Polymer matrix composites are extremely attractive to researchers working on next-generation applications due to their lightweight properties and ability to withstand extreme conditions in high-temperature environments. Typically, polymer composites consist of a fiber, such as glass, embedded in a matrix or resin made of epoxy or other material. The embedded fibers reinforce the matrix, making the resulting material stronger.
During a polymer additive manufacturing technique called laser sintering, a high-temperature laser is run across a bed of polymer powder to form a predesigned, computer-generated shape. This process is repeated multiple times with new layers of powder and laser energy until a 3D part is complete.
In conjunction with NASA's Glenn Research Center and the University of Louisville, researchers successfully printed the highest-temperature-capable, reinforced polymer composite parts using additive manufacturing. Consisting of a high-temperature thermoset resin infused with carbon fiber filaments, this material produces 3D-printed parts that can withstand temperatures greater than 300 °C, making them potentially useful for turbine engine replacement parts, or in hot areas around engine exhaust.
While experimenting with high-temperature polymer resins, researchers found that the polymers printed well, but when they removed the pieces from the powder bed for post-processing, the material would essentially melt, proving useless. To counteract this issue and better enable molecules to entangle and form a shape under the heat of the laser, carbon fiber filler was added to the resin material as a means of enabling better energy transfer from the laser to the matrix. The carbon fiber would cause the laser to heat the material much faster by absorbing the laser energy and conducting heat much faster than with the polymer alone.
The team successfully printed a number of test coupons and brackets with the material and plan to demonstrate the ability to print larger parts as the next step in the process. Preliminary test data indicates that the material can withstand elevated temperatures, but further testing and qualification of the material is needed.