The influence of recycling on the viscosity of polyamide 6 and a general modeling approach

Abstract

The multiple processing and use of regrind material of plastics are widely used in the plastics processing industry. The subsequent changes in material characteristics, certainly in the viscosity of the polymer melt, have been analyzed and are well known. However, to quantify the changing viscosity, a general modeling approach is necessary using a low quantity of lab measurements. For the example of a polyamide 6, rheological measurements have been performed and a general modeling approach for the viscosity based on the Carreau model has been developed. The verification of the modeling was successfully proven by comparing additional viscosity measurements with model prediction results.

Self‐optimization of the V/P switchover and packing pressure for online viscosity compensation during injection molding

“…These changes cause remarkable fluctuations in the flowability of the plastic melt. [8,9] The conventional approach to stabilize the process fluctuations is to adjust the machine parameters based on experience after halting the continuous production. [10] As a result of this disruption, thermal equilibrium in the plastination unit and mold should be reestablished and larger errors might occur.…”

A novel strategy to determine the optimal clamping force based on the clamping force change during injection molding

“…Kitayama investigated the relationship between the clamping force setting and weld lines on molded parts and discovered that appropriate clamping force setting may reduce the amount of weld lines. [ 13 ] In other words, besides parameter deviations, material fluctuations and the wear of plasticizing parts, [ 14, 15 ] excessive clamping force will also result in bad quality of molded parts. [ 8 ] However, some failures of the machine, such as deformed platens and fractured machine frames, come with molding defects and mold failure.…”