the present invention relates to molds and mold portions that comprise or have integrated therewith a resinous material and comprise at least one electromagnetic actuator imbedded in the resinous material , so as to be capable of further forming the at least one precursor area of the work piece . the resin is used to locate the coil , and clamps or other restraints preferably are used to keep the weaker electrically insulating resin out of a state of large tensile stress or strain , which may cause it to fracture . preferably , the resinous material comprises metallic flakes imbedded therein .