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

Mineral Filler Hybridization in Recycled Polyethylene Terephthalate

This study focused on evaluating the mechanical, thermal, and morphological properties of recycled polyethylene terephthalate (RPET) hybrid mineral-filled composites containing fine acicular wollastonite, mica phlogopite, and talc platelets. Depending on the filler content, both single mineral-filled composites as well as hybrid mineral–filler composites were investigated. The maximum nominal filler content was set to 20% by weight with varying ratios for combinations of the wollastonite–mica and wollastonite–talc composites, respectively. Aside from the tensile, compression, and flexural properties, the heat distortion temperature and degree of crystallinity were carried out. Moreover, the dynamical response of the hybrid mineral-filled composites on different frequencies (1 Hz, 2 Hz, 5 Hz, and 10 Hz) was considered. By using scanning electron microscope photography, the fracture surface and the morphology of the composite material were observed. The results demonstrated enhanced stiffness, strengths, and thermal stability for all hybrid mineral-filled composites. In particular, the wollastonite–talc-filled RPET composites revealed a good compatibility and showed the most beneficial results

Untersuchungen zum Umformen von Feinblechen aus Magnesiumknetlegierungen

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Design and Analysis of Mechanical Gripper Technologies for Handling Mesh Electrodes in Electrolysis Cell Production

As climate change accelerates, the demand for green energy is growing significantly. Due to the intermittent nature of renewable energy, the need for long-term storage is growing at the same rate. Hydrogen presents itself as a promising option for long-term storage, the need for electrolysis plants is therefore increasing significantly. Solutions for scaling up alkaline electrolysis production are currently lacking, particularly in the handling of large mesh electrodes. Therefore, new gripping concepts and technologies have to be developed to enable precise and automated handling of the electrodes, as established handling methods have failed due to the porous, limp and weakly magnetic material properties. This paper therefore presents two new ingressive gripping technologies in the form of individual gripping elements, which can later be combined to form a gripper. The technologies identified here are based on a threaded structure on the one hand and a spiral-like structure on the other. Depending on the mesh geometry to be handled, the gripper elements are designed accordingly. In order to grip the mesh, the gripping element is moved forward and turned at the same time. For verification, sample gripper elements were tested for a range of mesh geometries. The individual gripper elements were produced using selective Laser melting process (SLM), as the fine structures would be exceedingly challenging as well as very costly to produce using conventional manufacturing methods. The gripper elements were tested for three aspects of the handling process: Reliability, retention force and precision. The results in finer meshes show a high holding force for the spiral structures, while the screw structures show more potential in precision. In terms of performance in finer meshes, both structures have potential for use in mesh electrodes, with the low retention force of the screw structures due to the increasing imprecision of the SLM process

Grasp Point Optimization and Leakage-Compliant Dimensioning of Energy-Efficient Vacuum-Based Gripping Systems

Vacuum-based handling, used in many applications and industries, offers great flexibility and fast handling processes. However, due to significant energy conversion losses from electrical energy to the useable suction flow, vacuum-based handling is highly energy-inefficient. In preliminary work, we showed that our grasp optimization method offers the potential to save at least 50% of energy by a targeted placement of individual suction cups on the part to be handled. By considering the leakage between gripper and object, this paper aims to extend the grasp optimization method by predicting the effective compressed air consumption depending on object surface roughness, gripper diameter and gripper count. Through balancing of the target pressure difference and the leakage tolerance in combination with the gripper count and gripper diameter, significant reductions of the compressed air, use and therefore the overall energy consumption, can be achieved. With knowledge about the gripper-specific leakage behavior, in the future it will be straightforward for system integrators to minimize the need for oversizing due to process-related uncertainties and therefore to provide application-specific and energy-optimized handling solutions to their customers

Verfahrensentwicklung zur Herstellung von hybriden FVK/Stahl-Strukturen mittels eines neuartigen Blechverbindungselementes : Berichtszeitraum 01.05.2015 bis 31.08.2017

The research project „Process Development for Manufacturing of Hybrid FRP-Steel Structures by Means of a Novel Sheet Joining Element“ addressed the investigation of applying the widespread technology of resistor element welding to joining two dissimilar materials (steel and fiber-reinforced thermoplastic). A base plate equipped with three or more joining pins worked as basic concept. The pins are meant to penetrate the locally molten thermoplastic thus working through the FRP material while leaving as majority of fibres intact. Sticking out of the back side of the FRP material, the pins were then welded to a steel component upon contact through conventional spot welding. Thereby, electric energy is induced through the head plate and the pins. The proposed joining elements can be manufactured in an industrial die-cutting and forming operation. However, the three required process steps (element manufacturing, FRP penetration and welding) constitute contrary target goals in terms of geometrical pin design and material selection. During the research project, each individual process was developed and eventually optimized in such a way that ensured a hybrid joint with sufficient strength. Therefore, element geometries were adapted continuously. In conclusion, the goals of the research project were so achieved.Bundesministerium für Wirtschaft und Energi

