Applied Mechanics and Materials Vol. 805

Abstract: As the production of green products progressively influences customers’ purchase decisions, the development, assessment and controlling of energy sparing processes increasingly has to be focused. Here, one major industry sector that has to be considered is the field of electric drives manufacturing, as the main amount of industrial used energy is consumed in electric engines. Consequently, main research activities in this field focus on the development of stable processes guaranteeing high efficiency levels of the produced motors. However, aside from the products’ energy efficiency, also the energy consumptions of the actual manufacturing steps have to be improved. For this purpose, the present paper presents the main energy consumers within the assembly line of an industrial induction engine. It also explains main energy reduction measures, which were evaluated using a combined material and energy flow simulation. Hereby, the line’s base load as well as the peak load was reduced.

Abstract: The proliferation of energy management systems leads to new potentials of data acquisition that can deliver improved machine information through intelligent linking. In addition to energy controlling, the newly gotten database creates further use cases for advanced purposes. This paper presents an exemplary application of a diagnostic scenario for industrial robots. For this objective, data fusion of energy data and operating logs is necessary to obtain detailed knowledge of the behavior of a production system. Hereby, an online measurement system will be described, which helps to uncover inefficiencies in production systems.

Abstract: In times of rising energy costs and increasing customer awareness of sustainable production methods, many manufacturers take measures to reduce their energy consumption. However, after the realization of such activities the energy demand often tends to increase again due to e.g. leaks, clogged filters, defect valves or suboptimal parameter settings. In order to prevent this, it is necessary to quickly identify such increases by continuously monitoring the energy consumption and counteracting accordingly. Currently, the monitoring is either performed manually or by setting static threshold values. The manual control can be time consuming for large amounts of sensor data. By setting static threshold values only a fraction of the inefficiencies are disclosed. Another option is to use anomaly detection methods from the area of machine learning, which compare the actual sensor values with the expected ones. In this paper an overview about existing anomaly detection methods, which can be applied for this purpose, is presented.

Abstract: The energy efficient production of goods can only be used as a unique selling proposition, if reliable values for the energy consumption, caused by production and transportation, are determinable. Furthermore, the customer must be able to compare these values for different products. Using a consistent and standardized methodology for calculating these values along the value chain, this comparability can be achieved. Providing this information, as potentially required by the end customer or by law, the penetration of this methodology could be achieved, while obviously the comparably more energy efficiently produced goods would be more attractive for the (end) customer. Consequently, an incentive system would emerge, which motivates the companies to improve their energy efficiency throughout the complete value chain. The following paper presents the above-mentioned methodology along with a unified scheme for allocating the energy consumption of the production to products.

Abstract: The continuous change of the consumers’ behavior combined with the impact of new technologies to the shop-floor is a challenge for the classic and established line production. Due to the effects of mass-customization there is an increase of the variants of the products combined with a reduction of the number of units per variation. Therefore, it is necessary that the next generations of production lines, especially the assembling devices, have to be designed more adaptable. Regarding to business information systems this trend is realized by a progressive digital integration of the particular units. However, at the physical level of the value stream the sequenced units are linked to each other and arranged flow-orientated since Taylor. Particularly, for mass production the so called “line concept” is well established. This inflexibility of the physical material flow blocks the spread of mass-customization into established industrial sectors where linked manufacturing steps are common use. A product which is very individualized is not, or only with an additional expense, producible on such linked lines. Therefore, it is necessary to resolve the linking of the physical material flow similar to the digital integration of the work flow. The result will be a physically and digitally full-meshed network of production units with a high variability. Especially for a production of goods with a high variant diversity the benefits of a physically meshed production site are obvious. Each part gets its own and individual routing, which depends on the current machine availability, the set-up and other factors. Furthermore, a change of the general conditions during the manufacturing of the part can be considered and lead to an adaption of the routing. One of the most important parts of a flexible physical production network is the transport system, consisting of autonomous and smart entities which are interconnected with business information systems, products and machines.

