Al,
We make stencils, and I was personally involved at AMTX when the electroformed process was developed. Some of this will sound like an ad, but everyone has been volunteering vendors and so look at this as a suggestion.
Electroforming is an additive process, nickel plated to a brass sheet or mandrel with resist bumps that prevent plating in the areas where the apertures are going to be. The lip or gasket formed around the aperture is the plated nickel building or climbing the side of the resist during the plating process. It can be dialed-in to very specfic thicknesses as was suggested above. However, cost and turnaround can be a problem because the resist has a tendency to fall off during plating and several attempts are needed to produce a quality product.
Electroplating nickel to a laser cut stencil can also be done to minimize the sidewall scoring that takes place during the cutting process. The nickel helps the paste release in smaller apertures. There are also, electroplating techniques used on screens to increase durability over polymer emulsions.
Nickel is soft, even the "XL" brand AMTX had before it was sold to a competitor of mine. Xerox sold it (AMTX), that should tell you something right there. Too small a market, too high a price, too limited a competitive edge. If anyone reading this is using nickel, be sure to use a nickel squeege blade, the stainless blades will chew-up the nickel eventually.
I would recommend a good chemetch-electropolished stencil first for apertures down to 8 mils wide in their smallest dimension. We do that stuff all the time at half the cost of laser or electroformed nickel and the customers are more than pleased to save the money. I recommend Hybrid Screen Technologies @ 800-219-9950 in Minneapolis for your stencils.
Good luck...Dan H.
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