A thermally conducting and electrically insulating overmold encapsulates and supports an actuator coil in a disc drive assembly. The overmold is made from a base resin mixed with a ceramic filler compound such as boron nitride, alumina, aluminum nitride, magnesium oxide, zinc oxide, silicon carbide, beryllium oxide, chromium oxide or some combination thereof. The base resin is preferably polypheneline sulfide. Glass filler and/or a coupling agent are also preferably added. The overmold reduces off track read/write head position errors due to popping caused by thermal expansion and contraction of the actuator coil.