Homebrew PCBs

>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