Publications

This paper describes the development and prototypical implementation of an energy self-sufficient sensor for condition monitoring of wet-running steel disc clutches in marine gearboxes. For the precise control of an automated system and the monitoring of its performance, the knowledge about the possible wear is an essential prerequisite. In addition, the storage of sensor data over the life of the system offers the possibility of long-term condition monitoring. The combination with various other technological components creates a solution that enables cost-effective condition monitoring of marine gearboxes. Compared to existing systems, for example, the costs for installation and maintenance are significantly reduced. Both the methodology from the morphological box to the fine concept as well as the first measurements of the sensors are presented.

automated system, condition monitoring, metrology, clutch, gearbox

In average, more than 1,275 wind turbines were installed annually since 1997 in Germany and more than 27,000 wind turbines are in operation today. The technical and economic life time of wind turbines is around 20 to 25 years. Consequently, dismantling of aging wind turbines will increase significantly in upcoming years due to repowering or decommissioning of wind farms and lead to millions of costs for operators. An option to supersede the costly and time-consuming dismantling of wind turbines entirely on-site is to establish a dismantling network in which partly dismantled wind turbines are transported to specialized dismantling sites for further handling. This network requires an optimization model to determine optimal locations and an appropriate distribution of disassembly steps to dismantling sites. The challenge is to consider the networks dependency on the trade-off between transportation and dismantling costs which, in turn, depends on the selection of dismantling depths and sites. Building on the Koopmans-Beckmann problem, we present a mathematical optimization model to address the described location planning and allocation problem. To permit a proof-of-concept, we apply our model to a case-study of an exemplary wind farm in Northern Germany. Our results show that the model can assist dismantling companies to arrange efficient dismantling networks for wind turbines and to benefit from emerging economic advantages.

dismantling, wind turbine, optimization model

Structured factory planning is a key to ensure the competitiveness concerning to the increasing pressure from globalization and the high market dynamic. Companies though avoid to do factory planning projects, because of the high effort. For this reason, the processes of factory layout capture and factory layout assessment are in need of improvement in order to increase the efficiency, which will be achieved through new technologies and a semi automation of the processes.

factory planning, drone, photgrammetry, laserscan, image data processing

Black marking as micrometer scaled binary coding applied on shafts by ultrashort pulsed lasers with high contrast and without ablation as a non-contact sensor system for combined measurement of angular position and torque.

laser materials processing, sensors, absorption, image analysis

Constantly increasing quality requirements and ever-stricter conditions pose difficult challenges for the foundry industry. They must produce the high-quality components demanded by the market at a reasonable cost. Modern technologies and innovative methods help to master this challenge. Until recently, production, from the design of the aluminum melting furnace to daily process, relied largely on traditional methods and experience. However, important data and information about the melting process—for example, the temperatures and the shape of the aluminum block in the furnace—can hardly be obtained with conventional experimental methods, as the temperatures exceed 700 °C. Therefore, this research project investigates the method of monitoring a melting process by means of optical sensors for the first time. The purpose of this paper is to predict the surface shape of the block during the melting process, as it is not possible to maintain a constant monitoring due to the heat and energy loss during measurement (Einsatz einer Lichtfeldkamera im Hochtemperaturbereich beim Schmelzvorgang von Aluminium. To generate the necessary data, a 3D light-field camera is installed on top of an aluminum melting furnace in order to monitor the process. The basic idea is to find a general method for curve modeling from scattered range data on the aluminum surface in 3D space. By means of the (x, y, z) data from the 3D camera, the aluminum surface is modeled as a polynomial function with coefficient derived using various interpolation and approximation methods. This study presents an attempt to find the optimal polynomial function model that describes the aluminum surface during the melting process by interpolation or approximation methods. The best method for curve fitting will be extended and implemented for surface modeling. 

melting process light-field, polynomial function, interpolation, approximation, aluminum surface

Future factory planning projects are much easier and cheaper than today. With a drone it es possible to scan a factory layout during the flight in a short time. To achieve this benefits, researchers of the IPH are developing a new factory planning method.

drone, threedimensional factory layout, object recognition in point clouds, factory planning

