The first time, continuous fiber reinforced thermoset material 3D printing

Continuous fiber reinforced composite material is a main material of the current domestic and spacecraft structures, having a low density and strength advantages. However, the conventional manufacturing process is complicated, costly, the use of 3D printing to produce continuous carbon fiber reinforced composite material more flexible design can be achieved, while helping to save time and resources, thus causing a lot of attention. May 5, China\’s first time in the world in space 3D printing continuous fiber reinforced composite material, is expected to achieve in-orbit construction of the station. 3D printing conventional continuous fiber reinforced composite material is a thermoplastic polymer material plurality compared to thermoplastic materials, thermoset materials have better mechanical properties, heat resistance, solvent resistance and the like, so 3D printing continuous fiber-reinforced thermoset materials It is expected to achieve more excellent mechanical properties and thermal properties. Recently, the University of Delaware Kun (Kelvin) Fu , who developed a 3D printing technology a dynamic capillary-driven , referred to in the face of local aid heating 3D printing (LITA), to achieve print continuous carbon fiber reinforced thermoset composite materials, fiber volume fraction in the printed material was 58.6%, the mechanical strength and modulus can reach to 810MPa and 108GPa . Work related to \”Dynamic Capillary-Driven Additive Manufacturing of Continuous Carbon Fiber Composite\” in the title, recently published \” Matter \” on.

[Photo explained]

LITA technology is based on the continuous wicking of the liquid resin between carbon fibers, the specific process is: a heater for drying the carbon fiber is locally heated, is formed along the fiber direction gradient temperature profile, so that the liquid thermosetting resin having a reduced viscosity from low to high temperature zone on the fiber, it will decrease the viscosity due to capillary forces between the carbon fibers adjacent to the inflow, while the higher temperatures that the liquid resin cures , rapid and synchronized infusion and curing, and the cured composite is an arbitrary 3D shape. Compared to a conventional heating atmosphere, this method may be faster local heating of the solid printed materialVelocity and higher extent of cure. 首次实现连续纤维增强热固性材料的3D打印 Researchers selected heating speed, temperature resistance, small contact area of ​​the carbon nanotube resistance joule heater, provide a controlled and stable heating source for the carbon fibers. Based on this, the liquid polymer researchers studied in detail and the cured filling between the fibers found in the liquid resin is injected carbon fiber situ rapid cure. Liquid resin by capillary action even against gravity, moves vertically upward through the carbon fibers. Since the liquid resin in the composite material the capillary action between the fibers and densification in order to achieve a higher fiber volume fraction, help to improve the material properties.

首次实现连续纤维增强热固性材料的3D打印
FIG 2 capillary action drive the liquid resin infusion and curing process

Researchers integration processing liquid transport and heating functions of the print head, the LITA implemented based 3D printing. Print path by the automatic manipulator control, can be printed on a two-dimensional, three-dimensional substrate or free space. SEM pictures demonstrate printed material dense structure, voids and defects are not three-dimensional tomographic reconstruction result is also verified printing process where a void or other damage to the fiber does not appear, indicating that this method may well be prepared to print continuous fiber-reinforced structure thermoset composites. Highly ordered and closely aligned carbon fibers also impart excellent mechanical properties of composites, tensile strength and modulus of the material can reach to 810MPa and 108GPa. Comparison with existing literature, exhibits the highest tensile strength and optimum temperature.

首次实现连续纤维增强热固性材料的3D打印
FIG. 3 3D printer design and material properties

This technique may be printed to print complex geometries in a plane, can also print a conformal structure on the surface, or even printing can be achieved in free space. Compared to conventional composite printing mode, the printing technology in fiber length, the temperature of the polymer used, the print moldability, geometric complexity and versatility and many showed a clear advantage.

首次实现连续纤维增强热固性材料的3D打印
FIG. 4 illustrates a function to print and display parts

Summary

Researchers selected continuous industrial-grade and high-performance carbon fiber epoxy 3D printing resin achieve continuous fiber-reinforced thermosetting material, 3D printing technology developed easilyProcessing high-performance composite materials, it is expected to provide a fast, energy-efficient and large-scale 3D printing method, provided new opportunities for the design and manufacturing engineering structure and function of complex three-dimensional structure. Related links: https: //www.sciencedirect.com/science/article/pii/S2590238520301818#!

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