Dielectric Barrier Discharge Applicator for Heating Carbon Nanotube-Loaded Interfaces and Enhancing 3D-Printed Bond Strength

Abstract

Material extrusion (ME) 3D printing is a revolutionary technique for manufacturing thermoplastic parts; however, the printed parts typically suffer from poor interlayer bonding, which causes weak tensile strength in the build direction. Many methods have been proposed to address the mechanical deficiencies of 3D-printed parts, but most fall short of a production-ready solution. Here we report the use of a dielectric barrier discharge (DBD) plasma electrode mounted concentrically around the nozzle of an ME 3D printer for in situ welding of thermoplastic parts. This is the first report of a DBD being used as a non-contact means to induce Joule heating in resistive composite materials. The polymer welding process is accomplished by coupling the DBD with the carbon nanotube-loaded interfaces between the 3D-printed layers. The current passing through the part results in rapid resistive heating of the nanotubes and thermal welding of the interfaces. We show that parts printed with this method have isotropic strength and are equivalent to their injection-molded counterparts.

Radio frequency heating and material processing using carbon susceptors

“…[59][60][61][62] Some of these concepts have seen translation from academic labs to industry. 5 RF heating has demonstrated potential for rapid manufacturing applications for heating bulk materials or targeted parts of the specimens through volumetric or targeted heating. 22,24,25 Major questions surrounding this phenomena remain open.…”

“…2 In recent years, methods of advanced manufacturing that require rapid heating or targeted heating of components have been developed. 3 These include Joule or resistive heating, [4][5][6][7] induction heating, 8 vibrational heating, 9 ultrasonic heating and welding, 10 infrared heating, 11 and electromagnetic heating. 12,13 Specically, electromagnetic heating is a rapidly emerging eld that has several advantages including rapid, non-contact, non-invasive, and material-selective volumetric heating.…”

Rapid Manufacturing via Selective Radio‐Frequency Heating and Curing of Thermosetting Resins

“…Our group has previously shown that carbon nanomaterials heat up rapidly in response to RF fields. [5,7,[22][23][24][25][26][27] This phenomenon has already been utilized in manufacturing settings such as interlayer adhesion in 3D-printed thermoplastics, [5] bonding thermoplastic surfaces together, [26] curing preceramic polymer composites, [25] reduction of graphene oxide, [23] and processing of thermosetting prepregs. [27] Carbon nanotubes (CNTs) show excellent RF response, heating up rapidly, and reaching high temperatures easily.…”

“…[4] The ability to 3D print these multilayered structures would allow for the free-form fabrication of complex geometries, eliminating the additional cost of ovens and specific molds for each part. Additive manufacturing has been extensively used to 3D print thermoplastics [5][6][7] and metals. [8][9][10] A development of such an on-demand, rapid production technique could facilitate a distributed manufacturing economy for high-performance composites.…”

Digital Light Processing 3D Printing of Enhanced Polymers via Interlayer Welding

“…[6][7][8][9][10][11] Polymers are widely used in these 3D printing techniques, in which layer-by-layer deposition is always performed to create 3D polymer objects. [12][13][14] However, the layer-by-layer processing DOI: 10.1002/marc.202200053 results in weak interlayer bonding or adhesion between layers, [15][16][17][18] resulting in the anisotropic mechanical properties of the printed products.…”