Size Effects in Micro Forming
Size effects are effects which might occur, if the dimensions of a forming process are scaled up or down. They might enable or disable the application of a process in the micro range. Based on the systematic order of size effects, which defines density, shape and structure effects, one example for each group is given. A density effect, which occurs in Tiffany structures, explains the changes in forming behavior of foils with respect to the forming limit diagram. The feasibility of a new heading process only in the micro range is due to a shape effect, driven by the surface energy. The changes in the tribology in deep drawing by a structure effect, known as closed an open lubricant pocket model, can be explained only if one takes the temperature dependence of the viscosity of the lubricant into account.
J.R. Duflou, R. Clarke, M. Merklein, F. Micari, B. Shirvani and K. Kellens
F. Vollertsen "Size Effects in Micro Forming", Key Engineering Materials, Vol. 473, pp. 3-12, 2011