What’s the difference between perforated metal and expanded metal?

Perforated metal is manufactured by punching holes into solid sheet material, creating smooth, uniform openings with precise dimensions. Expanded metal is produced by simultaneously slitting and stretching a sheet to form raised diamond-shaped openings without removing material. Perforated metal is often selected where appearance, precise open area or acoustic performance are important, while expanded metal is commonly used where strength, rigidity and slip resistance are priorities.