Advanced Materials Research Vol. 907

Abstract: Electric vehicles are in direct competition with conventionally powered cars. However, high prices currently result in a moderate acceptance and low market penetration. Producing companies have to attain new competencies in electric vehicle production as well as develop existing competencies at an early stage to be able to create attractive products for the customer. Requirements for costs, quality and scalability can be met due to purpose design, integrated product and process development, modularization of machinery and intense process know-how along with continuous consideration of alternative production processes. Nevertheless, designing new value added networks with a strategic fit among all participants remains to be done.

Abstract: The rising number of lithium ion batteries from electric vehicles makes an economically advantageous and technically mature disassembly system for the end-of-life batteries inevitable. The disassembly system needs to cope with the size, the design and the remaining state of charge of the respective battery system. The complex design resulting from the number and type of connection elements challenges an automated disassembly. The realisation of an automated disassembly presupposes the consideration of elements from Design for Disassembly throughout the battery system development. In this paper a scenario-based development of disassembly systems is presented with varying possible design aspects as well as different amounts of end of life battery systems. These scenarios point out the resulting implications on battery disassembly systems in short, medium and long term. Using a morphological box the best option for each disassembly scenario is identified and framed in a disassembly system design. The disassembly systems are explained and the core elements are introduced. Newly developed and innovative disassembly tools, such as a robot that allows a hybrid human-robot-working-space and an advanced battery cell gripper are introduced. The gripper system for the battery cells enables with an integrated sensor an instant monitoring of the battery cell condition. The proposed disassembly element is verified in an experimental test series with automotive pouch cell batteries.

Abstract: Today a criterion for the quality of modern machine tools is their efficient use of energy and resources. Competitiveness can only be maintained if the necessity to significantly reduce the energy consumption of machine tools, plants and facilities is put into practice. Another important aspect is the need to preserve our environment. In order to be able to energetically optimize machine tools, it is essential to know how much energy they consume at all. Hence, this paper deals with modelling the energy consumption to be expected from machining operations. Using these estimations and predictions provides a starting point for carrying out energetic optimizations. The method developed here is presented by example of turning operations. The model comprises the machine components directly associated with the cutting process as well as mediate components such as auxiliary units and peripherals. Experimental tests serve to verify the accuracy of the model. Then the energy consumed by individual components is provisionally categorized as well as their proportion of the total amount of energy consumption. Following this, it is possible to analyze the potentials for saving energy. In future it is intended to minimize and condense the complexity of the model so that it will be possible to simultaneously conduct the simulation on the NC control during the cutting operation. In this way it might become possible to influence the energy state of machine tools in realtime during machining, using expert knowledge about the adaptive control of components and drives, the adjustment of control parameters on the fly or the change of parameters such as cutting speed, feed rate and depth of cut. The investigations presented here were funded by the German Research Foundation within the Research Unit 1088 ECOMATION.

Abstract: In line with the striving for a more sustainable orientation in manufacturing systems and industrial pursuit of resource efficiency, companies are looking for efficient processes. The consumption of electrical energy and other resources during the manufacturing phase is considered by the ecological footprint. This study offers a conception for the determination of the ecological footprint within manufacturing systems based on life cycle assessments. The existence of basic data is a requirement for such an evaluation. Therefore, a holistic measurement system is presented which is adaptable to small as well as large scaled production environments and different usage scenarios, e.g. full scale measurement or detailed process analysis.

Abstract: The shape of cutting edge and cutting geometry changes in tool life due to wear. These geometrical changes of the tool are leading to non acceptable deviations from the demanded target geometry and a loss of cutting surface quality. Consequently the tool has to be inspected at regular intervals and be replaced or grinded if necessary. Prediction of such inspection intervals emerge as one of the challenges for an effective production. The inspection interval is dependent on tool life, which can be determined by cost intensive and elaborate experiments. Determination of a database containing tool life data for different production conditions actually lead to excessive waste of material and energy. Due to this fact, this paper presents a new procedure to predict the wear behavior of shear cutting tools based on a modified Archard wear model linked with finite element analysis (FEA). The Archard equation requires an empirical adjustment factor K. The intention of this paper is to highlight a potential approach to determine this coefficient without conducting long lasting tool life tests. A design method oriented approach in this paper is leading to a procedure to be able to determine wear coefficient using a chip cutting process. Though this adjustment can be accomplished within a few hours (time required for tool life test normally needs 14 days or more) with a material usage of only 0.5 % of the required sheet metal material compared to corresponding shear cutting tests. In future practitioners might look for accurate prognosis of amount of tool wear in order to reduce machine downtime and discarded parts significantly what finally saves energy, time and material.

