Collaborative Research: Variable Geometry Dies for Polymer Extrusion

该补助金提供资金开发用于挤出复杂塑料零件的可变几何模具。与大多数现有的聚合物挤出模具不同，它们具有单一的固定几何形状，设计技术将被创建以构建在不同形状之间变形的新型移动模具。在挤出过程中多个致动器的协调将在形状上施加这些变化。致动器位置将被优化，以提供抵抗挤出机内相当大的压力负载所需的机械优势。优化将通过考虑许多设计约束的遗传算法来完成，这些约束包括避免移动部件的干扰、消除对熔融塑料流动的阻碍、实现合理尺寸的模具以及最小化致动器功耗。实验工作将开发新的方法来管理模具内的熔融塑料由于其运动部件的泄漏。原型可变几何模具将建立和测试的生产挤出机由工业合作者操作。验证实验将得出模具几何形状，挤出机螺杆速度和塑料温度之间的经验关系，以提供生产无缺陷部件的过程控制设置。这项研究旨在创建下一代聚合物挤出模具，可以生产更广泛的各种更复杂的塑料部件。具体来说，这项工作旨在使聚合物挤出能够取代一类塑料零件的注塑成型，从而同时降低生产成本和制造时间。此外，它还致力于为设计师提供灵活性，以便使用具有不同横截面形状的全新塑料部件创建新颖的工程解决方案。开发的设计工具将有更广泛的应用，以创造其他可变几何结构，如变形飞机机翼和微型挤压模具。

This grant provides funding to develop variable-geometry dies for extruding complex plastic parts. Unlike most existing polymer extrusion dies, which have a single fixed geometry, design techniques will be created to build novel moving dies that morph between different shapes. Coordination of multiple actuators during the extrusion process will impose these changes in shape. The actuator locations will be optimized to provide the mechanical advantage required to resist the sizable pressure loads inside the extruder. The optimization will be accomplished with a genetic algorithm that considers the many design constraints, which include avoiding interference of moving parts, eliminating obstructions to the flow of the molten plastic, achieving a reasonably sized die, and minimizing actuator power consumption. Experimental work will develop new ways to manage the leakage of molten plastic within the die due to its moving parts. Prototype variable-geometry dies will be built and tested on a production extruder operated by an industrial collaborator. Validation experiments will derive empirical relationships between changes in the die geometry, extruder screw speed, and plastic temperature to provide process control settings that yield defect-free parts.This research seeks to create the next generation of polymer extrusion dies that can produce a wider variety of more complex plastic parts. Specifically, the work aims to enable polymer extrusion to replace injection molding for a class of plastic parts, thereby simultaneously reducing production costs and manufacturing time. Additionally, it aspires to offer designers the flexibility to create novel engineering solutions with entirely new plastic parts of varying cross sectional shape. The developed design tools will have broader application to creating other variable-geometry structures such as morphing aircraft wings and micro-scale extrusion dies.