Publications

Flat die rolling is a solid forming operation, in which two engraved tool plates run past each other and thereby form a cylindrical semi-finished product. The non-circular rolling can be used as a preform optimising process, where it should be possible to form local non-circular sections, for example ellipses or eccentrics, into a cylindrical semi-finished product. The material flow should be exclusively in radial direction. Initial simulations show that the requirements can be met.

non-circular rolling, cross wedge rolling, flat dies, preforms and intermediate forms, FEM

The development of a method for the optimal planning of the relocation of factory objects is being addressed by the IPH - Institut für Integrierte Produktion Hannover gGmbH within the framework of a research project. The design of a relocation plan, taking into account temporal and spatial restrictions, represents a complex planning problem. The method to be developed enables a comprehensive evaluation of a relocation plan with regard to different target criteria. The mathematical optimisation model is to be implemented with the help of a heuristic solution procedure. The intuitive implementation within a software environment further supports the easy applicability.

Factory Planning, Relocation, Project Scheduling, Preparation for Realisation, Operations Research

Since free?aces for new buildings are limited or not available at all, redensification is a promising approach to generate new living space. This can be both the extension of existing buildings by further storeys and the vertical extension or change of use of other building structures. Modular house construction takes this objective into account because a large part of the added value is generated before construction begins. Its advantages are now set against the logistical challenges of post-densification.

Modular house construction, post-densification, construction sites, production planning and control

On inner-city construction sites, there is usually only a limited amount of space available. This increases the complexity in the implementation of corresponding construction projects and at the same time the risk of postponements. Both the composition of the demand for specific types of space and the development of demand during the construction period should be taken into account in the course of scheduling. One way of assessing the demand for space is to introduce the potential for conversion as an indicator of the property of a specific space to be able to adapt flexibly in the event of possible short-term changes in the construction project. This can be used to create an evaluation basis that initially provides decision support for project planners and can subsequently be integrated into optimising procedures for scheduling. This will have a positive influence on the quality of a schedule in connection with its robustness.

Scheduling, construction management, project planning, production planning, construction sites

Multi-stage forging process chains are often used for the efficient production of complex geometries. Typically, these consist of homogeneous heating, one or more preform stages, and the final forging step. By inhomogeneously heated billets, the process chains can be simplified or shortened. This shall be achieved by setting various temperature fields within a billet, resulting in different yield stresses. These can influence the material flow, leading to easier production of complex parts. In this study, the influence of inhomogeneously heated billets on the forming process is investigated by means of FEA. For this purpose, two process chains including inhomogeneous heating and three homogeneously heated reference process chains are developed and compared. Each process chain is optimized until form filling and no defects occur. Target figures for the assessment are necessary forming force, the amount of material necessary to achieve form filling and die abrasion wear. For process chains with inhomogeneously heated billets, the results showed a small time window of about 5 s for a successful forming in terms of form filling. Forming forces and die abrasion wear increase for inhomogeneously heated billets due to higher initial flow stresses. However, the flash ratio decreases when billets are heated inhomogeneously. Depending on their size, inhomogeneously heated billets show up to 11.8% less flash than homogeneously heated billets. This shows a potential for the use of inhomogeneous heating to make forging processes more efficient. Subsequently, experimental tests will be carried out to verify the results of the simulations.

Inhomogeneous heating, Forging, FEA, Resource efficiency, Preform operation

To increase the economic efficiency in the production of geometrically complicated forgings, material efficiency is a determining factor. In this study, a method is being validated to automatically design a multi-staged forging sequence initially based on the CAD file of the forging. The method is intended to generate material-efficient forging sequences and reduce development time and dependence on reference processes in the design of forging sequences. Artificial neural networks are used to analyze the geometry of the forging and classify it into a shape class. Result of the analysis is information on component characteristics, such as bending and holes. From this, special operations such as a bending process in the forging sequence can be derived. A slicer algorithm is used to divide the CAD file of the forging into cutting planes and calculate the mass distribution around the center of gravity line of the forging. An algorithm approaches the mass distribution and cross-sectional contour step by step from the forging to the semi-finished product. Each intermediate form is exported as a CAD file. The algorithm takes less than 10 min to design a four-stage forging sequence. The designed forging sequences are checked by FE simulations. Quality criteria that are evaluated and investigated are form filling and folds. First FE simulations show that the automatically generated forging sequences allow the production of different forgings. In an iterative adaptation process, the results of the FE simulations are used to adjust the method to ensure material-efficient and process-reliable forging sequences.

Automatic process design, Forging, FEA, Resource efficiency, CAD

A method is presented that enables the complexity of a forging to be determined automatically on the basis of the CAD file of the forging. An automated evaluation of the forging complexity is necessary for a digitized and automated design of stage sequences in order to be able to determine important design parameters such as the flash ratio or the number of stages.

CAD, forming technology, algorithms

In the production of stock goods, manufacturing companies are faced with uncertain customer demand. In order to counter uncertainties, an increased inventory is necessary in order to be able to meet customer demand. The costs incurred are influenced by the ordering behaviour given the forecast uncertainty. Ordering behaviour is largely determined by the ordering policy. Therefore, the influence of forecast uncertainty and ordering policy on the resulting storage costs was investigated by means of sensitivity analyses. Accordingly, forecast uncertainties require larger inventories under the (t, S) policy than under the (s, q) policy.

stock planning, ordering policy, forecasting

Working on a real industrial project and getting professional practice in the process - students at Leibniz Universität Hannover have this opportunity in the "Cooperative Product Engineering" (KPE) project.

