PRODUCTION OF FINE-HOLE TUBE

PROBLEM TO BE SOLVED: To obtain the fine-hole tube typified by a feed tube, high in inner face precision, which a nonuniform strain hardly formed in the sectional shape of the inner space even by bending by forming a metallic coating film on the core surface and removing the core while leaving the coating film. SOLUTION: A rod-shaped core material 4 of specified length is attached to the rotating jigs 8 and then dipped is an electroless Ni plating tank to form a first metallic coating film on the core material 4 surface. A rotating shaft 7 is taken out from the electroless Ni plating tank and fixed to a driving motor 9, the core material 4 is used as the negative electrode 5 of an electric caster and dipped in an Ni electroless plating tank 1, and a current is applied between the positive and negative electrodes, the core material 4 is simultaneously rotated in an electrolyte 2 by operating a rotating mechanism 6 and let stand, and a second metallic coating film is formed on the surface of the core material 4 as the negative electrode. Subsequently, the core material 4 is taken out from the plaing tank 1, detached from the jigs 8 and attached to a core remover, and the core is wound and removed leaving metallic coating film.