Abstract: In contrary to the traditional injection molding process, the selective laser sintering process offers a nearly unlimited freedom of design. However, the dimensional accuracy of an SLS part is significantly influenced by the process, the material and its design. In order to achieve high accuracy, the parts need to be repositioned, parameters readjusted and parts consistently rebuilt in an iterative process. In industry this process leads to enormous consumption of process time and polymer powder.Increased dimensional inaccuracy is often caused by the accumulation of polymer melt and the resulting shrinkage effects. Thus, highly accurate SLS parts can be manufactured using three dimensional, filigree structures in order to replace volumetric part sections. In this paper, the potential of using 3D-structures, for enhancing SLS parts’ accuracy is shown. Thus, influencing parameters, such as positioning, scale, process time and geometry feature are systematically varied. Additionally the effect of adjacently positioned parts influencing the dimensional accuracy shall be investigated.

Abstract: In modern car bodies lightweight structures are used to achieve a reduction of energy consumption and CO₂-emissions. One of the most important lightweight materials is aluminum and its alloys. Current state of the art in automotive industry is utilizing precipitation hardenable aluminum alloys of the 6000 series whereas the crash-relevant strength is achieved by artificial ageing during the paint drying process. Due to newly developed coatings which provide faster curing at lower temperatures, post-forming ageing of the 6xxx alloys to satisfactory strength levels becomes more difficult. The aim of this study is to investigate the feasibility of employing high strength aluminum alloys of the 7000 series in order to reduce artificial ageing time and temperature while keeping required strength. Within this contribution, the influence of pre-straining and subsequent heat treatment on mechanical properties will be presented.

Abstract: Due to the increase of product complexity, 5 axes machining centers are becoming more and more important. Rotary tables are usually chosen for the 4th and 5th axis. Additional hydraulic or pneumatic mounting clamps are often needed on these tables. The feeding of the required media is realized by a so-called rotary manifold. For this application, commonly several rotary seals are used to seal the transmitted media. Different sealing materials, based on the carrier polymer PTFE, have been examined during this research. In tribological model tests, friction and wear characteristics have been investigated during an oscillating movement under dry run conditions and equal load spectrums (surface pressure). The counter running surfaces were specific textured as a result of various machining processes to research the effects of possible micro-and macroscopic patterning on the sealing system. The tribological behavior of the analyzed combinations and the topography of the counter surfaces have been evaluated.

Abstract: Reaction injection molding is a plastic processing method to produce net shape parts using reactive systems. By integrating semi-finished products as inserts, complex multi-layer parts can be generated in highly integrative and energy efficient processes. The material by far mostly used is polyurethane, a polymer which results from the reaction of isocyanate and polyol. By adding blowing agents, like for example water, to the polyol component, foamed parts can be realized. In contrast to thermoplastic injection molding a chemical reaction takes part during molding within the cavity. Therefore the processing parameters have a significant effect on this chemical reaction and on the properties of the finished part.In this work the influences of different processing parameters like for example mold temperature and injection volume on the resulting foam structure are investigated for reaction injection foam molding. Therefore multi-layer parts based on polyurethane materials (thermoplastic and reactive) were molded varying relevant processing parameters. The foaming took place within an open cavity. The resulting foam structures were characterized using scanning electron microscopy (SEM). Additional the multi-layer parts were characterized mechanically to reveal the resulting effects on the mechanical properties of parts containing a foamed reactive polyurethane component.

Abstract: Over the last decades ink-jet printing has developed in many applications. The direct writing of materials such as silver (for conductive circuits) or polymers (for insulation or second layer) is an attractive method to reduce costs and save raw materials. In this article we investigate the geometrical and electrical properties of conductive circuit lines on thermoplastic substrates, depending on the printing parameters such as line width, orientation of the lines and density of the printed drops (dots per inch = dpi)First the surface of the substrates is scanned by a confocal laser scanner. The substrates (size 60mm x60 mm) are subdivided in 80 x 80 parts with a side length of 0.8mm. The 2D roughness (S_a) of these little parts is calculated and as a result the locally solved roughness of the substrates is determined. Homogeneity and surface quality of the surfaces can be evaluated.On the different polymeric substrates conductors (length 25mm) are printed with a printing head with 16 nozzles and with different orientations (parallel, horizontal and in an angle of 45° to the movement of the printing head). Also different dpi numbers (600, 900 and 1200) are used and the line width in the bit pattern is increased from 1 pixel to 5 pixels. The line width in μm depending on the line width in pixel is measured. The quality of the printed lines is quantified by calculating the deviation of the printed lines to a “perfect straight line” with the same width. The resistivity of the conducting lines and the reliability of the process are determined.