Publications

Belt conveyor systems are an excellent way of conveying bulk material. With increasing load and transport distance, these systems become larger and energy efficiency becomes an important factor. Rollers are an integral part of belt conveyor systems. The running behaviour of idlers during operation has an impact on the energy efficiency of the entire system. The development of driven idlers is seen as one way to reduce the energy consumption of belt conveyor systems. This contribution shows that the investigation of conventional and driven idlers under different conditions is necessary and that a test rig for the investigation of these idlers has been developed at the Institut für Integrierte Produktion Hannover.

idlers, rollers, driven idler, bulk material handling

The Collaborative Research Centre 1153 (CRC 1153) “Process chain for the production of hybrid high-performance components through tailored forming” aims to develop new process chains for the production of hybrid bulk components using joined semi-finished workpieces. The subproject B1 investigates the formability of hybrid parts using cross-wedge rolling. This study investigates the reduction of the coating thickness of coaxially arranged semi-finished hybrid parts through cross-wedge rolling. The investigated parts are made of two steels (1.0460 and 1.4718) via laser cladding with hot-wire. The rolling process is designed by finite element (FE)-simulations and later experimentally investigated. Research priorities include investigations of the difference in the coating thickness of the laser cladded 1.4718 before and after cross-wedge rolling depending on the wedge angle, cross-section reduction, and the forming speed. Also, the simulations and the experimental trials are compared to verify the possibility of predicting the thickness via finite element analysis (FEA). The main finding was the ability to describe the forming behavior of coaxially arranged hybrid parts at a cross-section reduction of 20% using FEA. For a cross-section reduction of 70% the results showed a larger deviation between simulation and experimental trials. The deviations were between 0.8% and 26.2%.

cross-wedge rolling, hybrid forming, FEA, coating thickness

In order to reduce CO2 emissions, it is necessary to know the emissions of operational processes. The Institut für Integrierte Produktion Hannover gGmbH has developed a software demonstrator which shows ecological-logistic cause-effect relationships. Internal and logistical processes can be investigated with regard to CO2 emissions, costs and process duration. Comparisons of different alternatives illustrate differences and show savings potentials of CO2.

ecology, logistics, CO2

Demographic change and the associated population growth in large cities make it increasingly difficult to create affordable housing. There is also a lack of available building land for potential new buildings. One approach to alleviate the housing shortage in large cities is modular building post-compaction. In this context, prevailing framework conditions are characterized by limited available space, a complex infrastructure or the consideration of the burden on residents. The lack of description models for associated construction sites, as well as for the organisation and control of necessary processes, still stand in the way of their widespread use. This refers in particular to the interactions of the parameters mentioned and their effect on the logistic performance of such a construction site. This article therefore describes a method for the organization and control of construction site processes in the modular building post-compaction with the aim to be able to plan and carry out such con-struction projects efficiently and with little effort. The users shall be provided with a process description of the planning of construction site equipment and process flow, as well as with a decision support in case of disturbances of the process in the operative operation.

urbanization, demographic change, construction sites, production planning and control

Within the Collaborative Research Centre (CRC) 1153 “Tailored Forming “the manufacturing of hybrid bulk components is investigated. Therefore, a process chain consisting of joining, forming, milling and quality control has been established by multiple subprojects.Within subproject B1 of the CRC forming of hybrid parts by the incrementally forming cross-wedge rolling (CWR) process is investigated. The superior aim is to determine process limits and capabilities, when forming parts consisting of different materials joined by varying technologies.

In this paper, the investigation of cross-wedge rolling of serially arranged hybrid parts made of steel and aluminum is described. The focus of the research presented in this publication is the displacement of the joining zone of hybrid parts due to the cross-wedge rolling process. Therefore, finite element simulations have been developed, that allow the investigations of hybrid solid components. After simulation of various variations of the cross-wedge rolling process, i.e.  differently shaped tools and forming velocities, experimental trials were carried out with identical parameter sets. A comparison of simulation and experiment, showed that the simulation model is capable of describing the cross-wedge rolling process of hybrid parts. The standard deviation of the displacement of the joining zone between simulation and experimental trials is 8.8% with regard to all investigated cases.

