A structure and method are provided for forming a box for molding an article for use in casting. A wall defines a cavity formed in a shape of the article and configured to receive a material for forming the article. A rim is disposed around the wall and extends therefrom defining a hollow back on an opposite side of the wall from the cavity. A lattice structure formed in the hollow back and is connected with the wall and with the rim. The box may be formed by additive manufacturing.