Composite stone and rigid polyurethane foam work surface manufacture involves machining panel edge to thickness, bonding on stone edge strip and molding polyurethane foam between stone panel and thin back sheet

摘要

A stone panel is cut oversize and ground to a thickness along one edge. An overwidth opposing stone edge strip(3) is bonded(2) to the edge and the panel cut to size along (3). The panel is transferred to a tool, with spacers located for positioning a thin back sheet(4), the outer surface aligned flush with (3). A rigid polyurethane foam mixture(5) is added and bonds the stone panel and (4). A stone panel is cut oversize and ground to a set thickness along one edge. An overwidth opposing stone edge strip(3) is bonded(2) to the edge and the panel cut to size along the strip, the exposed edges polished and free edges milled. The dried panel is transferred to a tool, enclosed by a frame on the free sides and spacers located for positioning a thin back sheet(4), whose outer surface is aligned flush with the outside of the edge strip. On tool closure a two part rigid polyurethane (PU) foam mixture(5) is introduced and on curing bonds to the inner faces of the stone panel and back sheet. Spacers may be either cubes, parallelepipeds or threaded sleeves or dowels. Thickness ratio of stone panel to PU foam layer(5) is 0.25 - 0.75:1. Heating and cooling elements may be incorporated in the foam. Machining of the panel may be effected at the workplace. When cutting the panel from the upper side saw depth is set so that it does not cut completely through to the underside of the PU foam. The channel created allows dust to be extracted more safely. After making the cut the remaining PU layer and back sheet(4) are cut or mechanically broken. The back sheet may be a thin wooden or chipboard sheet.