Advanced Materials Research Vol. 907

Abstract: In all areas of technology, the demand for high-quality, competitive and more valuable products is rising steadily. One approach to increase the value of manufactured products is the integration of electronic components in load carrying structures. These new products, which combine electrical and mechanical components synergistically, are called smart products. They consist of a passive structure and integrated electronics or smart materials. In addition to their mechanical properties they are also able to sense, to actuate or to transmit energy or data. The resulting product architecture requires both a mechanical and an electronic design in order to save subsequent assembly costs. Since further components are required to evaluate and control as well as to supply energy, all of those components need to be connected and integrated into the smart product. However, the main prerequisite for the marketability is the possibility of low-cost manufacturing and a robust mass production. Nowadays processes for the manufacturing of smart products do not fulfill the requirements for a sustainable mass production in a satisfying way as long as metallic structures are used. The authors deploy the forming technologies roll forming and sheet metal hydroforming to form sheets with applied flat electronics. Since the components are applied prior to the forming process, small and difficult to access installation spaces can be used effectively in the product architecture. The incremental bulk forming process rotary swaging is employed to integrate piezoceramics during the forming procedure without any additional joining elements. Challenges resulting from the chosen integrative manufacturing approach are the prevention of new kinds of failure modes and additional requirements for defined residual stress states. These challenges lead to extended process design requirements, which will be discussed in the paper in detail.

Abstract: The rapid manufacturing of a great variety of variant products is gaining importance in global competition. Customers are increasingly demanding products which are matched to their specific demands. The production of these customized variants gives a competitive advantage, but also affords a high inner variance which leads to high production costs. Almost every step in the process of making a product is capable of generating variants. A key element in variant management is to make the variants as late as possible in order to exploit economies of scale in the earlier stages of production and to minimize the complexity of production. The technique of the highly flexible final production stage consists in achieving a late emergence of variants by integrating the variant-specific manufacturing processes into the assembly stage and enabling a mass production within a preliminary production stage at the same time. This means abandoning the conventional distinction between manufacturing and assembly in favour of a division into the preliminary, variant-neutral production stage and a final production stage where the variants take shape. The final production stage includes all the processes that determine variants. The complete manufacture of variant-neutral parts and subassemblies takes place in the preliminary production stage, as does the pre-manufacturing of those parts and sub-assemblies which are to undergo final manufacturing as variants in the final production stage. In order to apply the technique of the highly flexible final production stage successfully an integrated approach is necessary which is presented in this paper.

Abstract: In gas turbines and turbo jet engines, high performance materials such as nickel-based alloys are widely used for blades and vanes. In the case of repair, finishing of complex turbine blades made of high performance materials is carried out predominantly manually. The repair process is therefore quite time consuming. And the costs of presently available repair strategies, especially for integrated parts, are high, due to the individual process planning and great amount of manually performed work steps. Moreover, there are severe risks of partial damage during manually conducted repair. All that leads to the fact that economy of scale effects remain widely unused for repair tasks, although the piece number of components to be repaired is increasing significantly. In the future, a persistent automation of the repair process chain should be achieved by developing adaptive robot assisted finishing strategies. The goal of this research is to use the automation potential for repair tasks by developing a technology that enables industrial robots to re-contour turbine blades via force controlled belt grinding.

Abstract: At present, the use of clinching is mainly restricted to thin sheet metal. Here the joining technology is used for assemblies in mass production due to its great coast efficiency. However, the branches of industry working with thick sheet metal (utility and rail vehicle engineering, shipbuilding and general structural steel engineering) represent a major potential for using clinching technology. Unfortunately, the suitability of clinching for connecting jobs with substantially greater sheet metal thicknesses has neither been sufficiently investigated, nor are there suitable toolsets among system manufacturers that are adapted to the larger overall sheet metal thicknesses. Instead, the state-of-the-art for ascertaining tools for larger sheet metal thicknesses and point dimensions is trial and error accepting the high costs caused by producing a large number of tools and experiments. This paper demonstrates some analytical approaches to this problem and how suitable they are to describing the process of clinching in comparison to the potential of calculation with FEA.

Abstract: Manufacturing companies in high-wage countries can pursue two strategies to make up for their competitive disadvantage due to the unfavourable cost structure. They can either resort to an individualisation of the products or make use of economies of scale in production by high numbers. Only very few companies however are able to reconcile both strategies. One way to meet these requirements is in the use of flexible, automated systems. Here, the feeding process for automated, flexible assembly systems often represents a bottleneck. Conventional feeding systems come up against their limits. They are often only able to achieve the required output as redundant systems, and they are limited in their flexibility and set-up capability due to the mechanical design. Innovative solution approaches in this field can be offered by the aerodynamic orientation technology and the aerodynamic separation technology. In contrast to conventional feeding systems, these processes, due to their basic operating principle, already have high potential with regard to variant neutrality, flexibility and output. Aerodynamic part orientation technology takes advantage of the asymmetry of workpieces in order to orientate them with the aid of air impulses. In the case of aerodynamic part separation technology, workpieces are separated from a pile of material by an air vortex and individually transported out of the system. It has been shown that these technologies, due to their functional principle and the simple mechanical construction as compared to conventional systems, offer greater flexibility, are less prone to failures and can in some cases more than double the output.

