A novel superplastic dieless drawing using fracture phenomenon for fabrication of metal tubular microneedles

A new dieless drawing using fracture phenomenon is proposed to fabricate superplastic microneedles with ultrafine tip diameter. The fracture type of high ductility after superplastic deformation is used for fabrication of ultrafine tip. The tapered shape of the microneedles is controlled by varying the drawing speed. Shape control was realized using a fixed water-cooling coil for a needle length below 70 mm. Heating temperature and drawing acceleration affect the tip outer diameter. The microneedle with a tip outer diameter of about 50 μm is fabricated under optimized drawing conditions. The fabricated microneedles can be used for medical and biotechnology applications.