“Developing a new polymer is a big investment, and polymer manufacturers don’t usually undertake such an action before they see market potential,” says Wijskamp. “You also see it with machine builders. Ten to 15 years ago there were only some very dedicated, small companies building machines for thermoplastic composite processing. Now you see all major machine builders going into this market.”
Ongoing Research to Encourage Adoption
While thermoplastic composites offer many benefits and have come a long way in the past decade, there’s still work to be done to advance mainstream use. TPRC has been a leader in Europe’s thermoplastic composite research. Consortium members share what TPRC researchers discover in a pre-competitive environment and apply it to their own manufacturing processes.
Ongoing research at TPRC includes many aspects of thermoplastic composite production, including stamping and overmolding, fusion of thermoplastic parts and long-term performance. Researchers develop software modeling tools that can help characterize the materials, fine-tune processes and improve tool production.
Sustainability is a major focus at TPRC. As the use of thermoplastic composites increases, the industry must be prepared with solutions for production scrap and for the recycling of end-of-life products, Wijskamp says. For one project, TPRC supported GKN Aerospace in the production of compression-molded access panels manufactured from recycled thermoplastic waste material. The panels were installed and tested in Bell Helicopter’s V-280 Valor.
End Users Seek an Array of Properties
As thermoplastic composite manufacturers turn their attention to bringing larger parts to market, equipment manufacturers like Coriolis Composites are feeling the impact. In the past, the company has only built high-performance AFP machines that use ¼-inch wide tapes for the production of small, intricate thermoplastic parts. Now customers want something different. Coriolis is being asked to design and build wing and fuselage machines that use wider tapes to speed up the thermoplastic composite manufacturing process, according to Burak Uzman, the company’s general manager.
There is a tradeoff for that speed, however. Wider tapes are less steerable and do not afford the same flexibility for design optimization as narrower tapes do, Uzman says. Designing for wider tapes foregoes opportunities to have a lighter weight structure.
In addition to a move toward wider tapes, Uzman currently sees a lot of interest in in-situ consolidation of thermoplastic composite components. The challenge there is ensuring the material forms strong bonds between layers. “In thermosets we take the bond between the different layers for granted, because thermosets spend hours in the autoclave and you put the pressure on them. That gives the resin chemistry plenty of time to form those linkages,” he says. But with in-situ consolidated thermoplastic composites, getting the required interlaminate properties depends on how the AFP machine processes the laminate, and, even more important, how well the engineers that program the machine understand the processing parameters like resin chemistry.