In this paper a characteristic value should be found to characterize the fluidity of thermoplastic melts in injection moulding in practical operation. For this purpose a measurement of the filling pressure in the nozzle is executed. The nozzle-filling-pressure found in this way will be compared with other characteristic values, as mould-filling-pressure, nozzle-filling-index and hydraulic-filling-index. Particularly the nozzle-filling-pressure is considered for applicability as a characteristic value mentioned above. Analysis of occupational safety, reproducibility, and replicability should assure the possibility to apply the nozzle-filling-pressure as a value for decontrol.
If all properties are measured at one sample this method offers also the advantage to give a direct relation between the melt-fluidity, shrinkage, optic and mechanical properties.
Additional to the measurements calculations with the simulation-program MOLD FLOW are executed.
Following to this practical research a ”rheological nozzle” has been constructed and built. By measuring the pressure-difference along the nozzle-slot it will be possible to calculate the viscosity and shear rate. The viscosity-results, found out in this way will be compared with viscosity-results determined in a high-pressure-capillary-rheometer. Beside the practical measurements with the ”rheological nozzle” also calculations with the program MOLD FLOW are made to show the rheological and thermodynamic flow–characteristic in the slot core.