Sandwich panels

A sandwich panel is a structure made of three layers: low density core inserted in between two relatively thin skin layers. This sandwich setup allows to achieve excellent mechanical performance at minimal weight. The very high rigidity of a sandwich panel is achieved thanks to interaction of its components under flexural load applied to the panel: core takes the shear loads and creates a distance between the skins which take the in-plane stresses, one skin in tension, the other in compression. General information on sandwich panel structure, different sandwich core types available and the potential with respect to weight savings is available in the following reference.

Honeycomb sandwich panel has been proven as the most efficient sandwich design with respect to mechanical performance and weight. Aerospace and aircraft industry uses the honeycomb structures as they meet the tough requirements of related applications. The use of honeycomb sandwich design in more common applications has been more limited due to the batch wise manufacturing processes and hence relatively high production costs.

This trend has been changed after the company EconCore developed a continuous process of honeycomb production under the brand name ThermHex. Cost efficiency of the ThermHex process, which has been licensed by number of companies over the world, allows a very cost effective production of sandwich panel with thermoplastic honeycomb core for applications in even cost sensitive market segments such as packaging, automotive, or building & construction.

Aluminium composite panel (ACP), also aluminium composite material (ACM), is a type of flat panel that consists of two thin aluminium sheets bonded to a non-aluminium core. ACPs are frequently used for external cladding or facades of buildings, insulation, and signage. If the core material is flammable, usage may be problematic as a building material and some jurisdictions have banned their use.

Aluminium sheets can be coated with polyvinylidene fluoride (PVDF), fluoropolymer resins (FEVE), or polyester paint. Aluminium can be painted in any kind of colour, and ACPs are produced in a wide range of metallic and non-metallic colours as well as patterns that imitate other materials, such as wood or marble. The core is commonly low-density polyethylene, or a mix of low-density polyethylene and mineral material to exhibit fire retardant properties.

3A Composites (formerly Alcan Composites & Alusuisse) invented aluminium composites in 1964 and commercial production of Alucobond commenced in 1969, followed by Dibond 20 years later.

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