"We're making vehicles lighter. This will allow them to transport higher cargo loads while using less energy." This is the corporate philosophy of Carbon Truck &Trailer GmbH. A new iPul pultrusion system for lightweight construction profiles made of carbon fiber reinforced plastic (CFRP) is one of the major reasons behind the success of this company based in Stade, Germany. The newly installed pultrusion system, delivered by Pultrex (a British KraussMaffei subsidiary), produces profile parts for around 70,000 vehicle chassis annually.
KraussMaffei and Pultrex demonstrated their pioneering spirit – and not just by tailoring the system design to customer requirements. "Despite all the obstacles, we managed to deliver and commission the system on schedule," explains KraussMaffei Sales Expert Wolfgang Hinz. The unpredictable political situation in the wake of Brexit as well as the consequences and other limitations caused by COVID-19 were certainly not foreseeable when the system was ordered in mid-2020. "The experience and dedication of the technicians and project managers helped in commissioning the system according to plan," Hinz continues.
New location for increasing needs
Carbon Truck &Trailer GmbH (Carbon TT) is based in the "CFK (CFRP) Valley" in Stade / Lower Saxony. The young company specializes in building carbon-fiber-based chassis for lightweight commercial vehicles. Now the CFRP specialists have a new highly automated iPul pultrusion system up and running at their location in Buxtehude near Hamburg. The system was supplied by Pultrex, a KraussMaffei subsidiary. It produces large CFRP profiles in series, which are used in high-load components for vehicles such as buses, small trucks and mobile homes. "The new iPul system makes it possible for us to manufacture components in series at a consistently high level of quality. At the same time, the system gives us another selling point in multi-axial pultrusion – there are only five other systems like this one in the world," says Gerret Kalkoffen, Managing Director of Carbon TT.
Lower weight and higher payload
"Our carbon lightweight construction solutions help in meeting increasingly rigid requirements for sustainability, efficiency and safety. Especially for vehicles powered by batteries and hydrogen fuel cells, carbon fibers provide more material advantages than just their weight," explains Kalkoffen. A CFRP chassis is approximately 60% lighter than comparable steel chassis – this weight reduction lowers CO2 output and increases both the payload and the cruising range. In addition, the CFRP chassis compensates for the additional weight of batteries in electric vehicles and effectively protects them in the event of a crash.
The team of Carbon TT is proud of their new Pultrex iPul pultrusion system. On the left: Managing Director Gerret Kalkoffen
Pioneers among their own kind
"Our customers are automotive OEMs with high standards. Our own standards for the technology and service of our production systems are equally high," says Kalkoffen. "In Pultrex, we've found a partner with decades of experience in pultrusion. In collaboration with KraussMaffei, they offer fast and reliable service."
The innovative gripper concept of the Pultrex system made an especially positive impression. "The grippers operate with precision and without slipping. This is a 'must' for ensuring the consistently high quality of our complex CFRP profiles." And when you do business with Pultrex and KraussMaffei, all system components – both for mixing and metering technology and for injection and pultrusion technology – come from a single source. And when service is required, there is a central contact person.
Production at high speeds – just in time
Customers of Carbon TT set the pace for production with their order quantities and process requirements. This is where the iPul technology can unleash its full performance potential. Production can run at a speed of up to 2.25 m per minute at 20 tons of pulling force. For large and complex profiles, pultrusion can even be carried out at up to 40 tons in parallel operation.
For wrinkle-free reforming of multi-axial roving, CarbonTT developed its own roving guide, which is being used for the first time on the new system. The injection box makes it possible to quickly and flawlessly impregnate the exceptionally large profiles with thick walls and a high fiber volume fraction.
The fibers are soaked in the injection box with a polyurethane matrix and then shaped into the approximate final profile form. At the same time, the closed box prevents any unwelcome odors which arise during production with open baths.
The mold was adapted and designed by Carbon TT with spring-in and shrinkage taken into account for the final geometry. The profiles are trimmed down to the final dimensions automatically by the system and then processed further.