A new additive manufacturing process to produce plastic-based composites using thermally activated materials

The significance of composites cannot be overstated in the manufacturing sector due to their unique properties and high strength-to-weight ratio. The use of thermoplastics for composites manufacturing is also gaining attention due to their availability, ease of operation, and affordability. However, the current methods for plastic-based composites are limited due to the requirements of long curing times and pre- and post-treatment, thereby resulting in longer lead times for the desired product. These methods also limit the freedom to operate with different forms of materials. This research presents a novel additive manufacturing process to produce high-quality plastic-based composites with bespoke properties for engineering applications. The process is referred to as Composite Plastic Manufacturing (CPM) and is based on the principle of two material extrusion additive manufacturing technologies, namely filament and syringe extrusion equipped with a heat chamber.

To establish the viability of the new process, various composites were manufactured and tested in accordance with British and International Standards. Polylactic Acid (PLA) and Acrylonitrile Butadiene Styrene (ABS), two popular and widely used thermoplastic materials, have been interlaced with various thermally activated materials (graphene-carbon hybrid paste, heat cure epoxy paste, and graphene epoxy paste) to produce plastic composites. The capabilities and effectiveness of the new process have been demonstrated through rigorous comparative experimental analysis such as mass, dimension, ultrasonic, tensile strength, microstructural, hardness, and flexural strength. The results have been compared with commercially available materials (PLA, Graphene-enhanced PLA, ABS), as well as with the literature, to demonstrate the superiority of the CPM process.

The parts manufactured by CPM showed superior mechanical properties compared to commercially available filament materials and parts made by other methods in literature. The increase is shown to be in the range of 1.7% to 43% for tensile strength, 16.9% to 30.7% for hardness and 5.8% to 41.7% for flexural strength, based on the product requirements. These requirements are dictated by the addition of layers of thermally activated materials that increase the mechanical properties of the composites made by CPM. The results demonstrate that the CPM process is capable of producing high-quality plastic composites and can be used to create products with customized properties. Furthermore, the composites manufactured by CPM have also shown strong bonding between the layers of polymer and thermally activated materials; thus, highlighting the effectiveness of the process.

The new additive manufacturing process is a less resource intensive method that provides a cost and time-effective option to the manufacturing industry to produce plastic-based composites with superior and bespoke mechanical properties compared to existing methods. CPM is a first of its kind integration of two different material extrusion additive manufacturing technologies (i.e., fused filament fabrication and syringe extrusion) in a desktop-based system. The process is capable to produce strong plastic-based composites using different polymer and thermally activated materials in a consistent a manner.