Electronics Forum | Wed Apr 17 02:30:03 EDT 2002 | seje
Hello. There is been a lot of talk about thick plastic stencils vs. metal stencils for adhesive printing, but how about thin plastic stencils? We used to use a very thin plastic stencil (from loctite) with printgap (=snap-off) to adhesive printing
Electronics Forum | Fri Apr 20 11:05:23 EDT 2001 | gcs
Just a bullet! My results are, .005" stencil thickness should measure between .0055" - .006" if your pressure is correct, metal blades and snap-off is set up correctly. Do you have aperture reductions at the QFP locations "typicial industry standard
Electronics Forum | Thu Jan 05 10:56:49 EST 2012 | davef
The high thermal mass of metal core boards makes them difficult to heat with hot air convection heating or IR. So, edge heaters are used for effective heating of heavy core circuit boards. Hakko and VJ Electronix offer edge heaters. We imagine othe
Electronics Forum | Fri Apr 20 16:05:17 EDT 2001 | gcs
We always reduce side to side, EXAMPLE: 12 mil width reduced to .010". Do you guys check viscosity ? Also maybe your guys are appling to much pressure on the sqweegee blades.
Electronics Forum | Tue Jan 03 11:30:13 EST 2012 | ppcbs
Try using Chip Quik to reduce the heat required for component removal. Along with your bottom pre-heater, use a temperature controlled hot air system to help heat up top side for component installation. http://www.pcb-repair.com/products.htm
Electronics Forum | Fri Apr 20 08:41:56 EDT 2001 | jimlew
For those of you out there, like myself who are still using 2-d to measure paste ht, I have 2 questions. 1. Typically, what tolerance are you applying to your ht? +- 1 mil, or what? 2. Are you using metal squeegees, and if so, have you found that squ
Electronics Forum | Fri Apr 20 15:27:00 EDT 2001 | jimlew
We do some aperture reductions - but it's not the 10% i'm accustomed to. Looks like it should be more than we currently do (I think we do 10% of length, but no width). Don't think we have a slumping problem, and we're not doing snap-off, only contact
Electronics Forum | Thu Sep 25 17:35:28 EDT 2003 | denis
To be precise, the component is a Xilinx Virtex platform FPGA with 1152 balls. We also assemble some DSPs up to 1000 balls with metal cover. At best, we can remove the components but it is almost impossible to find a working solder profile using IR.
Electronics Forum | Thu Nov 11 10:55:32 EST 1999 | KenF
Hi, could anyone tell me the maximum size of an SMD ceramic capacitor that can be assembled on a copper based substrate reliably? The SMD will be reflowed on the copper substrate. The main concern is the CTE mismatch between the ceramic capacitor and
Electronics Forum | Thu Sep 25 18:31:24 EDT 2003 | davef
Denis: You could be correct about metal reflecting IR. When we use our old IR station, we place pieces of aluminum foil around the component to be removed to protect the near-by components.
