DOI link for Manufacturing
This chapter briefly describes three common molding processes used for the production of molded outsoles: compression molding, injection molding, and open pour molding. It also provides some examples of how some molded outsoles are trimmed or cut, and how those and other factors might result in variations between footwear out-soles of the same brand, size, and design. Compression molding is an "open-mold" process, meaning the mold is open at the time the preweighed soling material, sometimes referred to as a biscuit of rubber or preform, is placed into the mold cavity. Many outsoles are produced using one color, but compression molds are often designed to allow for the production of multiple colored outsoles. Many molds have thin metal dams that separate design sections. To reduce molding time, compression-molding operations often remove solid rubber outsoles from the mold slightly early. The outsoles will be very hot and will continue to "cook" for a short period of time.