>With the cost of solder paste in prototype
>quantities somewhere between $25-40 per 250gm a more
>conservative approach is quite attractive.
So you believe this is the same thing board manufacturers use in bulk
hence more affordable to them? I doubt it.
--- In Homebrew_PCBs@yahoogroups.com, uhmgawa <uhmgawa@m...> wrote:
> Phil wrote:
> > I've often wondered why not use a cnc machine to cut a paste
stencil?
> > Bascially, its just a couple mil thick piece of plastic sheeting
that
> > you squeegee (sp?) the solder paste over. A stencil is pretty
easy to
> > use - I watched a guy prep a board for reflow in about 5 minutes
with one.
>
> Stencils are really a production assembly tool used
> where volumes of boards are being produced. The
> amount of solder paste waste/contamination otherwise
> is excessively high.
>
> For contemporary solder paste formulations, once the
> paste is brought to room temperature and handled in a
> stencil screening process the shelf life is drastically
> reduced. With the cost of solder paste in prototype
> quantities somewhere between $25-40 per 250gm a more
> conservative approach is quite attractive.
>
> --
> uhmgawa@m... www.gnu.org