Deformation in shear slitting of polymeric webs

Abstract

Shear slitting of a 25.4 μm thick polypropylene web was conducted on a laboratory slitter using a pair of rotary blades at a constant speed up to 5.08 m/s under controlled tension. The effect of web speed on the slit-edge burr height of the web is investigated for the thick polypropylene web. A profilometer was employed to measure the edge profile. Experimental results indicate that the burr height decreases with web speed when other slitting parameters are fixed. To overcome the difficulty in observing the in-situ shear slitting process of the polypropylene web, a rubber sheet was also used in the present study for the observation of the deformation process during shear slitting, and the surface deformation field of the rubber was measured by a digital image correlation method. The finite element simulation of the early stage of rubber slitting process was performed using commercial ABAQUS code and numerical results are in good agreement with those observed in experiments. The experimental observation and the numerical simulation show that shear slitting of rubber initiates with an indentation process, followed by deformation localizations around the slitter blades; the final stage is a tearing process.