Products + Processes
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Body Made of CFK
Volvo manufactures most of the body parts of the Polestar 1 electric car model using carbon fiber-reinforced plastic (CFRP), including engine hood, trunk lid, side panels, doors and the entire roof structure. Compared to the use of conventional materials, 230 kg can be saved in this way. The so-called spirit level, which improves the torsional stiffness between the underbody and the rear, is also made of CFRP. Volvo expects this to provide very good driving dynamics. The roof construction should not only become thinner and more stable than a steel pendant through the use of CFRP, but also enable a significantly lower roof line. The entire length and width of the roof is also covered by a glass surface that is only interrupted by a few body elements. The production center for the model, which is currently under construction, will be set up specifically to meet the needs of lightweight materials. The company plans to start series production in mid-2019.
Milling Cutters for Composite Materials
Hufschmied Zerspanungssysteme has developed a milling cutter that is intended to reduce the costs of machining fiber composite workpieces by up to 40 %. According to the company, the reason for this is the special coordination of cutting edge geometries and diamond coating. This means that carbon and glass fiber-reinforced materials can be machined in a single process step without fraying, delamination and without changing tools for roughing and finishing. Particularly in demanding material combinations with copper mesh, such as the CFRP-M21E material from the aerospace industry, time and cost-intensive reworking processes can thus be dispensed with. The Hexacut Eco milling cutter has chip- breaking cutting edge geometries, which can be used to reduce the cutting pressure. At the same time, the newly developed diamond coating DIP6p protects the milling cutter from aggressive wear mechanisms during the machining of abrasive and inhomogeneous composite fiber materials. It also makes the tool resistant to chemical influences and prevents the resins from the composite material from adhering to the milling cutter. According to Hufschmied Zerspanungssysteme, the geometry and coating of the new generation of cutters also reduces the component vibration of larger components, which makes machining increasingly difficult, especially in the aerospace sector.
Laser Zentrum Hannover
Welding Process for Multi-material Bodies
The Laser Zentrum Hannover (LZH) has developed a laser beam welding process for two- and three-sheet metal connections. This allows the joining of steel and aluminum at a speed of up to 7 m/min. According to LZH, one of the challenges in welding these alloys is the formation of hard and brittle intermetallic phases in the weld. Laser beam welding introduces heat into the workpiece selectively and only to a limited extent, which is why these phases are only formed to a limited extent. The basis for the remote laser beam welding process is the 3-D scanner optics developed by Trumpf Laser, which enables complex three- dimensional seam geometries even with large structures. According to the LZH, the compound achieves a shear tensile strength of approximately 67 % of the aluminum alloy. Due to the parallel arrangement of three welding seams, this can even be increased to about 95 %. The process was developed for battery housings of electric cars, seat structures and body components. According to LZH, this makes the process particularly interesting for body construction and can replace complex robot movements. LZH, Volkswagen, Inpro, Precitec, Matfem, Lunovu, Scherdel Marienberg, Infratec, Brandenburg Technical University Cottbus- Senftenberg and Fraunhofer IWS worked together in the joint project LaserLeichter funded by the German Federal Ministry of Education and Research under the coordination of Bosch. Associated partners were Trumpf, Astor, Thyssenkrupp, Bond-Laminates and Hydro Extrusion.
Materialise and HCL Technologies
Platform for Hybrid Production Planned
Materialise, a provider of software and services for additive manufacturing, wants to develop a platform for hybrid production together with the IT service provider HCL Technologies. The aim is to combine the advantages of additive manufacturing and CNC machining. As part of the collaboration, Materialise’s additive manufacturing technology will be integrated into HCL’s Camworks software. The aim is to combine the freedom of design of additive manufacturing with the speed and accuracy of CNC machining in the manufacture of metal parts. The partnership is the first initiative to create an integrated CAD/CAM solution for hybrid production in the Solidworks environment. According to Materialise, the new technology is expected to be available this year.
