The effects of surface roughness on the hemming process of aluminum thin plates

Hemming is a manufacturing process in which a panel is folded onto itself or onto another panel. In this work, the effect of the panels’ roughness conditions on the hemming process is numerically and experimentally studied. Numerical simulation of the die hemming process was performed including bending, pre-hemming, and final hemming. For the numerical analysis, internal and external panels were simulated using a Barlat 3 parameters material model and 6061 aluminum mechanical properties. The panels’ roughness was simulated based on the mean roughness obtained from experimental measurements. The extraction force generated by the external panel on the internal one was experimentally and numerically obtained, as a function of the punch force applied. Experimental results from roughened panels show that the extraction force decreases as a function of the punch force applied. Finally, the experimental results were compared with the numerical ones; showing differences around 8.04% and 6.80% for the non-roughened and roughened panels, respectively.