For more than 20 years, KPE has been offered as a semester project by Institut für Integrierte Produktion Hannover (IPH) gGmbH and Leibniz Universität Hannover. Students from the faculties of mechanical engineering and economics are given the opportunity here to apply their specialist knowledge from their studies in practice by working on a practical project for an industrial partner.

 

Student project

Unmanned aerial systems have changed the industry dramatically. The rapidly advancing technological development of so-called Unmanned Aircraft Systems (UAS) makes it necessary to address the design of future operational scenarios at an early stage.

UAS, Drones, Navigation

The compilation of information for the processing of internal production tasks is often based on less-questioned route sheet templates. The selection of the optimal amount and depth of information requires a positioning in an area of conflict between the amount of work in the planning process and the benefit in the execution. Therefore, a method to quantify and evaluate the level of detail of different information individually is presented. Thus a basis is created to determine the optimal level of detail in route sheets.

route sheets, work preparation, level of detail, provision of information, MES-implementation

How to compensate the restricted vision in forklifts with the help of strategically placed cameras and augmented reality glasses? Scientists from ITA and IPH are jointly tackling this question.

Augmented reality, AR, industrial trucks, vision enhancement, assistance system

Qualitative uncertainties are a key challenge for the further industrialization of additive manufacturing. To solve this challenge, methods for measuring the process states and properties of parts during additive manufacturing are essential. The subject of this review is in-situ process monitoring for material extrusion additive manufacturing. The objectives are, first, to quantify the research activity on this topic, second, to analyze the utilized technologies, and finally, to identify research gaps. Various databases were systematically searched for relevant publications and a total of 221 publications were analyzed in detail. The study demonstrated that the research activity in this field has been gaining importance. Numerous sensor technologies and analysis algorithms have been identified. Nonetheless, research gaps exist in topics such as optimized monitoring systems for industrial material extrusion facilities, inspection capabilities for additional quality characteristics, and standardization aspects. This literature review is the first to address process monitoring for material extrusion using a systematic and comprehensive approach.

Material extrusion, Fused deposition modeling, Process monitoring, Sensor technology, Research gaps

Software for an Automated Multidimensional Factory Layout Optimisation: Layout planning is a complex planning task in the context of factory planning, which up to now has usually needed to be carried out manually. Although many optimisation methods for the underlying problem have been developed in the past, they were only applicable to a small group of experts, mostly from universities. Therefore, an easy-touse software for layout planning was developed in a research project to provide companies with access to these optimisation methods.

Factory planning, facility layout planning, optimization, operations research, software

In order to automate the order control of tooth replacement products, an AI model was developed that enables classification into different product classes. The individual tooth replacement products are available in STL files. A mixed-data approach was used for the AI model. The STL file is converted to an image file and passed to a CNN and in parallel, information such as volume and surface dimensions were extracted from the STL file and passed to a ANN. The output from the ANN and the CNN is then combined to produce the final classification of the tooth replacement product.

Automated order control, AI, ANN, image processing, CAD

A concept was developed for the digitization of business processes in a craft enterprise. By introducing a document management system, the functional scope of the ERP system already in use was expanded and the business processes were converted to a paperless office. In addition, a concept for a digital construction file was developed in order to integrate employees in the field into digitized processes.

 

DMS, ERP, digitization, business processes, paperless office, trade

The machine learning based method for layout optimization of smallscale modular conveyor systems, which is developed within a research project at IPH – Institut für Integrierte Produktion Hannover gGmbH, provides SMEs a decision support, which enables them to execute complex layout planning independently. In addition, the machine learning method is intended to reduce the cost and time required for planning and to improve the quality of the solution compared to manual layout design.

Small-scale modular conveyors, conveyor systems, machine learning, artificial intelligence

Unmanned Aircraft Systems (UAS) cover a wide range of applications not only outdoors but also indoors. The use of UAS has already been successfully tested and validated in some of these application areas, such as factory layout digitization or in-plant material transport. The current state of technical development of UAS for flight control, collision avoidance and flight performance basically allows their use in production operations. It is still unclear which legal and thus also insurance-related, technical and operational prerequisites must be created by applying companies for the use in production operations. This white paper discusses these issues. A technical and operational risk analysis is then presented, which is supplemented by a catalog of measures for the proper introduction and use of UAS technology. Potential risks are considered, even though the risks can be reduced by safety mechanisms and appropriate sensor technology as the degree of automation of UAS increases.

Drones, intralogistics, automated transport

Maturity-based Evaluation of Requirements for a Successful MES Implementation. The use of a Manufacturing Execution System (MES) can offer many advantages for companies, but the implementation often poses a great challenge. The determination of necessary requirements, their fulfilment by the company and their consideration in the implementation process are decisive for a successful implementation. In the following article, the development of a maturity-based method for the evaluation and improvement of the companyspecific fulfilment of the requirements of an MES implementation is presented.

Manufacturing Execution System, Maturity Model, Digitalization

In cooperation with Otto Fuchs KG, IPH is researching methods to predict and avoid thin flash during flashless forging of aluminum. The development of target-oriented sealing concepts should significantly increase process efficiency in the future.

flashless forging, aluminum, thin flash, sealing concept

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