Investigations for the Optimization of Metal Freeforming using the ARBURG freeformer

The ARBURG freeformer represents an additive manufacturing system for producing thermoplastic components using commercially available polymer granulate. This fabrication process offers the potential to use feedstocks known from the metal injection molding (MIM) sector to manufacture so-called green parts. These parts consist of 60 Vol.-% stainless steel powder and 40 Vol-% organic polymer binding system. By debinding and sintering these green parts, it is possible to economically produce full metal components with mechanical properties comparable to metal injection molding. In this publication, the process of producing stainless steel parts with ARBURG plastic freeforming will be presented. The mechanical properties and part density are optimized by varying manufacturing parameters and raw materials. Furthermore, concepts to optimize and increase the service life of the nozzle are shown and discussed. An increase of at least 250% could be achieved by plasma nitriding and coating components of the discharge system

A Methodology for Sustainability Assessment and Decision Support for Sustainable Handling Systems

Sustainable manufacturing is an important goal to reduce the carbon footprint and securing the economic success of companies. To reach sustainable manufacturing it is also necessary to use sustainable equipment. For this purpose, the sustainability indicators of the asset during its whole life cycle need to be considered for decision making during the design and selection of equipment. Missing analysis methods as well as missing awareness of the importance are obstacles in decision making. Therefore, a multi-criterial analysis method for handling systems for decision empowerment is presented in this paper. The presented methodology enables the engineer to analyze the suppliers for decision making in the purchasing process as well as the identification of weak points regarding sustainability in the handling systems. The methodology offers the possibility of analyzing a system of several parts as a whole, rather than just individual parts. The methodology is implemented in a usable software prototype which has a graphical interface for the data input and can be connected to conventional databases. The usability of the tool is shown with a handling system consisting of an industrial robot and a gripping system

Systematic quantitative investigation of the unscrewing process with regard to breakaway torque

Threaded connections make up the majority of separable connections used today. Their disassembly behaviour strongly depends on the conditions during the life-phase. With the trend towards circular economy, disassembly particularly for remanufacturing requires automation. For production systems this mandates a certain capability of adaptation towards different product conditions. In the regarded case of dismantling threaded connections, this is the automatic selection of appropriate robot tools. One important criterion for the tool-selection is the breakaway torque, which strongly depends on friction parameters within the threads and the head surface. Those are influenced by e.g. corrosion and head type. In this contribution, the results of a systematic experimental investigation of the breakaway torque of threaded connections is presented. The aim of the contribution is to determine the influence on the breakaway torque of typical factors appearing in automated disassembly systems. Therefore, a total of 90 experiments are conducted which include five factors: Nominal diameter; Screw head type; Corrosion; Plate material; Applied torque during assembly

Lightweight creativity methods for idea generation and evaluation in the conceptual phase of lightweight and sustainable design

Regarding the implementation of lightweight design in products, there are various guidelines, principles and methods that support the developers methodically throughout the entire design process. Such methods often pursue the goal of optimizing an existing product by reducing the amount of consumed material (e.g., topology optimization). A more effective way to apply lightweight design lies in fostering the creativity and intuitiveness of engineers to develop miscellaneous concepts with the capability to provide far greater mass reductions in contrast to smaller efficiency enhancements. Supported through the breakdown of assemblies via thinking in terms of functions along the paradigm of systems engineering, existing creativity techniques (e.g., “brainstorming” or “6-hats-method”) and evaluation methods (e.g., “point scoring”) for idea generation and evaluation have been analyzed and rethought from a lightweight and sustainable design perspective resulting in so called lightweight creativity methods (LWCM). The methods were tested on a use case from the field of robotics, which enabled the identification of the potential of LWCM for a lightweight and sustainable design

Automated Configuration of Gripper Fingers from a Construction Kit for Robotic Applications

Gripper finger design is a complex process that requires a lot of experience, time, and effort. For this reason, automating this design process is an important area of research that has the potential to improve the efficiency and effectiveness of robotic systems. The current approaches are aimed at the automated design of monolithic gripper fingers, which have to be manufactured additively or by machining. This paper describes a novel approach for the automated design of gripper fingers. The motivation for this work stems from the increasing demand for flexible, adaptable handling systems in various industries in response to the increasing individualization of products as well as the increasing volatility in the markets. Based on the CAD data of the handling objects, the most suitable configuration of gripper fingers can be determined from the existing modules of a construction kit for the respective handling object, which can significantly reduce the provisioning time for new gripper fingers. It can be shown that gripper fingers can be effectively configured for a variety of objects and two different grippers, increasing flexibility in industrial handling processes

Supersymmetry of Anti-de Sitter Black Holes

We examine supersymmetry of four-dimensional asymptotically anti-de Sitter (AdS) dyonic black holes in the context of gauged N=2 supergravity. Our calculations concentrate on black holes with unusual topology and their rotating generalizations, but we also reconsider the spherical rotating dyonic Kerr-Newman-AdS black hole, whose supersymmetry properties have previously been investigated by Kosteleck\'{y} and Perry within another approach. We find that in the case of spherical, toroidal or cylindrical event horizon topology, the black holes must rotate in order to preserve some supersymmetry; the non-rotating supersymmetric configurations representing naked singularities. However, we show that this is no more true for black holes whose event horizons are Riemann surfaces of genus $g>1$, where we find a nonrotating extremal solitonic black hole carrying magnetic charge and permitting one Killing spinor. For the nonrotating supersymmetric configurations of various topologies, all Killing spinors are explicitly constructed.Comment: 27 pages, revtex, no figures. Minor errors corrected. Final version to appear in Nucl. Phys.

Additive-Subtractive Process Chain for Highly Functional Polymer Components

Additive manufacturing processes offer the possibility of producing components without using tools. Especially in mobility, new technologies are needed to make geometrically complex, functionally integrated and highly precise components. The fused filament fabrication (FFF) process is an additive manufacturing technique that offers easy handling and a large range of materials. However, the FFF process has a considerable shortcoming in dimensional accuracy. A process hybridization consisting of additive and subtractive steps was developed to eliminate this shortcoming. Applying subtractive work steps enables the precise integration of inserts and, thus, the production of highly functional polymer components. For this purpose, suitable demonstrators are derived from an example of a stator of a double-sided axial flux machine and the manufacturing process with the different working steps (additive & subtractive) is demonstrated. The focus is on increasing the dimensional accuracy and more precise integration of the inserts with the help of subtractive steps. Furthermore, non-planar overprinting during the additive manufacturing steps was investigated. The advantages of the combination of subtractive processing and non-planar printing were concluded