FE analysis of size effect on deformation and heat transfer behavior in microtube dieless drawing

In this study, size effect on the deformation and heat transfer behavior of microtubes in a dieless drawing process is investigated using finite element (FE) analysis. A FE simulation with coupled thermo-mechanical analysis is performed by considering the strain rate sensitivity of the tubular materials. Tubes with outer diameters of 50, 5 and 0.5 mm were used in the FE analysis to investigate the size effect of drawing speed on the deformation and heat transfer behavior in dieless drawing. We found that heat is not conducted from the outside surface to the inside of a macroscale tube in the case of very high-speed drawing. In contrast, the temperature of the outside surface and the inside of microtubes can be increased rapidly due to the size effect at the microscale. Therefore, high-speed drawing can be realized for the dieless drawing of microtubes. From the above results, the effectiveness of dieless drawing for microtube has been demonstrated.