Patent ID: 7223087
Filing Date: 2007-05-29
Classification: B29C

Abstract:
1. An apparatus for heating a work material using microwave radiation in a resonance cavity of a microwave oven, the work material to be molded into a workpiece, said apparatus comprising a mold positionable in the resonance cavity of said microwave oven; said mold comprising first and second end mold members and a circumferential mold member surrounding a mold cavity; said first end mold member moveable toward said second end mold member within said circumferential mold member to compress the work material in said mold cavity; said circumferential mold member including a metal sleeve extending around said mold cavity and a layer of microwave absorbing material positioned on an outer surface of said metal sleeve; said first and second end mold members including a layer of microwave absorbing material; wherein an effective thermosensitivity of each of said layers of microwave absorbing material of said circumferential mold member, said first end mold member and said second end mold member are approximately equal, such that exposing said mold to microwave radiation in said microwave oven results in relatively equal heating rates of each of said mold members; wherein the effective thermosensitivity of the layer of microwave absorbing material of each mold member is equal to the dissipation factor of the microwave absorbing material divided by the product of its dielectric constant, density and specific heat and multiplied by the ratio of the mass of the respective layer microwave of absorbing material over the total mass of the respective mold member.