Product category:
Electronics Manufacturing, Tools and Instruments
News Release from: Tecan | Subject: Plimsoll line and lattice bridging stencils
Edited by the Engineeringtalk Editorial
Team on 24 October 2000
Can-on-board solder migration problems
solved
Tecan Components has solved a range of problems associated with automated soldering of RFI screening cans/fences onto PCBs with the introduction of the 'Plimsoll line and lattice bridging stencils'.
In a single blow, Weymouth based specialist Tecan Components has solved a range of problems associated with the automated soldering of RFI screening cans/fences onto PCBs - with the introduction of the 'Plimsoll line and lattice bridging stencils' Traditionally, PCB assemblers experience soldering consistency problems while simultaneously reflowing RFI cans and other surface-mount components
This article was originally published on Engineeringtalk on 12 Mar 2001 at 8.00am (UK)
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The solder migrates up the sides of the cans, crucially drawing it away from the solder tracks where it should ultimately reside, resulting in blow holes and poor joints.
Down-the-line, it is then necessary to embark on expensive re-work action to ensure a good joint with the necessary electromechanical integrity is achieved.
Because of these problems, some PCB assemblers will not put cans/fences through the reflow process at all, soldering them as a separate time-consuming off-line operation.
Overcoming all these problems, Tecan has developed a technique which introduces a linear break in the plating, all the way around the walls of the screening can, so that solder can only flow up the wall of the can to a set height, that defined by the 'Plimsoll line'.
Solder will not 'wick' higher than this and therefore remains where it should be - on the pad to ensure a good joint.
To further enhance this, the solder paste stencil itself has a 'lattice bridge' printed between sections of the track, effectively encouraging solder to flow into an even seam.
The two-part technique is exceptionally effective, producing highly repeatable and consistent seam joints, without subsequent rework or separate assembly operations.
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