In the automobile and commercial vehicle industry, perforated sheets are already a proven construction and design element with a wide range of functions. They take on very different forms, have to be installed in complicated environments and perform their service there for many years. Examples include protective and ventilation grilles on engines, perforated body parts to optimize the weight of off-road vehicles and construction machinery, loading areas of transporters and tow trucks or engine housings on tractors.
The perforated sheet is not complicated in itself; it is sheet metal with punched out openings. In detail, however, precision and solutions adapted to the area of application are required in order to bring the advantages - including functionality, longevity, stability and lightness - of perforated sheets to bear in practice.
Locations
Perforated sheets from Schäfer are used in particular in commercial vehicles, such as construction and agricultural machinery, which have to function in corrosive conditions with exposure to chemicals, moisture, dirt and mechanical influences. A prominent example is the Grenadier off-road vehicle from INEOS Automotive, which is manufactured in the former Mercedes-Benz factory in Hambach.
Bionics in perforated sheet metal
Each hole type has specific areas of application and offers individual advantages. A diamond-shaped perforation allows a free cross section of almost 75 percent. In other words: A square meter of perforated sheet metal consists of 25 percent metal, 75 percent is open space, which explains the enormous weight reduction.
With the hexagonal perforation Hv 6.0–6.7, the free cross section and, similarly, the weight reduction can be increased to over 80 percent. This optimizes the air flow, increases rigidity and provides protection against mechanical influences caused by objects with a diameter larger than 6 mm.
“Originally, a diamond-shaped perforation for the engine protection was planned for the INEOS Grenadier. Of course we could have delivered these. However, in the design-in process, together with the engineers and designers from INEOS, we worked out the advantages of hexagonal perforation for this application. The achieved increase in air flow of a good eight percent has a measurable effect on engine cooling. This means the engine works more efficiently and is just as well protected against stone chips as with the diamond perforation,” says Torsten Schoew, automotive expert in the area of engine protection and cooling at Schäfer Perforated Sheets.
The challenge in producing the hole pattern Hv 6.0-6.7 is the ratio of hole size (6 mm), material thickness (1.0 mm) and web width (0.7 mm). The 0.7 mm fine bars must not crack during production and must withstand external influences even in harsh environments. This requires know-how and precise punching tools in the production facility, which Schäfer Perforated Sheets produces in its in-house tool shop.
Manufacturing know-how
When producing perforated sheets, metal stamps are mechanically pressed into the smooth sheet surface using pressure, which creates the specific hole patterns. Process-related breakout burrs occur on the punch exit sides on the underside of the sheet metal.
With Schäfer perforated sheets, these are deburred in a further operation as standard during production. Only now is further processing using chemical or electrochemical processes recommended for permanent corrosion or oxidation protection of the perforated sheets. High-quality perforated sheets are a prerequisite for long-lasting solutions.
Among many other steel grades, Magnelis® flat steels are processed by ArcelorMittal, which are also available through EMW. Magnelis® flat steels are characterized by self-regeneration on cut edges and are therefore particularly corrosion-resistant. The perforated sheets, which are manufactured with a wide variety of hole patterns, can be provided with the common RAL colors at the factory.
The long-term corrosion resistance was checked and certified by independent third parties using a salt spray test.
Complexity of the products
The company's product range includes over 400 immediately available hole patterns, which are designed as round, square, diamond, long or hexagonal holes. Steel, stainless steel, aluminum, copper, zinc, brass and plastic are used for processing. An in-house design department with application specialists is responsible for developing customer-specific patterns and optimizing high levels of complexity.
This means that almost all conceivable applications and design wishes can be realized. In addition to perforation, Schäfer Perforated Sheets provides a wide range of processing services, in particular lasering, edging, notching, punching, degreasing, powder coating, painting and anodizing. This means that ready-to-install components can be delivered just-in-time.
