Investigating the effects of processing parameters in reactive extrusion additive manufacturing

Abstract

Reactive Extrusion additive manufacturing (REAM) is an additive manufacturing (AM) process in which a liquid thermoset feedstock is deposited and cured in situ. The REAM process has many unique advantages such as the ability to fabricate parts with isotropic mechanical properties, initiate curing without external energy input, and utilize high extrusion rates. However, there are many complex factors such as curing kinetics, feedstock rheology, and thermal gradients that can influence the capabilities of the REAM system and the resulting dimensional accuracy and mechanical properties of the fabricated parts. Understanding the processing parameters of an AM process is crucial to resolving complex features and producing high-quality parts repeatably. While REAM has been documented in the literature, no in-depth studies investigating these processing parameters exist. In this work parameters such as the extrusion rate, deposition speed, and the elapsed time between layers are investigated, and their effect on resulting part properties are characterized. Additionally, the ability to fabricate unsupported overhangs and bridges is also studied as a function of different processing parameters. By understanding these variables and their effects, the system can be tuned to improve accuracy, repeatability, and feature resolution.