Design, simulation and analysis of extrusion process for thermoplastic rigid PVC profile to optimize the design of the die and the parameters
ABSTRACT The objective of the present work was to verify and optimize the die design to manufacture a thermoplastic profile in rigid PVC using the simulation of the flow in the mentioned matrix through the use of Computational Fluid Dynamics (CFD) and through tests in extrusion, using an experimental calibrator, the required geometry and dimensions were obtained. The material used was a rigid PVC compound which is difficult to process because of its intrinsic weakness, since it degrades to 140ºC. By means of a special capillary rheometer the rheological data k and n of the Power Law model were determined, which was used as input variables in the software along with the flow channel geometry in the head. The geometry is drawn using computeraided design software in three dimensions (CAD-3D). The calibrator was designed and drawn in CAD-3D software and then built, mounted on the extruder. Extrusion was performed with the process parameters: flow rate (screw speed) and temperature of the material used in the simulation software. The results of the extrusion were compared: geometry and final dimensions of the profile, mass flow, pressure and temperature in the head with those obtained by the simulation, being the same satisfactory. From the simulation, the optimum distance at which the deformations of the cast profile at the exit of the die determined was minimal and allowed to be calibrated to the required profile dimensions. In addition, the velocity distributions and shear deformations were obtained, which gave an indication of the dimensional and geometric and mechanical physical properties of resistance to the stresses of the profile, so that it was possible to determine that the design of the existing head is not right.