Patent ID: 9688054
Date: 2017-06-27
CPC Classifications: B21D,B32B,F01N,Y10T

Claim:
1. A multi-layered composite panel, comprising at least two sheets of thin plates, wherein the two sheet of thin plates include continuous waveform patterns having the same pitch and different heights in one direction and are overlapped, and an air layer is formed between the overlapping thin plates; orthogonal pressing portions, which divide the waveform patterns on the top and the bottom of the thin plates into the unit of triangle-patterned cell by being pressed orthogonally to cross each other on the top and the bottom of the thin plates overlapping in the orthogonal direction crossing the direction of the waveform patterns, are formed; and an undercut portion is formed by pressing the centers of both sides connecting a groove and a ridge of each cell on the top and the bottom of the thin plates with opposite orthogonal pressing portions.