By adopting a new approach KraussMaffei Reaction Process Machinery strives for a whole new level of performance in pultrusion, the continuous molding process for the manufacture of high-filled fiber-reinforced plastic components. A new efficient system solution lies at the heart of the development: the new iPul pultrusion machine. KraussMaffei presents the initial results at JEC World in Paris (March 14 to 16, 2017, Pavilion 6, Booth B 38) using the example of select applications in the wind energy and construction industries. Partners for the projects include Covestro (polyurethane), Evonik and Huntsman (both epoxy), as well as Thomas GmbH + Co. Technik + Innovation KG (Thomas Technik).
Unique combination
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The new pultrusion machines from KraussMaffei combine the direct injection of the matrix material and the radius pultrusion process in a unique way. "The direct injection of the matrix material using a metering machine and an injection chamber offers clear technical and economic advantages compared with the typical market practice where impregnation is generally effected by pulling the reinforcement through a bath", states Josef Renkl, Head of Pultrusion Development at KraussMaffei. The machine is more compact, the production speeds are higher. "To date the speeds are generally 0.5 to 1.5 m/minute. With the new KraussMaffei iPul machines we are aiming for decisively higher production speeds with more than 3 m/minute. This opens up completely new markets for pultrusion. In addition, the machines are able to manufacture not only straight but also curved profiles in the radius pultrusion process", adds Renkl.
An important component of the new machine is the metering technology which has been optimized especially for the pultrusion process. It injects the matrix material directly and continuously into the injection chamber. This means the matrix systems can work with a higher reactivity, which in turn can be specifically coordinated to the property patterns of the end product. Another advantage: The current open resin bath where impregnation of the dry fibers must take place with the use of additional guide panels is omitted. Furthermore, the injection chamber supports the higher speeds required in production and is much more flexible and precise. For instance, the injection points can be easily and individually set and adjusted specific to the product.
Following the injection chamber the impregnated fibers are pulled through a heated stationary die. The component is cured in several individually selectable heating zones to achieve the desired hardened state. A profile pulling unit transports the pultruded profile continuously through the machine at constant speed before it can be cut and assembled. All machine components can be operated centrally via a control system.
High flexibility with the matrix materials
Another advantage of the new iPul pultrusion machines from KraussMaffei is their flexibility. They are suitable for processing diverse matrix materials such as epoxy, polyurethane or in the future also polyamide 6. Fibers made from glass, carbon, basalt, or aramid are mainly used as reinforcement fibers. It is also possible to directly work in additives such as mineral fillers, pigments or flame retardants. With the new iPul pultrusion machines both linear profiles with complex cross-sections, as well as 2D and 3D curved profiles, can be manufactured in the patented radius pultrusion process. KraussMaffei is working closely with Thomas Technik, the inventor of radius pultrusion and an experienced supplier of pultrusion machines, which complement the metering machines from KraussMaffei perfectly.
Perfect for wind energy and construction
Pultruded profiles are characterized by their high fiber volume content and thus a high strength with low weight, making them suitable for use in the construction and wind power industries. Using the example of three select applications and in cooperation with partners from the chemicals industry, KraussMaffei demonstrates the feasibility and advantages of the new pultrusion machine. Polyurethane-based profiles for example for large-format windows with simultaneously narrow frames are the topic of the collaboration with Covestro. "Pultruded polyurethane profiles offer significantly better mechanical characteristics here than PVC profiles. The insulation properties are excellent, their production is cost-effective, mainly in comparison to common aluminum profiles. We see a huge future market here, particularly in public buildings, offices or other institutions", adds Wolfgang Hinz, Business Development Pultrusion at KraussMaffei. The second application example also comes from the construction industry. Partner for the concrete project with epoxy resins and glass fibers is Evonik. The third application stems from the wind energy sector. Here it is about the production of pultruded reinforcement elements for particularly large-format rotor blades in wind turbines. "Together with our partner Huntsman, we are pushing the development of new epoxy materials and pultrusion equipment technology", states Hinz. The aim is to develop Epoxy resin systems for carbon pultruded parts that will meet the high volume production needs of the wind industry.
KraussMaffei Tech Day Pultrusion
KraussMaffei presents more exciting developments, as well as a live demonstration of a pultrusion machine, on the technology day on June 28, 2017 in Munich.
