Repairing and Sanding
After the core is hot pressed, the veneer core is not ready for direct laminating face and back veneers. China plywood usually laminates thin hardwood veneer of 0.2mm to 0.3mm, even 0.4mm is rare, so the the platform has to be extremely flat, consistent, and with no open defects. This is the process to make sure of that, use putty to fill the gaps, fell off knots, missing woods etc. Then both faces of the panel are sanded and gauged in order to eliminate superficial defects and get the required thickness.