CFD-simulation is performed for an existing die to produce uPVC profiles by extrusion. Flow channel, free zone and die geometries are draw in solid CAD 3-D. Experimental determinations are performed using an extruder with a calibrator experimentally designed and built specialty for this profile. The process is performed for two uPVC compounds (mainly different thermal stabilizers) and behavior is compared between both material. Non-isothermal simulations are carried out taking into account the influence of shear rate and temperature on the viscosity of the PVC molten. Rheological testing are performed using an special rotational rheometer for PVC. Regarding of testing results is defined to use the Ostwald law model for dependence of the viscosity with shear rate. Through the simulation is possible to determine the optimal distance where the deformations due to the die swelling of the profile molten is minimal, homogeneous and allow the profile to be calibrated correctly. Also, there are determined velocities distributions across each section of flow channel, shear rates, shear stresses, temperatures, pressures and die swelling, which gave us an indication of the final physical and mechanical properties of the profile in order to improve the design of the die design and process parameters.
Finally, the simulated die swelling with the extruded one at 60 mm distance is compared for each material and it is possible to predict the behavior of the molten material at exit of die when the formulation of the compound is modified.
|Category||Short file description||File description||File Size|
|Presentation||Abstract-MSE_Tomassini_SAM-Arg._Feb.28,2018||Analysis of a die design and extrusion process of uPVC profile: 3D modeling, simulation and experimental testing.||61 KB||Download|
|Presentation||Complete work||Analysis of a die design and extrusion process of uPVC profile: 3D modeling, simulation and experimental testing||607 KB||Download|