Low‐pressure additive manufacturing of continuous fiber‐reinforced polymer composites

Abstract

Continuous fiber-reinforced polymer composites have found a wide range of applications in the automotive and aerospace industry due to their lightweight properties. Recently the use of additive manufacturing (AM) has been developed for the fabrication of these composites. This study investigates the use of both atmospheric and, for the first time, low-pressure (1 Pa) processing conditions for the AM of continuous carbon, glass, and Kevlar fiber-reinforced nylon composites. Differential scanning calorimetry was used to compare the thermal properties of the three types of fiberreinforced filament prior to printing. It was found that the melting peak was dependent on filament type, which can be related to the polymer processing conditions used during their fabrication. Based on computed tomography measurements, it was found that the use of low-pressure printing conditions yielded a reduction in porosity for the carbon, glass, and Kevlar printed composites of 5.7%, 1.0%, and 1.7%, respectively.The mechanical properties of the composites were compared, using a short beam shear test, which assisted in the measurement of interlaminar properties. An increase in interlaminar shear strength of 33%, 22%, and 12% was obtained for the carbon, glass, and Kevlar fiber-reinforced polymer composites, respectively, when printed under low pressure, compared with that obtained at atmospheric pressure. K E Y W O R D S3D printing, additive manufacturing, fiber-reinforced polymeric composite, low pressure, vacuum

3D Printing of Fibre-Reinforced Thermoplastic Composites Using Fused Filament Fabrication—A Review

“…Goh et al [ 41 ] observed that the overlapping of fibre bundles can reduce this porosity, however it could not be eliminated completely. The reduction in printed part porosity associated with the use of low pressure processing conditions during printing (1 Pa) has been successfully shown to increase the interlaminar shear strength (ILSS) of carbon, glass and Kevlar, by 33%, 22% and 12% respectively, compared to those materials printed under atmospheric pressure [ 53 ]. Another method of both decreasing the porosity of the FFF printed parts, as well as enhancing interlayer adhesion, is the use of atmospheric plasma surface activation treatments.…”

Failure analysis of 3D printed woven composite plates with holes under tensile and shear loading

“…The thermal properties of the "prepreg" carbon fibre filaments are evaluated using differential scanning calorimetry (DSC). The glass transition temperatures = 68 °C but the melting peak was found to be absent even the filaments was exposed to 250°C for 30 hours [23]. Previous authors have highlighted that the shape and size of the melting peaks observed in DSC are dependent on the thermal history of the nylon polymer [24].…”

Fused Filament Fabrication of Polymers and Continuous Fiber-Reinforced Polymer Composites: Advances in Structure Optimization and Health Monitoring

“…A melt pump and a pressure roller are also reported to apply mechanical consolidation after deposition. The reduction in printed part porosity associated with the use of low-pressure processing conditions during FFF printing has been reported to increase the interlaminar adhesion of various composite systems [ 114 , 115 ].…”