In the arena of metals and fabrication, appearance can be almost everything. Perforating in certain respects, is sort of of an art. It has been manufactured using perforating presses for well over a century. As times change, metal perforating evolves as well. Some of the principles behind perforating remain constant, will have and always will, although some have progressed in keeping with advances in metallurgy and overall technology. Thanks to cnc programming and cad, non-traditional patterns have become available opening the doors for unlimited possibilities including perforated logos and perforated images that resemble anything you can imagine. Overall, the perforated patterns have changed, the caliber of metals and alloys have improved, as well as the process of perforating metal is becoming much more efficient. But lets discuss the perforating patterns specifically.
Every perforated pattern obviously begins with the shape with the hole. A few examples of hole shapes are circular, elliptical, oblong, oval, square, rectangular, hexagonal, octagonal, clover leaf, and triangular. Custom hole shapes are offered also by designing a custom perforating tool. Each hole shape brings its aesthetic characteristics. The layout of the holes can affect the strength of the perforated material. As an example, holes may be perforated inside a straight pattern with each hole in perfect line both horizontally and vertically on the metal sheet. Rows of holes can also be staggered which is common practice to keep up strength in the finished product. The straight and staggered patterns create two entirely different appearances. In relation to strength however, a round hole perfed right into a staggered pattern creates the best overall strength versus open area. Round holes may be perfed more efficiently and economically than some other hole shape as the dies and punches required to punch a round hole would be the easiest and least costly to make. Round hole tooling will even last longer and it is easier to maintain. A round hole and staggered pattern is easily the most commonly commercially perforated pattern just for these reasons.
The outlet pattern actually has a direction on a standard produced in higher quantities expanded metal sheet. Prize a perforated sheet with a staggered pattern and you'll see that the stagger is usually on the short dimension from the sheet and also the straight rows of holes will run parallel to the longer dimension. For hole size, the main one to one rule should be considered. As a rule of thumb, when perforating mild steel and aluminum, the hole diameter must be at least the thickness from the raw material for reliable tool performance. In the case of stainless steel specifically, metal thickness needs to be at least one gauge thinner compared to the hole width for safer and much more reliable production. Concerning the punched patterns in metals another consideration is bar width, or the space between your holes. Just like the hole diameter, a 1 to one ratio of space between holes is absolutely the minimum easily of production increasing width the width with the spacing. Open area is a term used to spell it out the percentage of metal with holes versus the solid, un-perforated metal. The open area of the sheet will dictate many properties with the finished product including its appearance, needless to say, as well as its weight, its strength, being able to absorb heat, its sound absorbing capabilities, and how it can pass fluids.
Perforated patterns are carefully selected both for their aesthetic appearance as well as their real world performance being a finished product. The mixture of hole sizes, hole shapes, and a variety of perforating techniques create a nearly endless selection of perforated patterns to select from.