Another IACMI project involves Local Motors, which is experimenting with additive manufacturing for producing thermoplastic parts for vehicles.
One development that could speed adoption of thermoplastic automotive components is the opening of a scale-up manufacturing facility in Detroit, a joint venture by IACMI, Lightweight Innovations for Tomorrow (LIFT) and the University of Michigan. The facility will help companies working on thermoplastic composite projects move beyond small-scale test parts and produce full-scale parts for research and testing.
Meanwhile, engineers at DSM are doing their own experimenting, trying out various fibers and mixes of fibers for automotive industry thermoplastic materials with more eco-friendly flame retardants. They also are collaborating with an automotive manufacturer on thermoplastic parts that contain both DSM’s Dyneema® fiber, which has good ductility, and carbon fiber, which provides additional strength. The goal is to reduce the likelihood that pieces of a vehicle will fly off in crashes, which can happen with thermoset parts.
Keestra believes that alternatively-fueled vehicles could open up another automotive market for thermoplastic composites. DSM leveraged its expertise with fuel tanks for outdoor power equipment to move into pressurized storage containers for compressed natural gas. The next step in that evolution could be supplying the tanks for hydrogen-powered vehicles. The thermoplastic materials used in CNG tanks aren’t very different than those required for hydrogen, but the industry will have to design tanks that can handle the 700 bars of working pressure required for hydrogen versus the 200 to 250 bars that CNG tanks need.
Thermoplastic composites have many roles to play in the manufacture of all types of parts for lightweight conventionally-powered vehicles, in electric and/or hybrid electric/hydrogen fuel cell vehicles and perhaps even in autonomous vehicles, says Keestra. The added weight of sensors and cabling that is now going into vehicles will make it imperative for automakers to reduce weight in other areas wherever possible. “Light weighting cameras, cables and connectors really does make sense,” he adds.
Toughness for Aerospace
Aerospace manufacturers were early adopters of LFRT technology. Today, the most typical thermoplastic composition in the industry is PEEK (polyetheretherketone) or PEI (polyetherimide) with carbon, which can be woven fabric or unidirectional fibers, according to Wessner.
Offringa says that GKN Aerospace Fokker produces an array of thermoplastic composite products for aircraft, including floor panels, rudders and elevators for various Gulfstream jets, avionic housing parts for Boeing Apache helicopters and horizontal tails for Leonardo helicopters.
The material has two distinct characteristics that make it attractive for aerospace. “Thermoplastic polymers can be molten and then reshaped repeatedly. This makes processes such as stamp forming of ribs out of blanks and welding of assemblies possible,” says Offringa. Thermoplastics also provide a high level of material toughness, which translates into lower-weight structures with improved damage tolerance. This is of particular importance for thin-gauge structures such as aircraft control surfaces and fuselages.