Electronics Forum | Mon Jul 16 14:38:22 EDT 2001 | ohboy
If your pad designs don't meet IPC recommendations, using home plate may have adversely affected the (possibly marginal) placement tolerances. This could also be caused by an incorrect home plate design, which IPC has also given recommendations for,
Electronics Forum | Mon May 07 16:07:05 EDT 2012 | davef
Start with targets based on the stencil thickness (for height) and stencil thickness times the aperture size (for volume). * Set reasonable upper and lower control limits (+ 25% and –25 % of the targets, for example). * Next, check the printer set-u
Electronics Forum | Fri Nov 19 22:18:03 EST 1999 | mark
Laser cut offers the following two major advantages... the aperture tolerance is much better and the trapezoidal apertures are more consistant. For the small difference in price, you get the assurance of
Electronics Forum | Tue Oct 04 06:52:28 EDT 2005 | Rob
Am I doing my maths right? 0.005 inches is 0.127mm which is crap for a stencil. Our supplier (laser cut)has an aperture tolerance of 0.005mm (approx. 0.000197 inches).
Electronics Forum | Mon Mar 20 21:46:31 EDT 2023 | emeto
The experimental way is the best approach for SPI settings and fine tuning. Have a start point of +/- 20%. You build 0402s and machine flags them 35% offset from value. You reflow, perform AOI - everything is fine. You go back and you move tolerance
Electronics Forum | Thu Nov 11 05:30:09 EST 1999 | Wolfgang Busko
For me it sounds like to much paste. If it worked in former runs with the same design and stencil look for changes in your printing process, check the volume and shape of your deposit. Redesigning pads and playing with aperture size allowing for mor
Electronics Forum | Wed Jan 08 08:20:52 EST 2014 | emeto
To most of our boards I give 20-30% tolerance in both directions. From experience if you have big aperture on your stencil, the squeegee will scoop certain amount of paste from this aperture and you will see lower height. Depending on your board supp
Electronics Forum | Fri Sep 21 14:03:45 EDT 2001 | jschake
I have observed solder balling for all aperture sizes tested. Solder balling levels appear to be better correlated against the amount of solder paste that is underneath the 0201 component terminations after placement rather than comparing this to th
Electronics Forum | Mon Sep 17 15:27:51 EDT 2001 | jschake
Challenges: The basic defects that impact assembly yield are bridging, satellite solder balls, and opens (i.e. tombstones / draw bridges). There are many variables with the stencil printing process that can impact these; several of them are listed
Electronics Forum | Mon Jun 07 07:31:59 EDT 1999 | tannlin
| Hi everybody, | | Somebody know the advantages of electroformed stencils on laser cut stencils ? | | any coment is apreciated. | | | thanks | | Al Al I have a quote for you from one of the major CEM's "anyone who thinks they are controllin
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