Elements that determine specifications are plate and holes.
Perforated metals are also called perforated wire meshes. Thus, they are regarded as a kind of wire meshes. It is possible to punch holes anywhere in a metal, so perforated metal is characterized by easy after-processing such as bending and mounting holes. Compared with metal lath used as mortar foundation and crimp wire netting having curled wires, perforated metal is excellent also in that the processing of metal surface is possible without concavity or convexity.
Elements that ultimately determine the specifications of a perforated metal are plate (particularly metal) and holes. Specifically, the combination of "material, plate thickness, plate shape and plate size" and "hole shape, hole size, hole-to-hole distance (pitch) and hole arrangement" can produce various perforated metals. In addition, such various perforated metals can be diversified further by post-punching processes, namely bending, surface treatment and its methods."
Three major types of arrangements
Typically, there are three types of perforated holes arrangements, namely 60˚ houndstooth, 45˚ houndstooth and parallel arrangement (90˚). They are distinguishable by connecting the centers of adjacent three holes. For example, in the case of 60˚ houndstooth, connecting the centers of adjacent three holes forms an equilateral triangle (right triangle), each angle of which is 60˚.
Similarly, in the case of 45˚ houndstooth, connecting the centers of adjacent three holes forms an isosceles triangle. It is the same arrangement as that of five-spot on dice. Some manufacturers call it "angle houndstooth." In the case of parallel arrangement (90˚), holes are literally arranged in a parallel fashion, and connecting the centers of adjacent four holes forms a square. It is the same arrangement as that of four-spot on dice. In the case of 60˚ houndstooth, the shapes of the first holes and the last holes are different. Because a punching pattern reflects the mold shape, it looks like asymmetrical houndstooth. When you want to make the shapes of the first and last holes the same, backfilling by one row to make the arrangement symmetrical is necessary.
There are also two punching types, namely normal houndstooth type and reverse houndstooth type. In the case of a normal houndstooth type, holes are staggered in parallel with the short sides of plate and the plate is fed along its long sides. In the case of a reverse houndstooth type, holes are staggered in parallel with the long sides of plate. Processing becomes difficult if the pitch is extremely narrow because of relation between plate thickness and holes. In such a case, a skipping type mold is prepared. The first holes and the last holes alternately protrude toward either side of the plate. Even after skipping type perforation, recovery to non-skipping pattern is possible by manually backfilling unnecessary holes.
Metal perforation is a kind of press work.
Metal perforation is a kind of press work where a metal plate is punched using metal mold. In common press work, those having been perforated become products. In metal punching, however, plates having been perforated become products. Therefore, various knowhow is required of metal punching manufacturers, such as mold technique for transferring a strain generated during processing toward punching equipment and methods for enhancing precision.
Punching press is basically a method of perforating a flat plate. To form a three-dimensional shape, post-punching fabrication is necessary. Press-molded products distributed as perforated metal products, products bended by sheet metal work, cylindrical products and curved products are subject to such secondary processing.
Punching work is basically done to flat, quadrangular materials. However, Uchinuki has the past records of the punching of three-dimensional extruded aluminum materials. The post-punching cutting of plate periphery makes it possible to also produce irregular-shaped products.