Abstract: In nearly all sectors, the competitive situation for producing companies will further exacerbate with the consequence of a growing price pressure. In addition, the environment of producing companies becomes more and more turbulent. Mass production is an important principle in order to handle the growing price pressure. But in order to make successfully use of this principle, companies have to be able to react fast to external and internal induced changes. Companies have to increase their changeability with expedient measures and an efficient use of resources. Therefore the knowledge about the interdependencies of the different areas in a producing company is important. The developed methodology enables to analyze and visualize the significant areas and their interdependencies in order to deduce effective measures for increasing the changeability.

Abstract: Companies producing in high-wage countries are increasingly challenged due to the necessary differentiation and cost pressure. The modular product platform approach is more and more used by these companies for structuring their product range in order to realise and deploy commonalities. This type of product architecture enables companies to produce nearly individual products without losing economies of scale across the product range. Economies of scale due to communalities result in decreased process costs, reduced development lead-time by uncoupling the development of modules and products as well as the augmentation of the technical product robustness. However, the design of modular product platforms itself causes new challenges regarding the product structuring, the process and organizational design. Recent approaches for the development of communalities through modular product platforms are focusing only the product itself. Since costs are mainly determined in the development phase but caused later in the production phase both product and production have to be taken into account. Furthermore, modular product platforms have a higher variety and diversity of elements since they represent the components, modules and functions of the entire product program. This paradigm shift from an integral product design to a modular product structure cannot be controlled with existing models and methods. Our paper confirms commonality has to be optimized by focusing both the product and production. Therefore we have designed a descriptive framework (commonality model) to display and optimize the commonality both in the product and the process. Furthermore, a product architecture development process that is superior to the individual product development processes was developed for the systematic design of commonalities. The approach presented in this paper focusses on the interactions between product and process parameters. In our approach these interactions will first be displayed based on the graph theory and then be optimized applying sensitivity analysis. By varying relevant parameters both on the product and process side constitutive features can be derived determining product and process standards in order to enhance the overall commonality level.

Abstract: In recent years microfluidic devices became of great interest, as they offer a wide range of bio-analytical and fluid processing applications through the utilization of size effects. Especially a mass manufacturing of disposable polymeric microfluidic devices by hot embossing or injection molding is expected to have high economic potential. It is known, that channels and areas showing a localized change in wettability can considerably improve fluid processing tasks like mixing or droplet generation. Chemical approaches, like the polymerization of lauryl acrylate, were successfully shown to achieve hydrophobic coatings for micro channels but are not suitable for a mass manufacturing. Since microstructures are known to provide water repellent properties of surfaces, this paper focuses on the applicability of diamond grooving and Diamond Micro Chiseling (DMC) processes for the manufacture of microstructured areas in brass molds inserts, in order to achieve hydrophobic properties of their replica. Major design features of structures, like a height range of 6 to 16μm or aspect ratios in between 0.5 and 3.2 are derived from the natural example of the lotus leaf. Molding is carried out by using a two component silicone filler. The performance of the replicated hydrophobic surfaces is evaluated by droplet contact angle measurements. After presenting methodology and results, the paper will conclude on how to transfer the investigated microstructuring methods to the manufacture of mold inserts for the replication of polymeric microfluidic chips with localized hydrophobic areas and channels.

Abstract: This paper presents the development of an active driven prosthesis for transfemoral amputees. At the beginning of the development process gait parameters are analyzed. Defined boundary conditions help to get the right technical parameters for a structured development process. During the following development process, different concepts for active driven knee prostheses are discussed. Essential components for active driven prosthesis systems are presented. The focus during the scientific work is the development of an active drive system for an active driven knee prosthesis. A first prototype of an active driven knee prosthesis is shown.

Abstract: Cochlear implant surgery on highly hearing impaired and deaf patients presents surgeons with major medical challenges. In advance of the operation, the surgeon must gain the necessary dexterity and topographical knowledge in the field of microsurgery. For these purposes human cadaver specimens are usually used but they are not sufficiently available. Therefore, our group from the University of Magdeburg researches and develops a manufacturing process for producing individual anatomical facsimile models (AFM) of the human ear bone, which originally simulate the cavity structure of the inner ear (cochlea, semicircular canals) by using rapid prototyping methods. For this production a variety of biomechanical data of the human ear bone are needed to recreate the later models with the same biomechanical properties. By using these obtained biomechanical data and the individual patient's CT data, stereolithography models of UV-sensitive epoxy resin can be produced. The models can be emulated to the biomechanical properties of the human bone by varying the curing process of the epoxy resin. Thus, the authentic drilling and milling properties give the surgeon the possibility to develop the skills needed in dealing with microsurgical instruments. At the same time the authenticity of the AFM promotes the study of the anatomical structure and the orientation of anatomical landmarks.