Aluminium foil demonstrates some distinct properties when used in the construction of honeycomb cored panels and structures. Sandwiched between aluminium sheets, the layers of alufoil, joined together and expanded into an open-celled honeycomb format, provide an extremely strong yet light core.
The resulting panel out-performs competitive materials in strength to weight ratio and lightness, also in terms of rigidity and flatness under load. The surfaces can be finished according to the needs of the application – aluminium alloys for aircraft components, metal tread plates for floor panels, marble or stone for interior décor, or external cladding, paint or plastics materials for displays or cabinet enclosures. This material enables architects to lighten building structures and foundations, engineers to save weight in all types of transport – ships, planes, trucks and cars – due to the properties of the aluminium foil core materials.
Lightness, durability and flatness means alufoil honeycomb-cored panels are specified for architectural cladding in many forms. Decorative bonded skins involving marble, granite, untreated or anodised aluminium (in colours or uncoloured) or coil coated lacquers, etc. make these lightweight panels suitable for all types of building – commercial, industrial or domestic. The resulting weight economies lead to significant cuts in the load bearing structure and in foundation work. These can mean big reductions in the amounts of materials needed and the costs of construction. Honeycomb panels also add sound insulation properties to exterior cladding.
Outstanding flatness makes alufoil-cored a primary choice for fascia panels and road signs. Aluminium honeycomb panels can be shaped and formed to make curves and bends. Lightness helps in the handling and assembly while its durability means these signs and displays have a long useful life. Maintenance, when required, is minimal. For interior displays and exhibition stands great savings can be achieved by incorporating lightweight, long life and durably finished honeycomb enclosure panels.
All aluminium applications in the transport sector using strong and durable honeycomb panels save deadweight and add to the amounts that can be carried. This, in turn, saves on vehicle usage, fuel consumed and emissions. Future lowe mission and alternative fuel systems are likely to require the construction of vehicles to an absolute minimum of weight. Aluminium foil honeycomb offers many solutions in this respect.
Aluminium honeycomb material can provide a high level of energy absorption when designed into impact protection components for vehicles. Studies carried out with car manufacturers have demonstrated that the honeycomb-based elements have a constant strength and a controlled level of deformation. In a longitudinal force experiment the deformation elements were compressed to 30% of their original length and absorbed large amounts of impact energy, reducing the effects on other structural components.
A wafer block of aluminium foil core material is stretched into a sheet of hexagonal structure on purpose built, CNC equipment to give a consistent cell dimension. The walls of the cells can be micro-perforated to allow movement of air between adjacent cells, equalising pressure in environments with rapid temperature variations. The expanded core is bonded to the outer facings with a two-part adhesive which is applied in a dedicated computer controlled spray booth facility. This allows close monitoring of coat weights and accurate application to all substrates. The sandwich faces and core are laid up and accurately aligned prior to transferring, by means of roller, table to the press. The final bonding process is done on a heated, hydraulically operated press to ensure uniformity of each panel and is closely controlled to ensure reliability of the bond. The cell size, depth of material, thickness of cell walls and aluminium alloy are all varied to suit specific requirements and tailored to impart the correct, specified properties in the final manufactured units.