Light-controlled Curing of Epoxy Resin
The TU Vienna has developed and patented an epoxy resin that cures under the influence of light. The research group of Prof. Robert Liska at the Institute of Applied Synthesis Chemistry has investigated additives that can be added to ordinary epoxy resin. This allows the time of curing to be initiated specifically, since chemical reactions can be triggered by a bright flash of visible light, for example. At the point where the light hits the resin, a heat-releasing reaction starts, which spreads over the entire mass. According to the institute, this self-curing can also take place under water, which allows the resin to be used as a special adhesive. The self-curing epoxy resin can also be used in combination with carbon fibers or carbon fiber mats. According to the institute, it is therefore suitable for fiber-reinforced composites in aircraft, car and shipbuilding.
Fully Automated Wet-pressing Plant
To mark its anniversary, Krauss Maffei presented a fully automated wet-pressing system that halves cycle times and increases process reliability compared to manual processes. The plant is the company’s latest development in the wet-pressing process for the production of fiber-reinforced plastic components, which the company claims it has already brought to market in 2013. The wet-pressing plant presented produces test plates from basalt fibers. A robot equipped with needle grippers removes the fiber mats and feeds them to the application table, where a handling robot with mixing head (MK 10-2K-RTM) and wide slot nozzle applies the PUR matrix. The gripper robot places the mat in the mold before the forming and curing process begins. The carrier used with 8000 kN clamping force has corresponding interfaces for dosing machines so that epoxy resin, polyurethanes or polyamides can be processed as desired.
Screw for Foamed Thermoplastics
Ejot has developed a new connector for microcellular foamed thermoplastics. The special thread contour of the so-called Cell PT screw is characterized by specially shaped thread tips in conjunction with a sophisticated flank angle/radius combination in the thread area. The contour developed in comprehensive test series especially for cellular foamed thermoplastics enables, in contrast to self-curving geometries, material-protecting thread embossing through elastic-plastic forming in the plastic tube. Thread embossing deforms the compact surface layer in the core hole of the thread tooth and does not destroy it; it thus remains intact. The resulting high torque and force transmission in foamed thermoplastics guarantees maximum joining reliability, according to the company. In the case of blind hole connections, a further increase in torque is also achieved, as the specially shaped tip additionally penetrates into the plastic material at the bottom of the blind hole.
Laser Joining and Forming of Additively Manufactured Components
As part of the BMBF joint project “LightFlex” the Institute of Plastics Processing (IKV) at RWTH Aachen University is developing a photonics-based manufacturing process for components made of Fiber- Reinforced Plastic (FRP). The core of the new manufacturing process is the combined joining and forming process of a functional structure made of polyamide with fiber-reinforced thermoplastics (TP-FVK). According to the IKV, this process makes it possible for the first time to produce individual fiber-reinforced components economically, even in small series. While the thermoplastic FRP component, for example an organo sheet, is heated in an infrared emitter field, the near- surface heating of the additive manufactured structures takes place with the aid of a 1 kW laser from Laserline. Thanks to the combination of the laser with a 3-D laser scanning head provided by Arges, the focus of the laser can be shifted inline in all directions. According to the institute, this ensures that a defined near-surface melting also takes place with uneven and complex geometries.
Eloxalwerk Ludwigsburg and Fraunhofer ILT
Wear and Corrosion Protection for Magnesium
The Eloxalwerk Ludwigsburg (ELB) and the Fraunhofer ILT have developed a process with which components made of magnesium and other metals can be specifically protected against corrosion and wear. The materials scientists apply the high-performance plastic polyetheretherketone (PEEK) to the surface. To provide a component with the protective layer, it is first applied to the component together with additives by means of a precision application. Subsequently, a two- beam laser system ensures that the PEEK is specifically melted on the treated area. The result is a very thin high-performance polymer surface which protects the material against corrosion and abrasion. Initial tests have shown that the applied layer enables a 100 times longer service life of the component in the event of wear due to abrasion. The developers see possible areas of application for the new coating technology where temperature resistance or low friction and thus low wear are required, for example in moving parts of motors, gears or bearings.