Abstract: The automotive sector is one of the largest energy consumers in Germany. Requests from politics and industry to significantly reduce emissions require new developments during utilization as well as during production phase. In line with the framework concept "InnoCaT", where more than 60 companies and research facilities from Germany take part, possibilities for producing companies are developed and analyzed to reduce the resource and energy consumption and by this reducing costs along the entire process chain of car body manufacturing. One approach to design car bodies lighter and more efficiently is to use aluminium and high strength steels. By this means weight and sheet thickness are reduced. However higher strengths of the steels and the adhesion affinity of aluminium significantly increase the requirements regarding the used tool steel. Thus grooves or galling appear more frequent at highly stressed surfaces. To assure high lifetimes and by this increase especially the resource efficiency concerning use of material and setting-up times within the press plant, a local optimization at the highly stressed surfaces is necessary. For this a FEM/BEM-tool for a time efficient and exact calculation of the occurring tool loads for complex die profiles is developed. Based on this development of load calculation a shape-optimization is performed at the corresponding areas. After the geometric optimization of the tool a local laser surface treatment for further wear protection is carried out using laser cladding or laser alloying/ -dispersing. By combining the technologies a highly wear resistant surface is achievable, which increases the tool's lifetime as well as the reproducibility within production.

Abstract: Energy consumption and emissions are the two main sustainability issues of German companies. The main reasons for efficiency increase and emission reduction are not, as often proclaimed, energy costs, but the demands of customers and legislators for low carbon emissions. Particularly at machine level and process chain level various methods for analysis and improvement of the energy efficiency already exist. At factory level there is no systematic approach. The method Factory Carbon Footprint Design is an appropriate tool for that issue. The method is derived from the activity-based costing method and has two main parts: The Activity-based Carbon Footprint Accounting and the Target Carbon Footprint Design. Using the Activity-based Carbon Footprint Accounting, the carbon footprint of all energy consumers can be allocated to the goods produced in the factory. This contains not only the carbon footprint of the manufacturing machines, but also the periphal equipment and the administration and other indirect parts of the factory. The Target Carbon Footprint Design is a systematic approach to reduce the overall carbon footprint of a factory.

Abstract: The effectiveness of gas turbines can be improved significantly by decreasing the friction losses. Compared to smooth surfaces riblet-structures have been proven to reduce skin friction in turbulent flow up to 10 %. For the technical application on compressor blades in turbo machines, micro riblet-structures with a riblet width between 20 μm and 120 μm and a depth of the half width are required. Furthermore, the application on compressor blades needs ideal riblet-geometries with an aspect ratio of 0.5, trapezoid groove geometry and a shape accuracy of the compressor blade about 10 μm. This paper presents the relevant influencing factors on the overall shape accuracy as well as the riblet geometry in five axes grinding of riblet-structures on double curved compressor blades. The results show, that the shape accuracy is affected by the CAD data and the macro-geometry of the grinding wheel. Therefore, specialized requirements on the CAD data were defined in order to increase the shape accuracy. To decrease the influence of the grinding wheel geometry on the overall shape geometry, a method adjusting the grinding wheel geometry on double curved surfaces was developed. Furthermore, the effect of the 5 axes kinematic on the aspect ratio and the profile wear was examined.

Abstract: Resource efficiency in the commercial vehicle industry is highly dependent on the application profile of the vehicle. In order to assess the resource efficiency of commercial vehicles, the production, the usage and the product itself have to be taken into account. Therefore, a lifecycle oriented approach is necessary. This paper presents a lifecycle oriented assessment methodology for resource efficiency, including the three pillars production, usage, and product. First, resources consumed along the lifecycle of a commercial vehicle are identified and classified. In the second step, we show how to gather interdependencies between the pillars production, usage, and product as well as interdependencies within the pillars. The third step provides a decision model to evaluate suitable measures for increasing resource efficiency. The methodology is illustrated by an example from the commercial vehicle industry.

Abstract: Cylinder bore finishing requirements are defined by quality features such as roundness and cylindricity as well as by the manifestation of the surface profile. Honing is a proven manufacturing method s to achieve this. Undesirable distortions of the cylinder shape occur under operating conditions in a reciprocating internal combustion engine. These negatively affect the tribological system of piston, piston ring, and cylinder bore. As a result, efficiency deteriorates and oil consumption rises. The cylinder crank cases are finished in a defined tensioned state to compensate for distortions. This results in a highly complex manufacturing process and is only suited for compensating static distortions. Further increasing machining requirements resulting from strategies such as lightweight construction, downsizing, and friction reduction are pushing conventional honing methods to their technological limits.Adaptronic form honing constitutes a production engineering approach to manufacturing a free form in the cylinder bore. The objective is to keep inverse distortion geometries in store as macro shapes. These will then represent ideal cylinder shapes under the influence of distortion mechanisms in a defined engine operating range. Tool and process development and the analysis of machining results with respect to productivity, shape accuracy, and surface topography are presented and viewed as potential options for optimizing the tribological system of piston, piston ring, and cylinder bore. Other options such as shortening the process chain will be derived.