Cutting resistance of soft materials: effects of blade inclination and friction

In cutting soft elastic materials, friction is often the most relevant term of the total applied force, and techniques to minimise the required effort involve the restraint of frictional dissipation. It is well known from practical experience that cutting is made much easier if performed with a combination of slicing and pushing. A slice-push effect, known to reduce the cutting force, can be introduced by skewing the blade with respect to the travelling direction of the blade itself. The observed drop of the required force is connected to the competing dissipative contributions, with frictional dissipation being reduced at larger inclination angles. This study reports the results of several cutting tests on soft elastomeric plates, in which we have recorded the experimental force-displacement curves during the insertion of sharp stainless-steel blades. An energy-based model is employed to discern the different contributions to the measured force in the various stages of the cutting process, with particular focus on the steady state initiated after full penetration of the blade. The effects of the inclination angle of the blade are discussed with respect to the steady state force obtained from the experiments.