Do not count copper twice in a stack budgetUse pressed or cured dimensions and one board-thickness measurement convention. Glass style alone does not define the pressed dielectric thickness.Do not count copper twice in a stack budgetConceptual cross-section; thicknesses and proportions are illustrativeOuter copper: separate contributionPressed prepreg: agreed intervalCore including its inner copperPressed prepreg: agreed intervalOuter copper: separate contributionCoatings: if included in measurementA core thickness may include its copper; confirm the convention before summing.³Ô¹Ïtv · Engineering explanation · Conceptual, not to scale