Patent ID: 8236212

Claim:
A method of making a molded article during a single heating cycle, comprising: providing a flow molding apparatus comprising a first mold section and a second mold section; selecting a foam material from which to form the molded article, wherein the foam material comprises a formable material mixed with a blowing agent; placing the foam material in the flow molding apparatus such that a first surface of the foam material is in contact with the first mold section and a second surface of the foam material is in contact with the second mold section; adjusting a characteristic of the second mold section so as to control a thickness of hardened skin to be formed on the second surface of the foam material; and heating the foam material in the flow molding apparatus by applying an alternating electric field across the foam material such that, at the end of the heating cycle, (i) the first surface of the foam material exceeds a decomposition temperature of the blowing agent and is blown and (ii) the second surface of the foam material remains under the decomposition temperature of the blowing agent and is not blown to thereby form the thickness of hardened skin on the second surface of the foam material.