Method for forming an outsole with an insert on an article of footwear

A method for forming an outsole of an article of footwear, comprising the steps of:

• (a) preparing an upper with an insole and a peripheral wall;
• (b) preparing an insert that has a top wall, left and right side walls, and front and rear side walls extending between the left and right side walls;
• (c) forming a releasing film on at least one of the left and right side and the rear side wall of the insert;
• (d) preparing a mold that has an upper mold part with a last, a lower mold part, and a pair of side mold parts;
• (e) placing the upper and the insert in a mold cavity confined by an assembly of the last and the side mold parts in such a manner that the upper is mounted on the last, that the releasing film is in contact with at least one of the side mold parts, and that the insert is vertically spaced apart from the insole of the upper by a gap;
• (f) filling the mold cavity and the gap with a foamable material in such a manner that the foamable material surrounds the insole of the upper, and the front side wall and the top wall of the insert;
• (g) closing the mold cavity using the lower mold part, and subjecting the foamable material to expansion, cross-linking, and molding so as to form the outsole with the insert inlaid therein;
• and
• (h) removing the releasing film from the insert to expose said at least one of the left and right side walls and the rear side wall of the insert from the outsole.