2023-03-18
An example of the difficulty a simulation program can have to accurately predict the melting section performance of the twin-screw compounding process, as well as the misleading information that can be provided is shown in Figure 13 a-d. The basis for this inaccuracy can be twofold. First, the algorithm for polymer melting may be inadequate. The various calculations based on the influence of extruder operating conditions and material parameters may not have the correct balance. In addition to the model algorithm, the correct input data is critical. While it is relatively easy to provide extruder operating data, quality material data is less readily available. For example, the initial particle size of the polymer will have an influence on melting. One can measure solids flow, heat transfer, coefficient of friction etc. in the lab, but under actual dynamic conditions, there are innumerable uncontrollable influences such as fluidization that impact actual heat transfer, coefficient of friction, etc.
https://www.extruder-service.com/equipment/
The Figure 13 sequence depicts a comparison between data derived for melting HDPE based on a simulation and an actual ZSK 92 run. The percent melting of HDPE on the ZSK 92, as well as the melt temperature are almost identical between the lab extruder run versus simulation software. However, the calc