Photoetched screens are more exact
These screens for medical applications, hydraulic-valve screens, fuel filters, laser-light filters, extruding screens, and particle separation and sizing, are are made with photoetching. This approach means that the openings don't shift or change as the screens work. They also lack the burrs that are associated with stamped screens. They can be made with straight or tapered holes, and hole sizes are as small as 0.003 inch. They are usually stainless steel, but can be other materials. Many sizes and custom shapes are available, but the standard screens have 60 or 90 degree patterns with a maximum guaranteed perforated area of 18 3 21 inches.