Publications

As a result of the increasing feed-in of renewable energies, the volatility of the electricity price rises. Considering this, manufacturers can save energy costs by applying an energy price-oriented sequencing rule. Since the application of this sequencing rule does not only have an impact on the energy costs, a potential analysis is presented in this article which, in addition to the energy costs, also considers the schedule compliance cost of production orders.

cost accounting, manufacturing control, production planning and control

In production, product-related error costs can be reduced by focusing on human production factors, such as considering human performance fluctuations during the day, when production planning with respect to job-shop scheduling. In this article, the flexible job-shop scheduling problem is extended by considering product-related error costs and logistic costs. Product-related error costs are increased by over stressing the operative workers. Logistic costs are based on work in process and throughput time. This cost-based definition enables a production plan to be simultaneously optimized in respect of both error and logistic costs. The product-related error costs and flexible job-shop scheduling problem are described mathematically and a memetic algorithm is also presented as an approach. Within the memetic algorithm, the evolutionary process is supplemented with a local search procedure to improve the ability of solutions and repair procedures to rectify infeasible solutions. The influence of product-related error costs on the total costs of a production plan within job-shop scheduling is presented.

flexible job shop scheduling, memetic algorithm, human perfor-mance fluctuation, error costs

An essential component of belt conveyor systems are the support idlers. Particularly in bulk material handling systems, which are used in demanding terrain with numerous gradients as well as under extreme environmental conditions in tropical and arctic regions, they are exposed to considerable stress. The steadily growing flow rates mean higher loads and speeds for the support idlers. This trend is countered by new drive concepts. For example, belt-driven conveyor systems with internally installed motors are used.

Within a research project, the IPH is developing a dual measuring system that can be used to test both conventional bearing rollers and driven bearing rollers.

driven idlers, test rig, efficiency of conveying systems

In respect to the expansion of renewable energies, temporary oversupplies of electrical energy cause a resulting price decline on the German electricity exchange. The electricity traded on the electricity exchange already shows high price volatility. For this reason, energy storage systems are needed that can balance energy supply and demand to ensure grid stability. The production industry can make a contribution by adjusting its consumption by shifting energy-intensive production steps to times of negative residual load.

energy cost, production planning, requirements, power

The measurement of torque via sensors as well as the generation of torque form the basis of many industrial sectors. Within a research project an optical and non-contact measurement method to detect the absolute rotation angle and torque was developed. For comparison with the current state of the art torque sensors a test stand was built and compared to a reference torque sensor. The results of this validation are presented in the present paper.

torque, rotation angle, optical, validation

The production and logistics divisions are currently under pressure mainly due to the increasing demand for product variability. Interactive assistance systems make an essential contribution to increasing efficiency in these areas. However, SMEs are critically opposed to the introduction of technology because of the lack of general conditions, since this is not a trivial one. If a company plans the implementation of interactive assistance systems in production and logistics, maturity models are suitable for capability analysis and support in the planning and control of this process. However, it is important to follow a systematic process for the development of the models, in order to ensure a successful implementation of the assistance systems in the company. 

industry 4.0, digitization, interactive assistance systems, data glasses, maturity models

Develop new ideas away from the desk: This is made possible by the creative space at the Institut für Integrierte Produktion Hannover (IPH) gGmbH. The retreat is intended to stimulate reflection and creativity, but also to facilitate teamwork.

creative space

The investigation of thin flash generation in a precision forging process of an aluminum long part using finite elements analysis (FEA) and corresponding forging trials is described in the presentation. Thin flash generation leads to bad handling and positioning in subsequent process steps and therefore tolerance defects. For investigation purpose, the forging processes were varied by use of different preforms with equal volumes but different mass distributions, while the geometrical parameters of the final part were not varied. 

The forging processes were analyzed by FEA with focus on the value of the form-filling simultaneity depending on the preform geometry. Afterwards, corresponding forging trials were carried out for validation.The results of the experiments and the FEA showed good agreement concerning the part areas were thin flash generation was predicted by FEA and actually occurred in experiments.Preforms with higher values of form-filling simultaneity showed less thin flash generation while preforms with lower values of form-filling simultaneity showed significantly increased thin flash generation.

forging, flashless forging, aluminum, FEA, thin flash, prediction

To be able to forge undercut parts there is a need for an appropriate multidirectional forging tool. The main issue is the high required clamp force the tool must endure. Therefore two versions of the tool were designed. They differ in the closing mechanism for upper and lower die: one is form-fit, the other one is force-fit. An analyzation reveals that the force-fit version is more advantageous.

tool, design, forging, undercut, multidirectional

The generation of bulk metal forming processes needs a lot of time. Researchers construct and simulate many days until a forming sequence without defects is found. At IPH a algorithm is supposed to predict a simulation result within one minute based on the constructions made. The basis for the prediction are many simulations, which were set up, executed and analysed automatically. This article decribes one possible way of doing so.

