Electronics Forum | Tue Jun 17 08:52:39 EDT 2003 | russ
Aspect ratio = width of aperture divided by height. E.G. 6 mil stencil at 9 mil wide = aspect ratio of 1.5. Value should be 1.5 min. Area ratio - use when length and width of pad are roughly same dimension like for BGAs and 0805 and smaller R-nets
Electronics Forum | Fri Dec 11 16:06:18 EST 1998 | Michael Allen
G, You'll find at least one old thread in this Forum on dual-reflow if you do a search. I found one dated April 7, '98 (searched on "reflow"); this particular thread includes a discussion about the maximum weight-to-surface_area for successful dual
Electronics Forum | Thu Jun 02 14:57:36 EDT 2011 | davef
We don't expect properly soldered first-side DPAKs to fall from the board during second-side reflow. The ratio of weight to solder surface area for a DPAK is 1.32 gm per in^2, which is well within the limit of 44 gm per in^2. [Search the fine SMTnet
Electronics Forum | Mon Oct 04 11:23:55 EDT 1999 | Mark D.
Does anyone have a list of component types that can be put on the bottomside of a doublesided reflow board that will not fall off during the second pass (Or on the otherhand, a list of components that will fall off)? This would be a list of parts tha
Electronics Forum | Mon Oct 04 11:28:46 EDT 1999 | Mark D.
Does anyone have a list of component types that can be put on the bottomside of a doublesided reflow board that will not fall off during the second pass (Or on the otherhand, a list of components that will fall off)? This would be a list of parts tha
Electronics Forum | Tue Sep 16 16:30:50 EDT 2008 | rayjr1491
Do you have any suggestions on what the area ratio should be for all PADS?
Electronics Forum | Tue Mar 24 17:08:52 EST 1998 | Steve Gregory
David, There was a thread going on the IPC TechNet about exactly the same thing... The ratio that was posted is: Less than, or equal to 30-grams per square inch Which means if you weighed a part and it is 30-grams, you'll need .033" of surf
Electronics Forum | Wed Nov 27 20:29:26 EST 2019 | sssamw
OK, if has concern on void in the function pin area, you need cross section of the pins solder joints, to see how much area ratio of the void to solder joint area. Of course you need make sure solder joint (the toe and heel, height)meet IPC requireme
Electronics Forum | Wed May 22 12:32:49 EDT 2002 | pwrgroup
which stencil vendor can deliver aspect ratio and area ratio and the statistical information to the user?It's difficult if the pad is modified.
Electronics Forum | Tue Apr 07 05:41:34 EDT 1998 | Bob Willis
Based on work I have been doing recently the most common reasons for component loss is board flexture and vibration on the reflow process. If parts do not reflow then weight is not an issue. There is a video on double sided reflow and PIHR from the S
