Browsing by Subject "Process parameters"

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Investigating the effects of processing parameters in Reactive Extrusion Additive Manufacturing
(2023-04-21) Fogg, Michael John; Seepersad, Carolyn; Tehrani, Mehran
Reactive Extrusion additive manufacturing (REAM) is an AM method in which a liquid thermoset feedstock is deposited and cured in-situ. Thermosetting resin is mixed with a catalyst and extruded, rapidly initiating an exothermic curing reaction which crosslinks the polymer chains. The robotic REAM system utilized in this work couples this material extrusion system to a 6 degree-of-freedom robotic arm for actuation, and utilizes path-planning software which converts g-code into robotic trajectories. The REAM process has many unique advantages such as the ability to fabricate parts with isotropic material 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 which 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 in order to resolve complex features and produce 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 amount of time between layers are investigated, and their effect on resulting part properties are characterized. Additionally, the ability to fabricate unsupported overhangs, and bridge gaps as a function of different processing parameters is also studied. By understanding these variables and their effects, the system can be tuned to improve accuracy, repeatability, and feature resolution.