A sandwich panel is a structure made of three layers: a low-density core ( polypropylene Honeycomb，PIR, mineral wool, XPS), and a thin skin layer bonded to each side. For example, the body of an RV is sandwiched between materials such as PP honeycomb, XPS (extruded polystyrene), PU (polyurethane) or foam, so it is called a "sandwich" body.
The sandwich body structure includes "external panels + sandwich core materials + internal panels". It sounds simple, but in reality, it is much more complicated.
Frame
First of all, as the body structure, the sandwich body must have a skeleton, and the lightweight wooden structure has become the preferred material. It can also be said that the wooden frame is the foundation of the sandwich body.
Wooden materials are used for the floors and interior walls so that the entire structure is stable and the wood edges can be easily connected.
But why has the use of wood materials gradually reduced in mid- to high-end RVs?
Many manufacturers use welding to connect wall components during the production process. If the bottom surface is also made of artificial materials instead of wooden materials, the entire car body structure is welded. This method is used to prevent the tyres of the RV from hitting the rocks causing bumps and making a "crunching" sound.
Core material
There is core material in the middle, which is responsible for thermal insulation and sound insulation. The insulation effect of the insulation material is certainly important, but the hardness of the insulation material is also important. RVs sometimes have leakage problems. For example, when the outer wall material ages, it will cause rainwater to penetrate into the insulation material layer. Plastic honeycomb panels have thermal and sound insulation effects because of their special honeycomb structure. At the same time, the hardness of their composite materials is better than other sandwich materials such as foam.
External Material
The external material, generally uses high-strength, light-weight fiberglass or aluminum-plastic panels.
The sandwich structure is generally used for the side walls and roofs of RVs. Its functions are wall support, heat insulation, sound insulation and noise reduction, weight reduction, etc. Because it undertakes so many functions, it is difficult for a single material to meet many requirements. Plastic honeycomb composite sandwich panels are the preferred material for weight reduction and reinforcement of RVs, so they are increasingly used in the transportation industry.