DEVELOPMENT OF THE DIRECT ROVING PLACEMENT TECHNOLOGY (DRP)

The Direct Roving Placement (DRP) technology is in development at the Institute of Composite Structures and Adaptive Systems of the German Aerospace Center (DLR). A fully functional robotic unit that is able to produce dry glass or carbon fiber preforms has been set up at the Center for Lightweight Production Technology (ZLP) in Stade. All relevant process and material parameters that have an influence on the mechanical properties of parts being built with the DRP technology, are investigated. The main advantages of this new fiber placement technology are low material costs and high productivity. The core of the technology, the end-effector, is able to process raw carbon fibers as well as glass fiber rovings. The biggest difference compared to other placement technologies is the integrated online binder application system. The binder system is used to keep the fiber rovings fixed in position, after they have been applied onto a three-dimensional tooling surface. In addition, the online application of a binder provides multiple options of individually tuning the mechanical properties of the preform or the final part

CoRe HeaT - A new heating method for faster fibre placement

CoRe HeaT, the Continuous Resistance Heating Technology, is an alternative to infrared, laser or hot gas heating systems. It can be used for continuous production processes like Automated Fibre Placement (AFP), Automated Tape Laying (ATL) or similar processes like filament winding or braiding. The technology is suitable for carbon fibre materials, heating them up with the Joule effect via their own resistance. Main advantages of the technology are the extremely high heating rates combined with very fast response times. This gives the opportunity to significantly increase the average lay up speed of fibre placement processes, leading to an increased productivity

CONTINUOUS RESISTANCE HEATING TECHNOLOGY FOR HIGH-SPEED CARBON FIBRE PLACEMENT PROCESSES

The Continuous Resistance Heating Technology (CoRe HeaT) is an alternative to state-of-the-art heating systems for carbon fibre placement processes. It allows rapid heating with minimal reaction times and thus offers the potential to increase productivity for suitable processes. A brief overview of the technology is given with a focus on the development of a temperature prediction model. First experiments show how to validate the model for new materials. The aim is to achieve optimized heat generation by implementing the model into the temperature controller

CoRe HeaT - brandheiße Faserlegetechnologie

Die Continuous Resistance Heating Technology (CoRe HeaT) ist eine Alternative zu Infrarot-, Heißgas- oder Laser-Heizvorrichtungen. Die am DLR in Stade in Entwicklung befindliche Technologie wird derzeit beim Automated Fibre Placement (AFP)- Verfahren getestet. Ein Anpassen auf ähnliche Prozesse wie beispielsweise Wickeln oder Flechten ist jedoch einfach möglich. Besondere Stärken des Verfahrens sind extrem hohe Heizraten und gute Regelbarkeit. Dies kommt besonders bei der Verarbeitung von bebinderten Trockenfasern oder thermoplastischen Prepregs zum Tragen, bei denen hohe Prozesstemperaturen erforderlich sind

Continuous Resistance Heating Technology - Risks and Opportunities of a Novel Heating Method

CoRe HeaT, the Continuous Resistance Heating Technology, is a novel heating method that can be used for carbon fibre placement processes such as the Automated Fibre Placement method, tape winding or alike. The paper gives a short overview of the technology and its main properties. The main disadvantage and risk of the technology is that it is not compatible with all common production materials. Only suitable carbon fibre materials can be heated using CoRe HeaT. While dry fibre tape material seems to be unproblematic, some prepreg tapes were found to be critical. Microscopic analysis and electrical resistance measurements seem to be an easy and fast method to determine whether a tape is suitable for continuous resistance heating or not. Aside from this risk, the technology offers the opportunity to increase productivity while reducing costs through high-speed heating and superior energy efficiency

Posterbeitrag: Lokale Binderaktivierung Posterbeitrag: Kombi-Preformgreifer

Um einzelne Lagen miteinander zu verbinden, werden die Kohlenstofffaserhalbzeuge zwischen zwei Elektroden komprimiert. Der Widerstand des Aufbaus lässt sich auf diese Weise gezielt beeinflussen. Durch das Anlegen einer Spannung an die Elektroden erfolgt ein Stromfluss in Dickenrichtung

ELECTRICAL RESISTANCE HEATING – A METHOD FOR BINDER ACTIVATION IN CFRP PROCESSING?

The preforming of dry carbon fibers (CF) is a time- and money-consuming step in the production process of carbon fiber reinforced plastic (CFRP) parts. In this step, multiple CF layers are formed into a three-dimensional shape and need to be fixed to each other. Common fixing technologies are stitching or the use of binders. Most binders need to be activated thermally. Different technologies have been developed for that (chapter 1). This paper introduces a new method for activating the binder, which is presented in chapter 2. In order to find the most important process parameters for a fast, economical and energy-efficient process, the resistance behavior of different CF materials are investigated theoretically (chapter 3) and practically (chapter 4)