Researchers Yongsan An and Woon-Ryeol Yu explore the improvement of 3D printing by studying alternative materials. In the recently published "3D Printing of Continuous Carbon Fiber Reinforced Shape Memory Polymer Composites", the challenges of mechanical properties that plague many industrial users are discussed . In this article, let's take a look at how researchers are using composites to improve the mechanical properties of 3D printing.
In this study, the researchers tried continuous carbon fiber-reinforced shape memory polymer composites (SMPCs), thermoplastics and thermosets, in FDM 3D printing.
Researchers tested the parameters and printed samples to learn more about the advantages and limitations of smart materials such as SMP—the ability to change with the environment and then return to normal shape. This type of material is similar to 4D materials, allowing users to gain greater flexibility in various applications. The research team hopes to improve the manufacturing process with the addition of carbon composites.
The research team created a custom FDM 3D printer for the study to make continuous fiber reinforced SMPC parts. In terms of materials, two different types were selected for evaluation: PLA and polyurethane-type SMP filaments (as a thermoplastic matrix) and SMP epoxy resins as a thermoset matrix. The team then added continuous carbon fibers to the filaments for reinforcement.
When they printed out the samples to be tested, they tested the differences in temperature and printing speed, and then the team evaluated the mechanical and shape memory characteristics.
The researchers wrote in the article that "the storage modulus (G '), the loss modulus (G"), and the viscosity of PLA decrease near its melting point. The storage modulus decreases at a greater rate than the loss modulus, giving PLA more liquid properties. Therefore, PLA can be easily extruded from a nozzle having a temperature of 180 ° C. "
"The PLA filaments without CF are smoothly extruded from the nozzle, regardless of whether the diameter is greater than the fusion area. However, for nozzles with a diameter of 1.5 mm, the PLA matrix is extruded as if spirally wound CF. This is because PLA is more extruded than CF because CF is not stretched during the extrusion process. In addition, poor temperature and different extrusion speeds cause CF to fail during 3D printing. On the other hand, for 2 mm diameter Nozzles, PLA and CF are directly extruded due to their synchronized extrusion speed.
There are many challenges, such as the CF is not fully coated with PLA. To better optimize PLA and CF supply rates, as well as material structure and fusion time, the researchers created an improved print head. They also added calendar rolls and appropriate tensioning devices.
The researchers said that compared to traditional 3D printed polymers, the printed SMPC showed better mechanical properties in the fiber direction.
The strength and stability of mechanical properties is an ongoing challenge in 3D printing, but as researchers are determined to improve materials and processes from carbon lattices to titanium and progressive manufacturing techniques to check biocompatibility There is room for continuous improvement.