Electronics Forum | Thu Apr 12 09:50:51 EDT 2007 | pjc
There have been many designs of apertures for 0402, round, home plate, inverted home plate and various reduction amounts for square or rectangular apertures. What works best for a given application depends on PCB design, solder land finish, stencil t
Electronics Forum | Thu Oct 30 22:29:58 EDT 2008 | davef
For most applications, a nice square [or rectangle] pad works just fine. Assemblers ship boat loads of boards with these every day. It's reasonable for tight decoupling capacitor requirement applications to use round or radiused pads for components
Electronics Forum | Mon Dec 20 04:14:06 EST 1999 | Wolfgang Busko
Oh yes, that�s the thing with the PCB houses, always doing such things with our precious data and or wishes of the ideal paddesign. Without any aperture reduction we would have enough troubles with the PCB�s we mostly get. Wolfgang
Electronics Forum | Wed Jan 16 20:06:09 EST 2002 | davef
No, not as such. Consider: * Using the IPC calculator [free at http://www.ipc.org]. It allows you to consider / assess the amount of solder when designing pads. * Reviewing IPC-7525 - Stencil Design Guidelines. It gives general aperture guidelines.
Electronics Forum | Wed Dec 15 09:18:00 EST 1999 | Chris May
Can people let me know what reductions are typical for stencils. This can obviously be affected by the technology of the board, but for chip caps and R's do you use 1:1 and only reduce for finer pitch stuff ? Your help would be appreciated. Regards
Electronics Forum | Fri Dec 24 04:22:11 EST 1999 | Keith Stone
When you get to fine pitch you might want to try reducing the aperture on the long dimension of the pad only. If you reduce the width of the pad you can get solder paste left in the stencil giving insufficient or unsoldered joints. Reducing the lengt
Electronics Forum | Fri Dec 17 18:31:29 EST 1999 | Calvin Wong
One thing we found out when we did new stencil is this, you reduce the stencil aperture by 10% is actually based on the Gerber. Please note also that the PCB supplier also makes the PCB according to the Gerber and there is a reduction on the pads as
Electronics Forum | Wed Dec 15 09:47:31 EST 1999 | Wolfgang Busko
Hi Chris, the same reduction as for fine pitch (10-15%)has decreased the amount of solderballs enormously. Sure, with adequate pad design and good printing equipment and processcontrol you can get the same results but it does no harm as long as you
Electronics Forum | Wed Dec 15 10:47:57 EST 1999 | Christopher Lampron
I agree with Wolfgang. We are currently reducing appertures by approx. 10% even on the chip components. This still gives us an adequate fillet volume and very greatly reduces the probability of solder balling/beading. We generally refer to the manufa
Electronics Forum | Wed Dec 15 15:55:05 EST 1999 | Mike Naddra
As a general guidline I would agree with a 10% aperature reduction on chip caps , resistors, and fine pitch provided correct land geometries. When soldering to HASL surface finishes. Three things you may want to consider ; the stencil thickness, the
