Novel form-flexible handling and joining tool for automated preforming

The production rates of carbon fiber reinforced plastic (CFRP) parts are rising constantly which in turn drives research to bring a higher level of automation to the manufacturing processes of CFRP. Resin transfer molding (RTM), which is seen as a production method for high volumes, has been accelerated to a high degree. However, complex net-shape preforms are necessary for this process, which are widely manually manufactured. To face these challenges a new concept for the manufacturing of carbon fiber preforms with a form-flexible gripping, draping and joining end-effector is presented and discussed. Furthermore, this paper investigates the application of this concept, describes the initial build-up of a demonstrator, focusing on material selection and heating technology, and discusses test results with the prototype. This prototype already validates the feasibility of the proposed concept on the basis of a generic preform geometry. After a summary, this paper discusses future in-depth research concerning the concept and its application in more complex geometries. © 2015 by De Gruyter 2015

AUTOMATED MANUFACTURING OF LARGE, THREE-DIMENSIONAL CFRP PARTS FROM DRY TEXTILES

At present, the manufacturing of large parts from carbon fiber reinforced plastic in aerospace is mostly done by manual labor. One of the objectives of The Center of Lightweight Production Technology in Augsburg, Germany, is to transfer manual production methods into automated processes. This work addresses the process chain starting with dry textiles, via production integrated quality assurance, to a cured part. A gripper system is required to handle the pliable and delicate dry carbon fiber textiles in the preforming process. The project aims to develop such a system and establish an automated application. A final demonstration of the system’s capabilities allows evaluation of the current level of maturity and usability. Sensor technology is to be integrated into the production process for quality assurance purposes. The position and draping of cutpieces are determined by laser light section technique and fiber angle measurement. This allows detection of process parameters and potential deviations in the production chain. Corrections can be applied early, which offers a clear advantage over the current inspection of the finished component. Yet another focus is the enhancement of the setup for resin infusion. The application of a pretailored VAP membrane using a mechanized layup system allows for fast, robust and repeatable vacuum bagging with a significant reduction of manual labor. The presentation will give insight to the development of the gripper system, quality assurance measures, and semiautomated vacuum bagging including their current level of maturity

Integrated Gripping-system for Heating and Preforming of Thermoplastic Unidirectional Tape Laminates

Forming and overmolding of thermoplastic multi-layer UD-tape laminates has become increasingly important due to its potential for large-scale production. In the process the tape laminates have to be heated above melting temperature of the polymer in an infrared heater and then transported into the mold. To guarantee the formability of the laminate the temperature has to be maintained above the melting temperature during handling. To improve part quality a preforming of the tape laminate prior to overmolding is preferable. Integration of the preforming step in the handling process allows the shortening of the process route. In this work a gripping-system which allows further heating and preforming of the laminate during the handling process is presented. The temperature losses during transport have been modelled using the Stefan-Boltzmann law. By means of temperature measurements it is shown, that the integrated infrared-heaters allow a compensation of the cooling during handling, resulting in lower maximum heating temperature in the upstream infrared heating field and therefore a reduction of heating time and degradation of the polymer. The repeatability of the handling-integrated preforming has been evaluated using three-dimensional overlays of the resulting 3D-shaped laminates acquired by a laser scanning arm

Systematic gripper arrangement for a handling device in lightweight production processes

Handhabungsgeräte sind ein integraler Bestandteil automatisierter Produktionsprozesse. Dennoch werden sie in der Regel als nicht wertschöpfend angesehen, weshalb ihre Planung und Projektierung mit geringem Zeit- und Personalaufwand so effektiv wie möglich sein sollte. Gleichzeitig bleiben sie ein wichtiger Teil der Prozesskette und müssen in diesem Zusammenhang bestimmte Bedingungen erfüllen. Um ihre Funktionalität zu gewährleisten und wenig Zeit in die Projektierung zu investieren, sind Handhabungsgeräte oft überdimensioniert. Insbesondere bei flachen Teilen führt dies zu schweren Handhabungslösungen, bei denen das Gewicht des Handhabungsobjekts und des Handhabungsgerätes in einem Missverhältnis zueinander stehen. Ziel der vorliegenden Arbeit ist es, die Projektierung von Handhabungsgeräten so weit wie möglich zu automatisieren. Dieser Prozess wird am Beispiel der Prozesskette zur Herstellung von Leichtbauteilen mit den Verfahren „sheet molding compound“ (SMC) und „resin transfer molding“ (RTM) dargestellt. In einem ersten Schritt wird ein modulares Handhabungsgerät entwickelt und aufgebaut, das eine große Anzahl von Greiferanordnung ermöglicht. Mit diesem Handhabungsgerät kann dann die resultierende Durchbiegung von flachen Bauteilen mit verschiedenen Greiferanordnungen gemessen werden. Um sicherzustellen, dass es nicht immer notwendig ist die Durchbiegungen zu messen, wird mit ABAQUS ein Modell aufgebaut, das eine Simulation der Durchbiegung ermöglicht. Anhand dieses Simulationsmodells wird eine Designlogik für die Anordnung der Greifer entwickelt. Diese Designlogik arbeitet in zwei Schritten und basiert auf dem Ansatz des „growing neural gas“ (GNG), das durch die Implementierung zusätzlicher Regeln an das Problem angepasst wird. Zuerst wird eine erste Greiferkonfiguration basierend auf der Geometrie des Objekts erstellt, die dann durch einen iterativen Prozess aus Simulation und Anpassung verbessert wird. Da die Herstellung von Leichtbauteilen oft mehr als nur einen Zuschnitt erfordert, werden am Ende systematisch verschiedene Lösungen für die verschiedenen Zuschnitte zu einer Greiferanordnung zusammengefasst und ein Verfahren gezeigt, wie dies ,mit dem zuvor entwickelten modularen Handhabungsgerät realisiert, werden kann