KImulation, simulation, automation

Work-related illnesses and their results may pose a threat to businesses' productivity. This may as well affect businesses' competitiveness for the worse. A workplace designed by methods of ergonomic workplace-design may counter some of the caused issues. But companies often lack knowledge or fear required financial resources to restructure workplaces. With this article technical requirements to an automated ergonomics assesment system are described.

ergonomics, evaluation, optimization, workplace design

Marine gearboxes ensure the reliability of the entire ship. Therefore a timely maintenance is crucial. To decrease maintenance costs and increase security, IPH develops a wireless and energy-autonomous measurement system to monitor marine gearboxes from afar.

gearbox, ship, condition monitoring, maintenance

In order to improve the overall efficiency of production facilities through the use of automated guided vehicle systems (AGVs), the availability of the AGVs has to be high. Failures of AGVs have to be minimized. However, if a failure occurs, a successful disturbance management is crucial. Especially for producing companies, economic losses can occur, if material is not at the right place at the right time. Delays can be a hazard to the adherence to delivery dates. In this research project, a support system is developed that automatically generates strategies for the handling of disturbances.

AGV, expert system, automated guided vehicles, case-based reasoning, CBR

In the automotive industry, aluminum forged parts must fulfill lightweight and heavy duty performance requirements. The generation of thin flash between die halves and in the small gaps between the die and punch must be prevented during the flashless forging process in completely enclosed dies. However, thin flash formation is neither predictable nor preventable.

A numerical model is developed based on finite element analysis to investigate and predict the generation of thin flash in aluminum flashless precision forging processes. The significance and effects of the main influencing input parameters, including billet temperature, forming velocity, and width of gap, on different resulting parameters are evaluated. Among all resulting parameters in the established numerical model, hydrostatic pressure and the forming force in the main forming direction have been identified as the most suitable for predicting thin flash generation.

aluminum forging, forging in completely enclosed dies, flashless forging, FEA

Wind turbines can withstand more load changes than bridges or helicopters - but at some point they, too, have had their day. Operators of wind turbines should therefore consider their options for continued operation, repowering or complete dismantling before the end of the approved operating period. Together with practical partners, the Institut für Integrierte Produktion Hannover (IPH) gGmbH is researching how dismantling can be carried out quickly, cost-effectively and in an environmentally friendly manner. The project "Development of an impact model for the efficient design of dismantling networks for XXL products" is funded by the German Research Foundation (DFG).

dismantling, wind turbine

A combined measurement method for the optical determination of the absolute rotational angle and torque was realized. Absolute codings of the angle as well as proper production technologies for the production of suitable markings on the shaft were investigated and successfully implemented.

The absolute rotational angle could be measured with a resolution of about 0.001° at an accuracy of better than 0.2° (corresponds to 0.05% f. s.). Torque was determined with an accuracy of about 3% f. s..

The conclusion is that the overall aim was achieved.

optical measurement, torque, absolute angle of rotation

This lecture discusses the results of the research project "4.0 Ready", and goes into detail about the potentials and barriers of the implementation of interactive assistance systems, especially in the service and maintenance, as well as the support of the implementation by the use of maturity models.

industry 4.0, interactive assistance systems, data glasses, maturity models

Men and machines will soon be working side by side. Researchers at IPH contribute to this trend: They have developed a driverless forklift truck which understands human language and gestures.

Industry 4.0, logistics, autonomous transportation, AGV

High temperatures up to 1280 °C and high pressures during the forming opperation lead to strong tool wear in forging processes. Increasing tool wear can lead to very high costs. By experiments conducted at the Institut für Integrierte Produktion in Hanover the correlation between tool wear and lot size in hot forging processes was verfied. The findings will help companies to optimise maintenance procedures and therefore reduce cost in the future.

forging, steel, tool wear, lot size

A bus rebuilt as factory is presently touring across Lower Saxony and Bremen. The goal: getting small enterprises informed on Industry 4.0. The free roadshows are organized by "Mit uns digital!". Until the end of 2017, there will be another eleven tours.

industry 4.0, digitalization, SMEs

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