Novel prediction model for microforming limit curves considering material inhomogeneity based on surface roughening

This paper proposes a novel microforming limit curve (MFLC) prediction model that accounts for surface roughening and suggests appropriate surface roughness indices for use with the model. Parallel calculations of the Parmar, Mellor, and Chakrabarty (PMC) model and Marciniak–Kuczynski (M-K) model define the switching point of the dominant phenomenon. The potential for high-precision forming limit prediction for micro-precision presses is demonstrated based on comparisons with experimental values for pure aluminium foil. The proposed model demonstrates MFLC predictions with fine precisions by applying the maximum valley depth as a surface roughness index for pure aluminium foil.