Of the available micro-manufacturing technology, micro-forming draws the attention of manufacturers and researchers due to its high precision, low energy consumption and low cost products with better mechanical properties. However, due to the size effect, the traditional macro-forming techniques cannot be applied to micro-forming directly. Therefore, manufacturing of micro-components is a challenging field. When the parts are miniaturized, adhesive force and surface tension play an important role. The microstructure, grain orientation, grain boundary and surface integrity significantly influence the micro-forming process. Three FCC materials (SS304) of 30, 50 and 90 µm thicknesses were selected as working material to study the size effect. The effects of thickness, surface grain, cross-sectional grain size on mechanical behaviour were investigated. The grain distribution through surface and cross section was quantified. The effect of thickness on YS and UTS at nearly same grain size was studied, and it was observed that the strength decreases with increasing thickness from 30 to 90 µm. © 2015, Springer India.