Increasing the Energy-Efficiency in Vacuum-Based Package Handling Using Deep Q-Learning

Billions of packages are automatically handled in warehouses every year. The gripping systems are, however, most often oversized in order to cover a large range of different carton types, package masses, and robot motions. In addition, a targeted optimization of the process parameters with the aim of reducing the oversizing requires prior knowledge, personnel resources, and experience. This paper investigates whether the energy-efficiency in vacuum-based package handling can be increased without the need for prior knowledge of optimal process parameters. The core method comprises the variation of the input pressure for the vacuum ejector, compliant to the robot trajectory and the resulting inertial forces at the gripper-object-interface. The control mechanism is trained by applying reinforcement learning with a deep Q-agent. In the proposed use case, the energy-efficiency can be increased by up to 70% within a few hours of learning. It is also demonstrated that the generalization capability with regard to multiple different robot trajectories is achievable. In the future, the industrial applicability can be enhanced by deployment of the deep Q-agent in a decentral system, to collect data from different pick and place processes and enable a generalizable and scalable solution for energy-efficient vacuum-based handling in warehouse automation

Computational Manufacturing for Multi-Material Lightweight Parts

In this contribution, a computational approach for the manufacturing of multi-material lightweight parts is presented. For an efficient online optimization procedure, a proper orthogonal decomposition on offline obtained numerical results is carried out to construct a surrogate model. The functionality of the proposed framework is demonstrated on a use case study of a multi-material component consisting of a sheet metal basic structure and a plastic reinforcement structure. The manufacturing process chain consists of a deep drawing process followed by an injection molding process of short fiber reinforced plastics. The proposed methodology provides a fast and accurate computational model for structural properties with respect to the process settings

Studie zum One-Shot Prozess an Holz-Kunststoff-Verbunden

Environmental changes force industries to use renewable and degradable materials for lightweight solutions to solve weight and therefore CO2. One highly prioritized topic is the combination of wood materials with biodegradable plastics. Especially when processing these materials, it is essential to develop efficient processes to reduce obstacles and enable the application in serial use. To take advantage of the mechanical behaviour of the wood structure it is necessary to investigate the combination of thin solid wood with plastic. Regarding large-scale production, an injection moulding process is addressed in this study. When processing raw material cutting operations are used. To use the shear cutting process has several advantages: it is a cost effective process with short cycle times. Also no thermal influence or water immersion occur on the working material (like in laser beam or water jet methods), so material sensitive on this can be worked by shearing. But as a disadvantage a working force is applied. This work aims to show the findings this working fore on 5mm wood solids and the influence of the created surface on the bonding between plastic and wood cutting edge. The process connections and dependencies of shear cutting and injection moulding are investigated. Different wood materials were used to analyse the effects of cutting and material parameters (e.g. moisture, forces) on the cutting edge quality (e.g. structural damage). To detect the effect of different cutting edge qualities on the joint between wood and plastic component tensile specimen were tested.Umweltveränderungen zwingen die Industrie, erneuerbare und abbaubare Materialien für Leichtbaulösungen zu verwenden, um Gewicht und damit CO2 einzusparen. Ein hochpriorisiertes Thema ist die Kombination von Holzwerkstoffen mit biologisch abbaubaren Kunststoffen. Besonders bei der Verarbeitung dieser Materialien ist es wichtig, effiziente Prozesse zu entwickeln, um Hindernisse für den Markteintritt zu reduzieren und die Anwendung im Serieneinsatz zu ermöglichen. Um das mechanische Verhalten der Holzfaserstruktur auszunutzen, ist es notwendig, die Kombination von dünnem Holz mit Kunststoff zu untersuchen. Im Hinblick auf die Großserienproduktion wird in dieser Studie das Spritzgussverfahren adressiert. Die Anwendung des Scherschneidverfahrens hat einige Vorteile: Es ist ein kostengünstiges Verfahren mit kurzen Zykluszeiten. Auch findet keine thermische Beeinflussung oder Eintauchen in Wasser auf das zu bearbeitende Material statt (wie beim Laserstrahl- oder Wasserstrahlverfahren), sodass darauf empfindliches Material durch Schneiden bearbeitet werden kann. Als Nachteil wird jedoch eine Arbeitskraft aufgebracht. Ziel dieser Arbeit ist es, die Erkenntnisse zu zeigen, die die scherende Bearbeitung an 5mm Holzwerkstoffen und der folgende Einfluss der erzeugten Oberfläche auf die Verbindung zwischen Kunststoff und Holz hat. Die Prozesszusammenhänge und -abhängigkeiten von Scherschneiden und Spritzgießen werden untersucht. Es wurden verschiedene Holzwerkstoffe verwendet, um die Auswirkungen von Schnitt- und Materialparametern (z.B. Feuchtigkeit, Kräfte) auf die Schnittkantenqualität (z.B. Strukturschäden) zu analysieren. Um den Einfluss unterschiedlicher Schnittkantenqualitäten auf die Verbindung zwischen Holz- und Kunststoffbauteil zu erkennen, wurden Zugproben untersucht