Ohio, US: Carbon fibre-reinforced polymer composite parts that are capable of withstanding highest temperature has successfully been 3D printed by Air Force Research Laboratory (AFRL) researchers at the Wright-Patterson Air Force Base (WPAFB) near Dayton, Ohio in the United States.
This achievement comes as the Materials and Manufacturing Directorate at the AFRL, in a joint effort with the University of Louisville and NASA’s Glenn Research Centre, explores the possibilities of 3D printing high-temperature polymer for aerospace applications. The progress paves the way for a new generation of cost-effectiveness in meeting air force manufacturing demands.
According to Dr Hilmar Koerner, a scientist from the polymer matrix composite materials and processing research team who contributed to the development: ”These 3D printed parts can withstand temperatures greater than 300 deg C, making them potentially useful for turbine engine replacement parts or in hot areas around engine exhaust.”
Multiple benefits come with polymer matrix composites for the United States Air Force. These include their light weight and durability under high-temperature extreme conditions—two crucial properties as far as 3D printed parts for aircraft engines are involved. Such materials reduce fuel consumption and in turn, maximise aircraft range and operating costs.
Even in conventional manufacturing, high temperature materials are difficult and costly to produce. As they are typically used for military-specific functions, the supplier base is particularly limited. In this regard, such additively manufactured high-temperature polymer allows for greater accessibility and affordability in the industry.
The new carbon fibre-reinforced polymer contains thermoset resin—which has higher mechanical and physical strength than many thermoplastics—with added carbon fibre filaments. Most polymer composites are made of a fibre, then embedded in a resin made from epoxy—or a similar material. This creates a stronger material as embedded fibres tend to fortify the matrix.
Dr Koerner and the research team used selective laser sintering technology to experiment with high-temperature polymer resins. While polymers could be successfully 3D printed, the materials produced easily melted as they were removed from the powder bed for post-processing.
However, Dr Koerner suggested using carbon fibre as a filler to be included in the resin material, to facilitate better heat transfer from the laser to the matrix. This is due to the carbon fibre’s higher heat conductivity (compared to the polymer itself), hence heating up the mixture more quickly. This process enables better bond formation among the molecules in the material using the laser’s heat, without breaking down (melting) later.
It was after the carbon fibre reinforcement that the researchers were able to print samples with other configurations of high-temperature polymer composite.
Dr Jeffrey Baur, principal materials engineer at AFRL, commented that “high-temperature polymer composite parts that are small and have complex features will be extremely beneficial and advantageous not only for the Air Force, but have the potential to be a game-changer throughout industry.”
Currently, based on preliminary test results, more testing is needed for the material to be used on air force platforms.