an improved mold frame for making a fast thermal response mold is disclosed . the mold frame has a plurality of rows with each row having a plurality of cavities . the mold frame is constructed of two half - molds , each half - mold containing an upper and lower plate vacuum brazed together to form flow channels that allow thermal mediums to pass in close proximity to the cavity . without any direct contact between the flow mediums and the cavities the necessity for o - rings is eliminated . without o - rings the compression molding of thermoplastic materials may be at temperatures greater than 300 ° f .