Electronics Forum | Thu Dec 16 15:00:20 EST 2004 | glaucon
Simple differences. Both processes require a very similar machine platform, controlled motion, vision fiducial recognition and alignment of a substrate (PCB or hybrid ceramic) to the "image", the image being either a stencil (hence stencil printing)
Electronics Forum | Thu Mar 05 11:53:09 EST 2009 | dcell_1t
Hello to all. for certain time, we have been struggling with some issues on a PCB where have tombstoning on 0402 components (due to pad design) and dewetting in qfp256 0.5 mil pitch (discussed on another threads on this forum) component, we have pro
Electronics Forum | Tue Mar 20 15:59:15 EDT 2007 | blnorman
We use preprinted labels and laser coding. For PCB we laser mark with CO2 (NdYAG for the aluminum heat spreaders). We either have an epoxy legend to burn out or we burn the solder mask to expose the copper ground plane underneath. Laser is a much
Electronics Forum | Thu Mar 08 02:04:50 EST 2007 | AR
I agree with John S., laser is definitely the way to go. More flexible and maintenance-free than applying printed labels. John S., are you using Yag or CO2? rgds AR
Electronics Forum | Tue Nov 09 17:12:38 EST 1999 | Dave F
Steve: Addressing your points: 1 FINE PITCH APERTURES Electropolishing Laser Cut Stencils: Laser cut should not requiring polishing. Geesh, how much money do you have for stencils? ;-) Oval Shaped Apertures: Pass. What do you expect to gain f
Electronics Forum | Wed May 10 01:00:09 EDT 2000 | gary
0.65mm pitch QFP. I believe that this is the borderline for Fine Pitch. Will I have a good paste release with Chem-etch matched with a rubber squeegee? I'm planning of a 15% reduction on the Width and no reduction on the length. Any feedback whether
Electronics Forum | Mon Nov 15 12:13:41 EST 1999 | Dave F
Steve: There are guidelines for determining if your aperture has the correct proportions to the foil thickness. Maybe that�s what you�re looking for: 1 Aspect ratio = aperture width/foil thickness Chemically etched SB GT 1.5 Laser cut SB GT 1.2
Electronics Forum | Tue Feb 04 08:32:49 EST 2003 | roertner
In my experience AOI's are good for checking machine setup I.E. first piece inspection. After that the only things they will typically catch are wrong parts, reversed parts, missing parts, and tombstones. I would however suggest getting an AOI with a
Electronics Forum | Wed Mar 07 12:57:15 EST 2007 | John S.
Hover Davis makes a feeder that can be fitted to many pick and place machines. Runs about 7k. I've seen print on demand feeders at tradeshows for about 30k. If you've got enough volume, you could also laser etch. There's more capital involved, bu
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
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