Tenting the vias could inpact testability and reduces the ability to clean.
The safest solution is to use a batch cleaner with Kyzen or Envirogold 316 flux cleaner 5% with Di water. These saponifers reduce the surface tension of water and are excellent cleaners. The boards must be cleaned in the aqueous cleaner within ten minutes to remove the caustic soap. Kyzen in Manchester NH makes this cleaner and sells the Kyzen saponifier. The use of the batch cleaner allows you to use the existing aqueous cleaner and not contaminate the cleaner with saponifers that cloud the glass windows and require down time to descale the heaters of the tank with the saponifier.
John Goulet
Sr Manufacturing Engineer
-------------- Original message --------------
From: "weiner, mickey" <[log in to unmask]>
> Bogert
> What is the final finish of this board
>
>
> Mickey
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of - bogert
> Sent: Thursday, November 27, 2008 5:05 PM
> To: [log in to unmask]
> Subject: [TN] Tenting of vias and spare PTH
>
> We have an existing design PWA with socket mounted parts. The design
> has vias under the sockets as well as PTH under the sockets that were
> intended for use as spares to facilitate future design changes. The
> sockets are of the open construction frame type (an H configuration), or
> otherwise are body-less sockets. We are considering removing all
> sockets and direct soldering the components into the existing PTH using
> ORL0 type flux.
>
> We are concerned about flux residue and other forms of contamination
> such as from the PWB manufacturing process and the PWA assembly process
> getting into the open via and spare PTH and not being removed by the
> in-line cleaning system.
>
> We are considering having the vias and spare PTH tented in some fashion.
> We need to retain use of the tented spare PTH for future use if needed.
> What method do folks recommend to tent vias on equipment that was
> already designed with un-tented vias and spare PTH?
>
> On a go forward basis, we are considering mandating that if vias are
> used under components, they must be tented and we will not allow spare
> PTH under any component. Allowing spare PTH under open frome or
> bodyless sockets was a dumb idea.
>
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