At a Glance
Researchers at Colorado State have developed a novel technique for digital manufacturing of thermoset polymers, nanocomposites, and fiber-reinforced polymer composite (FRPC) materials which polymerize instantaneously above a certain temperature. The 3D printing technique enables simultaneous printing and curing of thermoset composites, eliminating the need for support structures, with minimal energy input at high production rates.
Fiber-reinforced polymer composites offer low density, excellent stiffness and strength, good thermal stability and chemical resistance. As a result, they are used in many sectors including aerospace, space, automotive, sport, wind energy, and biomedical. However, the manufacture of composites is expensive due to long cure cycles, expensive resources, high energy consumption, and labor. Mold design and fabrication is another drawback which slows down the manufacturing process.
3D printing can address all these issues and enable affordable manufacturing of composite materials and expand their application. For example, they can be used to manufacture complex parts of automobiles and aircrafts, biomedical prosthetics, and small wind turbine blades. However, 3D printing of composites with thermoset polymers and thermal curing has not been well developed.
Conventional manufacture of high-performance thermosets and composites requires the resin to be cured at elevated temperatures (~180 °C) for several hours in large ovens and autoclaves that scales in size with the part. In addition, manufacture of parts with complex geometries requires design and fabrication of complex molds and tooling. The conventional approach is slow and labor-intensive, requires a large amount of energy, and involves significant capital investment. The new technique developed for simultaneous printing and curing of thermoset polymers and their composites, eliminates the need for ovens and autoclaves, mold design and fabrication, long cure cycles, manual labor, and excessive external energy.
The approach utilizes newly developed resin systems that do not polymerize at room temperature but instantaneously polymerize and solidify at elevated temperatures in response to a local heat source. The resin, with or without reinforcements, is extruded from the nozzle of a printing robot and heated immediately using a local stimulus that controllably generates heat. The resin then polymerizes instantaneously as a result of a local rise in temperature, and thereby captures the desired print geometry.
- Printing process is fast (2 m/min)
- Can produce composites with a high-volume fraction of reinforcements (as high as 50% by volume)
- Requires minimal energy and power input (2W)
- Enables freeform printing (that eliminates the need for supports)
- Manufacture of complex parts in various industries:
- Biomedical (e.g. prosthetics)
- Wind energy (e.g. turbine blades)
- Repair of existing components
- Design of tooling/molds on which composites are placed and manufactures
Last updated: July 2020