Every year about two billion components are manufactured by forging. Because of the high temperatures and high forming forces required, many components are produced in a segmental manner and later joined together, e.g. by welding. In order to save manufacturing steps – and thus costs and time – a production process is to be developed in which elements of different steels are simultaneously deformed and joined in a single forging. These elements could have very different geometries and thus strongly influence the manufacturability of complex parts. This combination of deformation and joining is called a hybrid process.
In this paper, an investigation on the simultaneous forging and joining of massive bulk and sheet elements is described. The aim is to characterize a first influence of the different forming temperatures on the resulting joint zone of the hybrid process. For this purpose, a series of tests are carried out using a screw press. To find out if there is a correlation between the temperature and the quality of hybrid forgings, the samples are analyzed by means of tensile tests and metallographic analysis. These analyses show the influence of the forming temperature on the joint zone. Based on the knowledge gained, the joint zone can be characterized and evaluated. The main finding is that at higher forming temperatures, the areas of material bonding are significantly stronger than at low temperatures.
The findings obtained contribute to the development of joining by hybrid forging. The results can be used to further investigate the relevant manufacturing processes and component properties of hybrid parts.

forging, forming, hybrid process, massive element, sheet element

Currently used methods for factory layout planning are limited in their evaluation methods. Factory evaluation is either qualitative or quantitative, but limited to a few objectives. These deficits were overcome by the development of a quantitative, multidimensional ad hoc factory evaluation method. On this basis, it is now possible to develop a method for factory layout planning that reduces the planning effort and significantly increases the quality of the solution.

facility layout planning, factory planning, operations research, mathematical modelling

For companies it is challenging to identify application scenarios for Industry 4.0 as well as to use the associated potential. This article describes a strategy, which includes methodical and knowledge-based guidelines for decisions, to increase the likelihood of beneficial industry 4.0 transformations.

industry 4.0, strategy, production system

The measurement of the absolute rotational angle and torque via sensors forms the basis for many industrial sectors. Until now, combined sensors have not been available, so that a lot of installation space is occupied by sensor setups. In addition, the sensor setups get expensive quickly. Therefore, an optical and non-contact measurement method to detect the absolute angle of rotation and torque was developed. This paper presents the validation methodology, the setup of the test bench and the validation results. With an angular resolution of 0.001 degree and an accuracy of more than 0.05 percent, the results are promising. However, for industrial application further investigations on determining torque and miniaturizing the optical setup are required.

absolute angular position, angle difference, sensor, torque

Rising and increasingly volatile energy prices resulting from increased power feeds from renewable sources such as solar and wind energy are confronting manufacturers with new challenges. If these companies procure their power supplies at ?uctuating short-term prices from electricity exchanges or through energy purchasing pools, they can in?uence the result-ing energy costs through production control via its actuating variables while energy consumption remains constant. A form of sequencing that decides at short notice which order will be processed next shows particularly high potential. The energy price-oriented sequencing rule that is introduced in this article prioritises orders with a high energy requirement at times when energy prices are low and gives precedence to orders that require less energy at times when energy prices are high, without neglecting the scheduled completion deadline. However, this sequencing rule can only be applied e?ectively under certain preconditions. These are elaborated in this article by means of a simulation study that will con?rm the way the rule functions.

production planning and control, manufacturing control, sequencing, energy costs

In the forging industry, like in many other economic sectors, it is common to simulate forming processes before executing experimental trials. An iterative simulation process is more economic than trials only but still takes a lot of time. A simulation with realistic parameters takes many hours. For an economical production the idea of predicting some main results of the simulation by Data mining was developed. Within this paper, the use of four different Data mining methods for the prediction of certain characteristics of a simulated flange forging process are presented. The methods artificial neural network, support vector machine, linear regression and polynomial regression are used to predict forming forces and the lack of volume. Both are important parameters for a successful simulation of a forging process. Regarding both, forging forming forces and lack of volume after the simulation, it is revealed that an artificial neural network is the most suitable.

data mining, artificial neural network, linear and polynomial regression, support vector machine

Interactive assistance systems such as data glasses or headsets as a new human-machine interface enable an increase in process quality and speed through networking within the factory. However, small and medium-sized enterprises (SMEs) are critical to the implementation of these systems. Therefore, this article describes the development of a maturity model for a systematic ability analysis and increase to the implementation of interactive assistance.

industry 4.0, interactive assistance systems, maturity models, implementation support

This paper describes the production process of serially arranged hybrid steel parts, produced by combining a laser welding process with a subsequent cross wedge rolling process. The presented results are only a first approach in order to get first insights in the forming behaviour of laser welded and cross wedge rolled parts. The investigated material combination is C22 (1.0402) and 20MnCr5 (1.7147). This innovative process chain enables the production of hybrid parts. To evaluate the developed process chain, the weld and the joining zone is analysed before and after cross wedge rolling. Main results are that the joining process using laser welding enables a strong bonding between the two materials with a higher hardness in the joining zone than for the individual materials. After the forming process, the bonding of the joining zone is still present, while the hardness decreased but remains higher than of the materials themselves.

