Perforated Metals—Technical Aspects of Punching Technology

Metal perforation is an important modern process that is achieved through various methods, the most efficient and useful is press and punch perforation forming. To fulfill various requirements, manufacturers have access to a number of techniques that fall under the press and punch perforation umbrella. Below, we will describe three of them at length: wide press, sectional press and automatic nibbling machines. Other methods that we will not describe include: plate shearing, folding, welding, leveling, rounding and surface polishing.

Wide Press

The most common perforation technique is wide press perforation, popular because it is most cost-effective and efficient method available. In wide press, the entire width of the plate is punched with every strike of the die, and a punch row or rows work simultaneously as the plate traverses the machine.

Wide press is considered the best option for high volumes of metal because it is a rapid process that commonly produces stress faults. Its tooling cost is also high. A leveler is used to fix these faults or distortions. With it, stress errors are removed through flattening. Since leveling does not adhere to a standard procedure protocol, strategy depends on the location of the perforated and non-perforated areas.

Sectional Press

To work on a small section or area, many choose the sectional press method, which, while carrying a lower production rate, is less expensive than wide pressing. Section pressing is also used for thick plates, up to 20 mm, because it takes fewer punches. Section presses may be connected to CNC equipment that pre-programs patterns and perforation areas. This allows for well-made, tailored products.

Automatic Nibbling Machines

The final technique that this article will discuss at length is the automatic nibbling technique. Automatic nibbling machines share one major feature with sectional pressing, which is that they work only sectionally. This is where the similarities end. Automatic nibbling machines are automated, with tools that change out on their own. Also, they make economical perforations by nibbling the contours. If needed, they can also finish the outer plate of contours.

The other processes involved in manufacturing of metal plates are leveling, plate shearing, and folding, welding, surface polishing, and rounding. For shearing, a straight plate shearer is typically used, however, in some high-precision processing, lasers are used. For bending, a CNC machine is commonly used, which suits even complex profiles. For welding, either a metal inert gas (MIG) or a tungsten inert gas (TIG) is used.

To post process the surface of plate, grinding and brushing techniques are typically employed. Sometimes, for different applications, the plate is polished—either mechanically or with the use of electric methods—and then de-greased and blasted with beads and sand.