PRODUCTION OF MEMBER HAVING VENT HOLE

摘要

PURPOSE:To absorb excess melts of core materials into a porous body and form vent holes of a uniform hole diameter by providing the porous body in parallel with the spiral windings wound around the core materials. CONSTITUTION:Wires 5 of metal or ceramics having a m.p. higher than the m.p. of a core material 4 is wound spirally around a metallic wire constituting the core material 4, whereby a secondary wire material 6 is formed. The wire materials 6 are juxtaposed around a porous foamed metallic wire 7 and are bundled together. The excess melts of the cores which cannot be fully absorbed by the clearances between the windings and the secondary wires alone are absorbed by the porous body.