Cement, sand and other reasonable ratio, through the manhole cover mold, pressed by high pressure, with compression and strong, high bearing capacity, generally circular. Save material, the same large area, with less material, round can reduce sewer cover was stolen pedestrian hit look and fall due to the possibility of sewer mouth is round. Professional plastic mold making factory Hebei dragon mold factory Professional build all kinds of tile equipment mold, road calculus mold, grass brick, rubber molds, etc., please contact contact set.