foam thermoplastic injection molding apparatus and method produces structurally superior foam injection molded products . the process includes plasticating solid polymer to a polymer melt ; accumulating the melt in an accumulator having a telescoping inlet , which allows the first melt which enters to be the first to leave the accumulator ; combining a preselected amount of melt with a preselected amount of gas in bubble form to form homogenized polymer foam ; shearing the homogenized polymer foam to reduce the size of gas bubbles ; and injecting the polymer foam through a special gate assembly into a mold . the gate assembly has a removable nose which remains with the mold , allowing the foam to expand within the mold but not allowing the foam to escape the mold . the process and apparatus allow low molded - in stress products to be produced , and can process recyclable thermoplastics , either single materials or mixtures . thus , no segregation of materials is required .