Control of Final Part Dimensions in Polymer Extrusion Using a Variable-Geometry Die

Abstract

Parts made via polymer extrusion are currently limited to a constant cross section. Additionally, the process is difficult to control, so desired final part dimensions are often achieved via a manual trial-and-error approach to parameter adjustment. This work seeks to increase the capability of polymer extrusion by using iterative learning control (ILC) to regulate the final width of a rectangular part through changing the width of a simple variable-geometry die. Simulation results determine the appropriateness of the learning algorithm and gains to be used in experiment. A prototype die on a production extruder was used to demonstrate the effectiveness of the approach. These experiments achieved automated control over both gross change in shape and final part dimension when the puller speed was held constant, which has not been seen previously in the literature.

Augmented Reality, Cyber-Physical Systems, and Feedback Control for Additive Manufacturing: A Review

“…In [67], a multivariable adaptive and control scheme has been proposed for controlling both the temperature and the thickness of the extrudate. The possibility to directly control the final part geometry in order to avoid the manual adjustment of the process parameters by technicians has been investigated in [68]. The proposed control strategy relies on an iterative learning controller and its relevance was demonstrated for the regulation of the width of a rectangle.…”