microperforated

Microperforated refers to surfaces or materials that incorporate a very large number of tiny holes, typically with diameters well below 1 millimeter. The term is commonly applied to microperforated panels (MPP), engineered acoustic absorbers composed of a solid or composite face sheet backed by an air cavity. The microstructure allows sound energy to be dissipated primarily by viscous and thermal losses within the holes.

Absorption mechanism and design parameters: The performance depends on hole diameter, perforation pattern, open area ratio, panel thickness, and the depth of the backing cavity. Smaller holes and lower open area generally shift absorption to higher frequencies; a back cavity creates a tuned absorber with peak absorption at a frequency determined by the cavity depth and panel properties.

Manufacturing and materials: Holes are produced by laser drilling, precision punching, or chemical etching, often on metal, wood, plastic, or composite faces. Hole diameters commonly range from tens of micrometers to around 0.8 millimeters, with open area ratios typically less than a few percent. The panels are installed with a back air cavity or behind decorative skins to achieve the intended acoustic effect.

Applications and aesthetics: Microperforated panels are used in architectural acoustics for wall and ceiling panels, in interior design to provide a clean, continuous surface, and in automotive or consumer products where acoustic transparency is desired without visible perforations.

Advantages and limitations: The main advantage is the ability to achieve acoustic absorption with minimal visual intrusion. They can be lightweight and thin. Limitations include sensitivity to dust clogging of holes, dependence on a back cavity, potential impact on mechanical strength, and the need for proper sealing to maintain acoustic performance.