Method for manufacturing a midsole formed from two preforms

A method of manufacturing a midsole for an article of footwear comprising

• placing a first preform having a first preform peripheral flange and a second preform having a second preform peripheral flange in contact with one another in a preform recess in a first mold, the first and second preforms being positioned in a preform recess in the first mold, a first recess formed in a first portion of the first mold and a second recess formed in a second portion of the first mold cooperating to define the preform recess, the first and second preform peripheral flanges being positioned in a peripheral overflow chamber of the first mold, a first overflow recess formed in the first portion of the first mold and a second overflow recess formed in the second portion of the first mold cooperating to define the peripheral overflow chamber;
• closing the first mold by positioning the first and second portions in contact with one another;
• heating the first mold for a predetermined period of time at a predetermined temperature such that the first and second preforms expand within the preform recess and the first and second preform peripheral flanges expand within the peripheral overflow chamber to produce a midsole preform with a peripheral preform flange extending about a periphery of the midsole preform;
• removing the midsole preform from the first mold;
• allowing the midsole to further expand and cool;
• placing the midsole preform in a midsole recess of a second mold and the peripheral flange in a peripheral recess of the second mold, a first recess in the first portion of the second mold and a second recess in the second portion of the second mold cooperating to define the midsole recess, a first peripheral recess in the first portion of the second mold and a second peripheral recess in the second portion of the second mold cooperating to define the peripheral recess, and the peripheral recess extending about a periphery of the midsole recess, with a volume of the midsole recess being less than a volume of the midsole preform and a volume of the peripheral recess being less than a volume of the peripheral flange;
• closing the second mold by and compressing the midsole preform and the peripheral preform flange by aligning the first recess in the first portion of the second mold and the second recess in the second portion of the second mold and bringing the first and second portions into contact with one another to form a midsole with a peripheral flange;
• heating the second mold for a predetermined period of time at a predetermined temperature;
• allowing the second mold to cool;
• opening the second mold;
• and
• cutting away the peripheral flange of the midsole.