2016 Volume 57 Issue 666 Pages 641-647
The ratio of tooling feature size to minimum thickness becomes small in microscale products and significantly affects the deformation behavior in micro-sheet forming. In this study, the effect of this relative tooling feature size on the drawing characteristics, and effects that can improve the drawability, such as the friction holding effect, hydrodynamic lubrication effect and compression effect of blank edge by radial pressure, in micro-hydromechanical deep drawing (MHDD) are investigated by finite element method (FEM) simulation. The results show that the microdrawing characteristics in MHDD can be improved by applying counterpressure. However, the required fluid pressures for friction holding and hydrodynamic lubrication effects increase when the ratios of punch diameter and/or die shoulder radius to thickness decrease, although the compression effect of blank edge by radial pressure is independent of the relative tooling feature size. It is found that a high fluid pressure is helpful in improving the microdrawing characteristics at the microscale with a small relative tooling feature size.
