SIGMA – Simulation of Co-rotating Twin-Screw Extruders

SIGMA is a joint research project currently 11 industrial companies and the KTP of the University of Paderborn participate in. The software is a program which simulates compounding and processing methods on co-rotating twin-screw extruders. The aim of the development is to enable a faster and more global evaluation of the machine behavior and thus to optimize the barrel and the screw configuration as well as the process parameters. This aim is achieved by using mostly analytical and closed equations. Calculation-intensive numerical processes are neglected as far as possible.
Calculation possibilities:

Currently, in SIGMA the following calculations are possible:

  • Pressure and filling degree calculation
  • Melting calculation
  • Temperature profile calculation
  • Calculation of the power consumption
  • Calculation of the residence times and
  • Calculation of the degree of dispersion
Figure 1: Graphical user interface
figure 1: Graphical user interface
In addition to the calculation of "pure" polymers models to estimate the behavior of polymer blends and polymer-filler compounds are implemented in SIGMA. With SIGMA premix as well as split-feed processes can be simulated.
Calculation process

Figure 2 depicts the calculation process with which SIGMA works. The central element of a simulation is the pressure-filling degree calculation, the melting and the temperature calculation. On the basis of these calculations all other necessary parameters to evaluate and optimize the screw and barrel configuration can be calculated.
Figure 2: Calculation process
figure 2: Calculation process
Simulation results

The results of the simulation calculations can be graphically depicted in form of diagrams or tables. The graphical output shows the profile of a parameter along the screw length. Thus, single screw zones can be evaluated. On the basis of these findings simple modifications can be made on the configurations if necessary. Figure 3 and 4 show an example of the pressure and filling degree profile or respectively the melting profile of such a simulation calculation.
Figure 3: Pressure- (red) and filling degree profile (blue)
figure 3: Pressure (red) and filling degree profile (blue)
Figure 4: melting profile (red)
figure 4: Melting profile (red)
To compare and evaluate the effect of different influencing variables a so-called batch module is implemented in SIGMA. In it all parameters influencing the process can be varied. All variations of the process are calculated and afterwards depicted in a so-called multi graphic.
Technical details

Supported barrel elements:

  • Standard barrel
  • Feeding barrel
  • Venting barrel
  • Measurement plates
  • Supporting plates

Supported screw elements:

  • Conveying and reconveying elements
  • Pushing flight elements
  • Kneading blocks
  • Shouldered kneading blocks
  • Eccentrical kneading blocks
  • Screw mixing elements
  • Tooth mixing elements
  • Blister elements
  • Distance elements
  • V-Mixing elements
For further questions about SIGMA, please contact Mr. Tobias Hallmann.

Demo

Anhänge
application/pdf iconSIGMA-Flyer_English.pdf