tailored forming, cross-wedge rolling, material forming, aluminum, steel

Within the Collaborative Research Centre (CRC) 1153 Tailored Forming a process chain for the manufacturing of hybrid high performance components is developed. Exemplary process steps consist of deposit welding of high-performance steel onto low cost steel and pre-shaping the component by cross-wedge rolling (CWR), supported by an optical quality control system. A combination of a fringe projection profilometry setup with a thermal imaging camera is used to monitor the components before and after the CWR process. Both geometry and thermal imaging data are combined, assigning temperature values to 3D data points.
In this paper, the acquisition of combined temperature-geometry data is described. The data before and after the CWR is compared to the input and the result data of the forming simulation that was used to design the CWR process. The comparison shows the quality and sustainability of the heating process as well as the influence of the transportation of the hot component prior to forming. Additionally, the accuracy of the used simulation model and software are evaluated by data examination. The examination shows the limits of idealised and simplified assumptions for the simulation, e.g., a homogeneous temperature distribution before forming or the modelling of the heat transfer on contact surfaces.

tailored forming, cross-wedge rolling, material forming, aluminum, steel, optical measurement

Within the Collaborative Research Centre 1153 “Tailored Forming“ a process chain for the manufacturing of hybrid high performance components is developed. Exemplary process steps consist of deposit welding of high performance steel on low-cost steel, pre-shaping by cross-wedge rolling and finishing by milling.
Hard material coatings such as Stellite 6 or Delcrome 253 are used as wear or corrosion protection coatings in industrial applications. Scientists of the Institute of Material Science welded these hard material alloys onto a base material, in this case C22.8, to create a hybrid workpiece. Scientists of the Institut für Integrierte Produktion Hannover have shown that these hybrid workpieces can be formed without defects (e.g. detachment of the coating) by cross-wedge rolling. After forming, the properties of the coatings are retained or in some cases even improved (e.g. the transition zone between base material and coating). By adjustments in the welding process, it was possible to apply the 100Cr6 rolling bearing steel, as of now declared as non-weldable, on the low-cost steel C22.8. 100Cr6 was formed afterwards in its hybrid bonding state with C22.8 by cross-wedge rolling, thus a component-integrated bearing seat was produced. Even after welding and forming, the rolling bearing steel coating could still be quench-hardened to a hardness of over 60 HRC. This paper shows the potential of forming hybrid billets to tailored parts. Since industrially available standard materials can be used for hard material coatings by this approach, even though they are not weldable by conventional methods, it is not necessary to use expensive, for welding designed materials to implement a hybrid component concept.

tailored forming, cross-wedge rolling, hard material coatings, PTA

By using digital tools in the factory planning process, the planning quality can be improved and the duration of the project can be shortened. In order to exploit these potentials, data consistency must be guaranteed throughout the planning process. In this article, digital factory planning tools, used at the Institut für Integrierte Produktion Hannover (IPH), will be presented and their applications and requirements will be discussed.

digital factory planning, factory planning process, data consistency, digital tools

Multi-stage process chains are often used for the efficient production of complex geometries. These consist of a homogeneous heating, one or more preform stages and the final forging step. Via inhomogeneously heated blanks, the process chains are to be simplified or shortened. This is to be achieved by setting several, clearly defined temperature fields in which different yield stresses are present. These can influence the material flow, leading to an easier production of complex parts.

inhomogeneous heating, bulk forming, preforming processes

By automating process steps, additive manufacturing can be integrated into industrial value chains. The Institut für Integrierte Produktion Hannover (IPH) gGmbH has been designing a process chain linking 3d printers and mounting stations automatically.

additive manufacturing, 3D printing

To this day, the design of preforms for hot forging processes is still a manual trial and error process and therefore time consuming. Furthermore, its quality vastly depends on the engineer’s experience. At the same time, the preform is the most influencing stage for the final forging result. To overcome the dependency on the engineer’s experience and time-consuming optimization processes this paper presents and evaluates a preform optimization by an algorithm for cross wedge rolled preforms. This algorithm takes the mass distribution of the final part, the preform volume, the shape complexity, the appearance of folds in the final part and the occurring amount of flash into account. This forms a multi-criteria optimization problem resulting in large search spaces. Therefore, an evolutionary algorithm is introduced. The developed algorithm is tested with the help of a connecting rod to estimate the influence of the algorithm parameters. It is found that the developed algorithm is capable of creating a suitable preform for the given criteria in less than a minute. Furthermore, two of the five given algorithm parameters, the selection pressure und the population size, have significant influence on the optimization duration and quality.

preform optimization, genetic algorithm, cross wedge rolled, adaptive flash

Bulk-formed components are used in many applications in automotive and plant engineering. The conditions under which the components are manufactured, often at more than 800°C and thousands of tons of forming force, lead to high die wear. One way to reduce wear is to use suitable protective coatings. Initial basic investigations showed that the use of hard Diamond-like Carbon (DLC) wear-resistant coatings can significantly reduce the tribological effects on the die surface. With new methods such as the use of multilayer layer coatings and temperature measurement on the die surface by use of thin layer sensors, the potential of wear protection for semi-hot massive forming is to be investigated and expanded.

