Considering that wood materials and regenerated wood materials have certain characteristics of thermal expansion and cold contraction, a hollow area is properly reserved inside the door, that is, semi-solid filling, which can better ensure the stability of product quality, so we do not advocate you choose full solid fill inside for door core. You can choose Tubular Core Plate, Plywood Semi-Solid Filling, MDF/HDF Board Semi-Solid Filling, Solid Wood Strip Semi-Solid Filling as the door core material, also can with the honeycomb paper, aluminum honeycomb.