tailored forming, laser welding, hybrid parts, cross wedge rolling

The storage planning is an important component of the factory planning and describes an improvement potential in the times of an increasing global competition. The selection of a suitable storage, commissioning and transport system is a big challenge especially for small and medium-sized enterprises. In a research project of IPH – Institut für Integrierte Produktion Hannover a method for companies will be created to determine the necessary level of versatility and automation to choose an optimal system. This article introduces the research project and explains the approach and first results.

storage planning, sct systems, versatility, automation, software demonstrator

Energy requirements of belt conveyor systems are essentially determined by the necessary drive power, which is composed of the main drive and intermediate drives. The use of driven support rollers reduces the load on the conventional drive at the head of conveyor systems. Thus, the drive can be build smaller, which can lead to energy and cost savings. In contrast to conventional head drives, driven rollers enable the implementation of modular conveyor systems. The theoretical possibilities and consequences of driven rollers are promising. Due to a lack of knowledge regarding the economic efficiency and behavior under certain conditions, driven rollers have not yet been integrated into real operation. In order to investigate the behavior of driven rollers and to ensure the introduction into practice, test stands are indispensable. This paper presents the concept of driven rollers and, on this basis, the development of a test stand for investigating these rollers.

driven roller, test rig, belt conveyor, energy efficiency

To forge a flashless crankshaft within few steps and with low energy consumption innovative forging processes are necessary, such as cross wedge rolling and multi-directional forging. The direct combination of the two forming processes normally leads to flash at the bottom of the crankweb preform after the multi-directional forging. The reason for the flash generation is the rotation-symmetric cross wedge rolled billet, which is formed laterally to the main axis during multi-directional forging. In this paper, a parameter field in which flashless crankshaft preforms can be forged is presented. The parameters varied within the experimental research are the forming angle and the cross section area reduction at cross wedge rolling as well as the axis offset, the billet temperature and the forming velocity at the multi-directional forging. The limits of this flashless parameter field are shown in several diagrams. For a flashless combination of two forming process low values for all parameters such as a forming angle of 30°, a cross section area reduction of 30 %, and a billet temperature of 1050 °C are recommended. Furthermore, the intensity of the influence of the significant parameters are shown. The cross section area reduction thereby caused the highest range at flash generation with 0.4 mm.

multi-directional forging, cross wedge rolling, crankshaft, parameter study, flashless

The melting process in an aluminum melting furnace cannot be monitored by contact sensors, since the furnace is not accessible due to the high temperatures (more than 700 °C). Therefore, monitoring the melting process by means of optical sensors is investigated for the first time in this research project. This article deals with an innovative optical measuring system that is able to monitor the melting bridge despite the red-hot furnace walls. For this purpose, a light-field camera is installed on top an aluminum melting furnace in order to monitor the process and to control a targeted heat input into the melting furnace using a rotatable burner. The light-field camera used can capture a 3D point cloud with only one image. To achieve this, a separate field of lenses is placed between the image sensor and the main lens, projecting a virtual intermediate image onto the actual image sensor for further data processing. In addition, a self-developed image analysis program serves to monitor the height variation of the aluminum block and any melting rest on the melting bridge of the furnace.

Thus, the energy efficiency of the aluminum melting process could be increased by 15 % and the melting time reduced by almost 20 minutes by means of online monitoring.

light-field camera, process monitoring, image processing, melting process, energy efficiency

One aim of the research project "Networked cognitive production Systems (netkoPs)" was the development of the formal language Production Modeling Language (PML). The PML is to be understood as a digital twin of the product and the production system. At the beginning, useful potentials for PML from the current state of research as well as the aims of the research project netkoPs were derived. Afterwards, based on a requirement analysis, the required data fields for the PML were classified. In a next step, the PML, based on the AutomationML, was implemented. The potential benefits formulated in the context of netkoPs could finally be demonstrated in connection with the further research results. For example, a preliminary ProductPML can equipping the machine before the product arrives.

digital twin, ProductionML, decentralized control, material flow

Lot sizing is an important task of production planning and control: basis of lot sizes are order change costs and costs for storage. Models for lot sizing do not consider lot size dependent maintenance costs. However, for a forging company the tool wear is very important, because the tooling costs represent a major part in the production cost. In this article, the deter-ministic lot size model of Andler is extended with lot size dependent maintenance costs. For this purpose, the correlation between lot size and the tool wear is ?rst derived in order to develop a lot size dependent wear function. The linking of a lot size dependent wear function with maintenance costs results in a lot size dependent maintenance cost function, which can be integrated into existing lot size models with a customized total cost function. The validation of the extended lot size model consists of two parts. In the ?rst part, the functionality of the extended lot size model is validated. In the second part, a sensitivity analysis of the lot size is carried out with regard to lot size dependent costs and unit costs.

lot sizing, tool wear, forging industry, sensitivity analysis

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