Copper is a conductor of heat and electricity, is easily formable and can be perforated into a wide variety of patterns and punch outs. Since copper fares well in a variety of temperatures and can handle exposure to water without rusting, the number one application for perforated copper is in exterior building design.
They act as sun shades, decorative panels and building facades. Another common perforated copper product is decorative grills, often stamped with complex, non-repetitive patterns made of multiple shapes.
These are generally used in interior building design as room dividers, decorative fireplace screens and kitchen cabinet inserts that offer an alternative to glass. Radiator covers are often made of perforated copper, which conceals the radiator while still letting heat out.
Ceiling panels, screens, lamp shades, tubing, sound isolation sheets, stair treads, metal furniture, valves, door panels, kitchenware like baskets, pasta strainers and food covers and any decorative metal product that provides shade or ventilation are also commonly made of perforated copper. It also provides enhanced electrical performance as liners in connectors and heat shrink tubing.
Like all perforated metal, copper products are formed by a stamping press. Since most copper perforations are decorative, the press punches are of a complex and fancy design and therefore often require the aid of a CNC machine. CNC operated punch presses offer higher precision and accuracy but are less efficient.
The process begins with large rolls of copper sheet metal that are fed into the punching machines. The machinery moves the copper sheet around in both axes underneath a stationary punch. The pattern is then punctured into the sheet by using high amounts of force and weight.
Punching presses penetrate through the metal at anywhere from 50 to 400 strokes a minute, depending on the thickness of the copper sheets and the complexity of the pattern. Since copper is a malleable metal, manufacturers are able to produce a wide range of different patterns ranging from small, widely spaced shapes to screen-like patterns with large gauges and high transparency.
Most decorative perforated copper products are only polished on the side that will be visible. Antique finishes are also available for a higher cost.