Evaluation of Voids on Shrink PVC Film

Gravure is one of the most widely used processes for printing on shrink films, the reason being its consistency for longer runs. However, such printing is accompanied by new challenges. The presence of gels, black specks and other contaminations in these films does not allow the surrounding area to print, thus resulting in print void. The occurrence of this defect in a considerable amount or size on the area of interest leads to the rejection of printed stock that involves wastage of inks, solvents and time. The research involves the investigation of the effect of gravure process variables on the minimization of print voids in Shrink PVC film. The gravure process variables viz. viscosity, pressure, speed and hardness were identified for the indirect laser cylinder. It was established that hardness had a significant impact on minimizing the voids, while viscosity-hardness interaction played another important role. The results showed the reduction in void area with lower viscosity, higher pressure, lower speed and higher hardness.