High-speed cutting of foods: Cutting behavior and initial cutting forces

The viscoelastic properties of foods determine deformation, fracture and friction during industrial cutting applications and substantially affect the cutting behavior, especially at high cutting velocity. Using a custom-built high-speed test station the cutting behavior of representative foods (either based on a protein network, plant tissues and sugar based confectionary) and food models on elastomer basis was investigated at a cutting velocity ranging from 10−4 m/s up to 10 m/s. On the basis of cutting force data and dynamic mechanical analysis performed between 1 rad/s and 100 rad/s, the cutting behavior of the systems was investigated. In general, the cutting force profiles depended on cutting velocity and could be related to deformation characteristics that were measured in dynamic mechanical analysis (except for plant tissue whose inherent composite structures seem to contribute to brittle behavior at each cutting velocity). Sugar based confectionary showed a strong rate dependence with brittle fracture and splintering in the high-speed region. For all systems except plant tissues a velocity dependent deformation cutting parameter, derived from the initial cutting forces, coincides with the power law frequency dependence of the complex modulus. This relation was used to build a model approach with which the pre-crack cutting forces at high-speed cutting velocity can be predicted with commercially available standard testing machines.