Alloy Composition
Metallic materials used in the manufacture of embossing dies require specific hardness and thermal properties to withstand repeated impact. The grade known as cuzn37 is a brass alloy containing approximately sixty three percent copper and thirty seven percent zinc. It is the standard material for CNC engraving and hand finishing in the packaging sector.
Because it lacks significant amounts of lead, the metal is safer for operators to machine while maintaining enough ductility to prevent cracking under the high pressure of a platen press.
Thermal Stability
Heat conductivity is a primary requirement for any metal used in hot foil stamping. Because cuzn37 transfers heat evenly across the die face, it ensures that the foil adhesive melts at a consistent rate. This prevents hot spots that might cause the foil to flake or cold spots that result in poor adhesion.
The alloy expands predictably when heated, allowing for precise registration even at high operating temperatures.
Tooling Durability
Resistance to wear is measured by the ability of the die to hold a sharp edge over thousands of impressions. A die made from cuzn37 maintains its fine detail longer than softer magnesium plates. It is chosen for medium to long production runs where the cost of brass is justified by the reduced need for tool replacement.
The material is also hard enough to resist the abrasive nature of some coated paperboards.
