Electronics Forum | Wed Mar 02 05:14:07 EST 2005 | ABHI
Guys, Solder paste height worries all of us as we encounter the non wets after reflow. More so in fine pitch QFP's. The non wets are not always caused by solder paste height. Many other contributors. Even the pad geometry on te board can contribute t
Electronics Forum | Tue Feb 21 21:17:41 EST 2006 | Cal Kolokoy
M, The paste height is what you establish it as. You're probably using a laser measurement system, and these depend on where your reference datum is. Some will measure from a silkscreen, a trace, or solder mask. These add height, not to mention H
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 Apr 17 07:45:43 EDT 1998 | Robert Meston
We have to mount our SMD devices 0.1 to 0.4 mm off the pcb PCb substrate to compensate for thermal stressing in a Space enviroment. Has any one any ideas or contacts for dissolvable pads. this only applies to leadless components
Electronics Forum | Tue Jul 13 16:19:05 EDT 2004 | Inspection Solution
Hi Mark, There are many tools available for measuring solder paste height. Most machines use laser as the basis for inspection while others use structured white light. If simple height and width inspection is all that is required, you can look int
Electronics Forum | Tue Feb 22 08:40:12 EST 2005 | JB
A couple of features on your stencil printer that should help with a couple of potential printing processes: A temperature control unit and the automatic understencil cleaning with the chemical of your choice. That alone, will reduce the chances of
Electronics Forum | Wed Mar 30 08:06:17 EST 2005 | davef
Considerations are: * If the nonwetting is component lot specific, the could be solderability issues with that lot. * If the nonwetting is is a broader based component issue, the solderability protection on the component may require a different reflo
Electronics Forum | Wed Mar 30 15:15:03 EST 2005 | chunks
This is a pet peeve of mine. The paste height requirement is generally asked because the customer has no clue about screen printing, but knows to ask this question. If he did know even a little about printing, he�d ask you to assure the �volume� of
Electronics Forum | Thu Mar 31 07:56:31 EST 2005 | cn
I agree with chuck, but would like to add. 2D is a great option and helps to keep your printing process in check, it will measure the x & y coverage on the pad. It will help you determin when your stencil aps become clogged or when the bottom of your
Electronics Forum | Thu Oct 27 07:57:35 EDT 2005 | Bob R.
Nearly all of our assemblies have to meet class 3 requirements and we regularly use 5 and 6 mil stencils. If you've got reasonably well controlled processes you won't have any trouble getting class 3 joints on QFPs and discretes.