Extrusion: Software Simulates Extrudate Cooling and Shrinkage
Eliminates need for processors to purchase two separate software packages for simulating the flow inside the die and for predicting the extrudate cooling.
The new version of Plastic Flow’s polyXtrue software allows users to accurately simulate extrudate cooling and corresponding extrudate shrinkage. This means there is no need for processors to purchase two separate software packages for simulating the flow inside the die and for predicting the extrudate cooling.
The new version now includes the effect of shrinkage due to extrudate cooling as well as the effect of non-uniform exit velocity to accurately predict the extrudate distortion and the shape of the final extruded product.
For an accurate analysis of extrudate cooling, shrinkage, and distortion, the new version of polyXtrue starts by treating the polymer as a melt near the die exit, but then transforms the analysis to treat the extrudate as a solid at lower temperatures away from the exit. This unified fluid-solid analysis of extrudate gives an unprecedented accuracy in the predicted temperature and distortion of the extrudate. The algorithm for the post-die analysis has been completely revamped to simulate this coupled fluid-solid system while also improving the computational speed of the software. Furthermore, the flow in the calibrator as well as in the post-calibrator region is included in the analysis.
Users can continue to run the latest release as an add-in inside SolidWorks and Inventor. The optiXtrue software then allows you to automatically optimize your extrusion dies by parameterizing the critical die dimensions in either of the two geometric modeling software packages. Many of the other important features from the previous versions of polyXtrue, such as accurate prediction of layer structure in the final product; accelerated computation speed using the Graphics Processing Unit (GPU) of your computer have been further improved in the new version.
The graphical user interface (GUI) of the software has also been updated with a large number of new features to make the software more effective and even more user friendly.
This release of polyXtrue is also available as the Pay-Per-eXecution (PPX) version. The free PPX version of polyXtrue can be downloaded here.
Putting one or two vents between the feed throat and die is a good way to remove moisture, trapped air, and other volatiles from melted plastic as it moves through an extruder.
All extrusion processes depend to some degree on the melt strength of the polymer, and this property is generally a no-show on data sheets.
A poorly designed profile die—one that does not permit the part to be extruded with the same dimensions from run to run—coupled with a lack of understanding of the extrusion process, is a recipe for scrap generation.