DLC, hot forging, wear

Drones are often used in outdoor areas. Though drone are able to do more, e.g. to measure and digitalize the indoor layout structure of production environments. Further more it is possible to plan the production structure directly in the digital model with image processing algorithms. The combination of both step allows a faster and more efficient production planning process. 

drone, layoutscan, production planning, digitalization

The melt level and oxide layer quantity in an aluminum melting furnace cannot be monitored by contact sensors, since the melting bath is not accessible due to the high holding temperature (above 600°C). Therefore, the method of monitoring the melting bath by means of optical sensors is investigated for the first time. For this purpose, suitable optical measuring systems can be applied which will be able to record the melting bath. The height change of the melt is to be elaborated by means of image analysis and any oxide layer on the bath surface is to be detected.

aluminum melting furnace, metling bath monitoring, oxide layer

Abstract: For factory planning projects the layout capturing and layout processing process need a huge amount of effort, because they are typically done by hand. These processes could be accelerated and optimized by using a drone and automated analysis algorithms. Furthermore, this article shows a way to raise the digitization level for industrial processes. The key aspect lies on the usage of a drone in indoor environment and the processing of three-dimensional point cloud models for factory planning processes.

drone, factory planning, 3D-factory layout, object recognition

For the establishment of innovative manufacturing processes, consistent results and increased tool life is very important. When using slider tools in multidirectional forging processes, tool life identification has not been occurred yet. For the industrial implementation of slider tools, the influence of different process parameters on the resulting tool life is to be determined and a construction guideline for tool life increasement is created.

multi-directional forging, tool life optimization, design guidelines, toolmaking

The CO2 emissions of the logistics sector and the resulting environmental impact are continuously increasing. Rising costs for energy and resources, increased sensitivity of customers, changed legal bases and the impending climatic change force producing enterprises to ecologically-oriented rethink. The lack of knowledge about interdependencies, quantitative effects of actions and parameter characteristics prevents SMEs from the implementation. A holistic ecological-logistical impact model with software implementation can support SMEs reaching their potential. Requirements for the model and fundamental relationships between logistic parameters and ecological target values are presented in this publication.

SME, logistic, ecology

Since 2015 the Mittelstand 4.0 Centre of Excellence "Mit uns digital!" informs SMEs in Lower Saxony and Bremen about the opportunities and challenges of digitalisation. Now the funding from the Federal Ministry of Economic Affairs was renewed.

digitalization, industry 4.0, SMEs

Material efficiency and the development time of a forging sequence are decisive criteria for increasing the economic efficiency in the production of complex forgings. SMEs can often only interpret forging sequences in a shortened form due to insufficient capacities and high competitive pressure. Therefore, a generally valid method is to be developed that automatically generates multi-stage, efficient forging sequences based on the mass distribution of any forged part.

automated process design, die forging, resource efficiency

More and more players in the German wind energy sector are concerned with the question of how to deal with the aging German wind fleet, as around 5,200 turbines will simultaneously reach the end of the feed-in tariff funding period of the Renewable Energy Sources Act (EEG) for the first time at the end of 2020. Around 8,000 wind turbines will follow by the end of 2025, as shown in Figure 1. Operators of affected wind turbines will then have the choice between (I) continuing to operate the old turbine within the framework of direct marketing on the European Power Exchange, (II) repowering the old turbine by a new and more efficient wind turbine at plant-specific feed-in premium levels tendered in the German renewable energy auctions or (III) decommissioning the respective plant finally.

However, the question of choosing the right option arises not only for the operators themselves, but also for various other players in the wind energy sector:

Project developers, turbine manufacturers, and investors are interested in evaluations of plant-specific repowering potentials in the existing wind turbine fleet in order to provide operators with targeted support in implementing new projects; dismantling contractors and disposal companies particularly search for derivatives of plant-specific dismantling potentials and the associated disposal and recycling flows in order to enable optimal handling of the comprehensive dismantling processes; and regional as well as supra-regional public and political institutions are interested in estimates of changes to the installed wind energy capacity in order to enable optimal control of future capacity expansion under consideration of societal, economic and political aspects.

dismantling, wind turbine

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