Material supplier Hexcel Corporation views 3D printing as the next frontier in composites manufacturing. While it is not applicable to all composite applications, it provides a quick-to-market alternative for many smaller parts with intricate geometries. The company manufactures carbon fibers that are suitable for 3D printing and utilizes 3D printing primarily for aerospace parts production.
The carbon fibers Hexcel uses for 3D printing are not treated with sizing agents, which can interfere in the bonding of thermoplastics and carbon fiber. “Our unsized carbon fibers, HexTow™, ensure there are no adverse effects between the fiber and resin chemistry and provide excellent interfacial bonding properties with thermoplastic matrices for 3D printed parts,” says LaRhea McBee, carbon fiber technical support engineer with Hexcel.
In addition to supplying materials, Hexcel manufactures CFRP parts for customers, so moving into additive manufacturing was a logical step. Earlier this year, Hexcel entered a strategic alliance with specialty chemical supplier Arkema to develop advanced thermoplastics for aerospace applications. In 2017, Hexcel acquired an additive manufacturing technology, now called HexAM™, for aerospace and defense applications. HexAM uses a selective laser sintering (SLS) method of printing, which differs from continuous filament printing and is flight-qualified on several aerospace applications.
Based in Hexcel’s Hartford, Conn., facility, HexAM’s additive manufacturing technology combines milled HexTow carbon fiber with a high-performance PEKK thermoplastic in a powder bed system. It’s well-suited to making complex and organic geometries without the need for forging or welding, according to the company. HexPEKK parts are printed layer-by-layer using SLS to produce flight-ready, fully functional CFRP components. The parts offer significant weight, cost and time-to-market reduction compared to incumbent metal or composite technologies while still providing validated and repeatable engineering material properties, according to the company.
The four developments highlighted take different approaches to advancing the production, conversion and usability of carbon fiber. However, these projects – and numerous others throughout the industry – are all good indicators of the high level of interest in finding faster, more affordable and higher volume CFRP processes and production methods. The intensity and speed of development makes it inevitable that new techniques – even proprietary ones that companies try to keep close to the vest – will ultimately help advance the use of CFRP across all market segments.