Freeform Additive Manufacturing of Carbon Fiber Reinforced Composites Using Dielectric Barrier Discharge-Assisted Joule Heating

In this work, a novel out-of-oven additive manufacturing (AM) technique to rapidly print and cure thermosetting carbon fiber reinforced composites (CFRCs) using dielectric barrier discharge (DBD)-assisted Joule heating was developed. Conventionally, CFRCs are produced by automated fiber placement machines (AFPs) that use large, cumbersome molds and time-consuming oven/autoclave treatments to cure CFRCs in the desired shapes. Recently, out-of-oven AM has garnered attention as a method to manufacture CFRCs without the use of molds. AM allows for on-the-fly printing and curing of thermosetting CFRCs; however, current out-of-oven AM techniques are limited to UV-curable, low viscosity, or rapid-curing resins. Here, the DBD was used for in-situ heating and curing during AM of continuous CFRCs; this method is resin-agnostic, applying to most commercially available thermosetting resins. As the partially cured composite (prepreg) is deposited, Joule heating induced via a DBD applicator allows the part to cure in the desired shape; this is possible because of the conductive carbon fiber susceptors inside the part. Composites manufactured by this method show properties similar to those manufactured in conventional ovens. With the help of this technique, one can print composites in free space or on stationary and mobile substrates. 2D structures, and 3D multilayered structures can be printed. Automation of this process is also demonstrated. This technology leverages the advantages of AM techniques to enable the printing of high-performance and lightweight materials in any desired shape.