Liquid CO2 as a blasting media for cutting process

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Waterjet cutting uses abrasive media for improving the cutting performance. Residues of the abrasives and the wetting on the workpieces are limiting the usage, especially for cutting medical components. This motivates the investigation on new cutting processes. The approach of this project is the use of a liquid CO2 jet for cutting operations. Pre tests have shown that a two-phase CO2 jet can be used for cutting different materials. The goal of this project is to determine principles of the generation and stabilization of the CO2 jet as well as the identification of the jet and the cutting properties. For this purpose the CO2 will be pressurized, tempered, conducted through a nozzle and eventually aimed at a specimen with different hardness. Under ambient conditions CO2 can only exist in the gaseous phase, when in thermodynamic equilibrium. Hence, knowledge about metastable condition during the phase change is of vital importance. Therefore, the process during the expansion and in the free jet will be investigated by imaging systems. By variation of pre- and postexpansion conditions the free jet should be relatively long, up to several centimeters. With finishing this project the thermo- and fluiddynamically principles of this new cutting process are known and the boundary condition for the design of a cutting system are determined scientifically.