Paper tray product with flanging shape always show burrs on the edge. It can be explained: as flange structure paper tray is formed with flat edge, when paper pulp is sucked up by vacuum pump, on the edge of stainless steel filter net, fiber will be gathered on the edge with irregular shape, this is formed naturally, after being formed and flanged, the burr part will be turned into the side with no influence to the package, it shall not be used as the manufacturing controlling part in industry. Customer can remove the burrs by trimming process, using die cutting to achieve the required surface quality.