. | The apertures are 12 mil in diameter with 20 mil pitch. | We are usi
