³Ô¹Ïtv / ENGINEERING EXPLANATIONSolder Mask Expansion / geometry and scopeOpening W + 2eCopper WSeparate three boundariesCopper land: electrical geometryPermanent mask: exposed areaPaste aperture: printed depositA signed offset is per side, not atotal width change.Conceptual illustration. Not to scale; examples are not process settings or acceptance limits.