Slicing Soft Materials

We experimentally study the slicing of soft materials. We use a rheometer to press a circular cutting tool into these materials (a steel “cookie cutter”) at a controlled rotation speed and controlled speed in the normal direction. Typical rates are 100 rad/s angular speed and 10 microns/s normal speed. The rheometer allows us to measure the normal force and torque required to press the cutter through a material. The soft materials we use to experiment with are mainly Styrofoam and Clay. From examining the fluctuations of torque and normal force over time, we find that the most effective cutting occurs with slower normal speed, and that cutting is less sensitive to the rotation rate of the cutter.