In this paper the authors proposes a new experimental approach to quantify the sliding of hot viscous glass on a substrate material, in conditions representative of the loading of glass gobs into forming moulds. Using a gob-loading sensor, the method consists in calculating the energy dissipated by the glass gob when crossing a feeding funnel, with a direct measurement of the velocity loss of the gob following its dynamic contact with the funnel. Experimental data combined with mechanical modelling has been performed with two funnel geometries: a cylindrical funnel and a conical funnel. Strain dissipation energy induced by the deformation of the viscous gob inside the funnel has been calculated. It is shown that the cylindrical funnel allows strain modes consuming four times less energy than the conical funnel.