Advances in Manufacturing Technology XXVII: Proceedings of the 11th International Conference on Manufacturing Research (ICMR2013)

ICMR2013 was organised by Cranfield University on the 19-20 September 2013. The conference focuses on any aspects of product development, manufacturing technology, manufacturing systems, information systems and digital technologies. It provides an excellent avenue for researchers to present state-of-the-art multidisciplinary manufacturing research and exchange ideas. In addition to the four keynote speeches from Airbus and Rolls-Royce and three invited presentations, there are 108 papers in these proceedings. These papers are split into 24 technical sessions. The International Conference on Manufacturing Research is a major event for academics and industrialists engaged in manufacturing research. Held annually in the UK since the late 1970s, the conference is renowned as a friendly and inclusive environment that brings together a broad community of researchers who share a common goal; developing and managing the technologies and operations that are key to sustaining the success of manufacturing businesses. For over two decades, ICMR has been the main manufacturing research conference organised in the UK, successfully bringing researchers, academics and industrialists together to share their knowledge and experiences. Initiated a National Conference by the Consortium of UK University Manufacturing Engineering Heads (COMEH), it became an International Conference in 2003. COMEH is an independent body established in 1978. Its main aim is to promote manufacturing engineering education, training and research. To achieve this, the Consortium maintains a close liaison with government bodies concerned with the training and continuing development of professional engineers, while responding to the appropriate consultative and discussion documents and other initiatives. COMEH is represented on the Engineering Professor’s council (EPC) and it organises and supports national manufacturing engineering education research conferences and symposia

Multidisciplinary optimisation of a CFRP wing cover

With the market introduction of both the Airbus A350XWB and the Boeing 787, Carbon Fibre Reinforced Plastics (CFRP) has been applied to primary structure of large commercial aircraft, as a means of enhancing overall performance. Both these aircraft are being developed and produced in a unique way where Airbus and Boeing are acting as System Integrators and using Risk Sharing Partners to develop the majority of the principal components. To support this new business and technological model it is necessary that the System Integrator has sufficient knowledge and tools to support the development of the components. Of particular interest are items such as the wing covers, as they are both heavy and expensive items, thus offering large opportunities for optimisation, in particular when the benefits of applying CFRP are considered. This creates the forum for this thesis, i.e. to thoroughly understand all factors that influence a CFRP wing cover, from which an optimisation methodology is developed, incorporating design constraints, while seeking the lightest weight solution, with a resultant Life Cycle Cost (LCC). Based on this, different solutions can be compared based on weight and LCC. In general stringer-stiffened panels are, from a weight perspective, the optimal configuration for wing covers, and thus are solely considered. Serendipitously, due to their prismatic shapes, buckling calculations of stringer-stiffened panels can be solved with reasonable accuracy and ease using the Finite Strip Method (FSM), as opposed to more time consuming methods such as the Finite Element Method. A suitable FSM program is available from ESDU, which when used in combination with a configured Excel spreadsheet can take into consideration constraints established from the extensive literature review. Once the lowest weight solution is obtained under buckling constraints, the solution is then checked for in-plane and if desired out-of-plane strength. Based on the structurally optimised wing cover, the manufacturing cost is calculated using a Process Based Cost Model (PBCM), which has been developed based on different CFRP materials for the skin and stringer fabrication, as well as suitable manufacturing and integration methods. In order to consider the LCC, i.e. all costs from cradle to grave, the PBCM factors in both the cost of recycling scrap material during manufacture and after retirement. Furthermore, when more than one solution is compared then the Economic Value of Weight Saving, which is based on the range equation, can be factored in to consider the financial benefit of weight saving. The optimisation methodology and PBCM has been evaluated on diverse wing cover examples, which has considered both uni-directional prepreg, non-crimp fabric and braids materials in combination with autoclave and liquid composite moulding techniques. The results demonstrated a trend which can be considered realistic, although the cost estimation is very much dependent on the assumptions made. In conclusion, the thesis and the optimisation methodology can be used to compare different configurations.EThOS - Electronic Theses Online ServiceGBUnited Kingdo