Victrex Uni-Directional Tape Helps Electroimpact Improve Thermoset Layup Speeds

Factory automation and tooling specialist Electroimpact Inc. has advanced the production of large structural components from thermoplastic composites for aerospace applications through enhanced automated fiber placement (AFP) processing technology. It notably was able to increase laydown speeds of thermoplastic uni-directional tape (UDT) to 4000 inches per minute. Electroimpact worked with Victrex, a supplier of high-performance polymers, to leverage the unique properties of its thermoplastic composite prepreg tape, AE 250 LMPAEK UDT.

Large composite structures in aerospace, such as the wings and fuselage, currently are almost all thermoset based. Thermoset composites can be challenging, however, because they require lengthy curing in an autoclave large enough to hold the structure. The autoclave is a production bottleneck and requires a considerable amount of energy to operate.

Sustainability is important for the aerospace industry, and OEMs and tier suppliers are looking not only to improve the fuel efficiency of aircraft but also to introduce efficiencies throughout the supply chain. Thermoplastic composites offer substantial benefits, which has led to their increasing adoption in the manufacture of smaller parts. Moreover, thermoplastic composites can be processed out of autoclave, so manufacturing processes have been developed to take advantage of their potential for high-speed production. Recyclability of thermoplastic composites is a major advantage, as well, said Victrex.

“The significance of processing thermoplastic UDT at 4000 inches-per-minute layup speeds with the variable spot size laser is, for the first time that we know of, that thermoplastics are able to achieve thermoset layup speeds,” explained Michael Assadi, Chief Engineer at Electroimpact. “These developments can help eliminate the need for autoclave cure, and offer new throughput advantages for thermoplastics.”

Electroimpact has enhanced its existing AFP processing technology through the deployment of a new laser heating system, which has the potential to revolutionize thermal processing for the aerospace industry. “We are really excited to offer this new laser technology and using the high-performing LMPAEK composite material from Victrex on a broader scale to meet previously unmet customer needs. I’m convinced that based on ongoing in-depth support from Victrex at every stage of the project, high-speed production and high performance of the advanced Victrex AE 250 UDT will enable the production of large-scale aerospace structural components in the years to come,” Assadi added.

Victrex AE 250 UDT is a novel, high-performance thermoplastic composite prepreg tape that was designed by Victrex to have mechanical, physical, and chemical resistance properties typical of the PAEK polymer family, such as PEEK, but with a 40^oC (104^oF) lower crystalline melting temperature, at only 350^oC (582^oF).

Electroimpact has already gone one step further and trialed in-situ production with Victrex AE 250 UDT. A test program comparing several different materials demonstrated that the Victrex LMPAEK UDT delivered the best performance producing porosity-free laminations, including the most dimensionally uniform and even distribution of fiber in the resin. As a result, a high-quality component can be produced without any additional processing steps after layup, eliminating the need for over consolidation. In-situ manufacturing has long been the holy grail for aerospace composite structures, said Victrex.