The cutting of foods is characterized by deformation, fracture and friction process-es, and the viscoelastic properties of the cutting materials determine their rate-dependent cutting behavior. This is responsible for uncontrolled fracture and defor-mation events with increasing cutting velocity. There is a significant information deficit regarding the assignment of material properties and cutting parameters, as well as re-garding a process description for industrial high-speed cutting.
The aim of the work is the analysis of the velocity-dependent cutting behavior of foods up to the high-speed range. The focus is on the deformation and fracture phenom-ena, analysed by methods of classical material analysis but also associated cutting exper-iments performed in the range from low to high cutting velocities. For high-speed analy-ses, a test station enabling cutting velocities of up to 10 m/s was designed. To identify relevant material and cutting parameters and to establish a systematic experimental pro-gram, elastomer-based model systems with controllable viscoelastic profiles were devel-oped. The results of the respective investigations were further verified for foods. The ve-locity-dependent deformation behavior during cutting could be described by dynamic-mechanical material analyses in the frequency range. Cutting force slopes at the begin-ning of the cutting process correlated with the complex moduli and were furthermore dependent on the cutting velocity; this dependency corresponded to the frequency be-havior from material analysis. The fracture properties could be attributed to ductile (poly-meric systems) or brittle behavior (cellular plant systems). Confectionary products had a strong temperature- and time-dependent behavior with ductile-brittle transition within the experimental conditions.
The results obtained demonstrate that there is a significant relationship between viscoelasticity and velocity-dependent cutting behavior. They allow a phenomenological process description of high-speed cutting and can be used as a basis for the balancing of cutting forces and as input parameters for numerical analyses of the cutting process.