The surface metal of this sandwich panel is high-quality fluorocarbon aluminum, painted steel, or other precision profiled metal plate. After rolling molding, inject the foam fireproof polyurethane with high pressure, or cut the rock wool/glass wool into stripes and then turn 90 degrees (making the fibers perpendicular to the metal surface), bonding it strongly with the metal plate. The high-density rigid foam undergoes a unique tongue and groove filling process, with the long precision double track controlling the molding compound, forming nice, smooth, tough building color plates.