2017 年 58 巻 672 号 p. 72-77
In this study, a new microtube hydroforming （THF） system utilizing ultrahigh pressure to fabricate cross-shaped microcomponents is designed and developed. The micro-THF die assembly employs a new type of split die and has a die housing with a flow channel of fluid medium to apply ultrahigh pressure into a tube through micro notches on an axial punch. A phosphorous-deoxidized copper tube with an outer diameter of 500µm and thickness of 100µm is used for cross-shaped micro THF experiment. Finite-element analysis is carried out to confirm and clarify the deformation characteristics, forming limit, and suitable forming conditions inoder to enhance the protrusion height of cross-shape forming. Consequently, a cross-shaped microcomponent with an outstanding bulge height of 1. 6 times the outer diameter is successfully fabricated experimentally.