Publications

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

3D printing of large mechanical engineering components with a unique character, such as ship gearbox housings, has great development potential as so-called additive manufacturing. As an alternative to casting with complex mold construction, additive manufacturing of such large products offers significantly greater design freedom. To this end, a consortium of research institutes and companies from Hanover, Langenhagen and Hamelin is jointly developing an XXL 3D printer with an installation space of 4.5 m * 3 m * 1.4 m. The printer will be used for the production of large parts.

Additive Manufacturing, 3D printing, XXL-products, Production of unique pieces, quality control

This article is about building recycling loops for 3D printing. For this purpose, scientists at the Institute for Integrated Production Hannover (IPH) gGmbH are researching process steps for the extraction and processing of recycled plastic materials.

recycling, additive manufacturing, plastic waste

The production of hybrid components involves a long process chain, which leads to high investment costs even before machining. To increase process safety and process quality during finishing, it is necessary to provide information about the semi-finished parts geometry for the machining process and to identify defect components at an early stage. This paper presents an investigation to predict variations in dimension and cavities inside the material during cross-wedge rolling of shafts based on measured tool pressure. First, the process is investigated with respect to the variation in diameter for three roll gaps and two materials. Subsequently, features are generated from the hydraulic pressures of the tools and multi-linear regression models are developed in order to determine the resulting diameters of the shaft shoulder. These models show bet-ter prediction accuracy than models based on meta-data about set roll gap and formed material. The features are additionally used to successfully monitor the process with regard to the Mannesmann effect. Finally, a sensor concept for a new cross-wedge rolling machine to improve the prediction of the workpiece geometry and a new approach for monitoring machining processes of workpieces with dimensional variations are presented for upcoming studies.

Cross-Wedge Rolling, Forming, hybrid, tailored forming

Warm forged components have better surface properties and higher dimensional accuracy than hot forged components. Diamond-like-carbon (DLC) coatings can be used as wear protection coatings, which are anti-adhesive and extremely hard (up to 3500 HV), to increase tool service life. In the first funding period of the research project at the IPH – Institut für Integrierte Produktion Hannover gGmbH and the Institute for Surface Technology (IOT) of the Technical University of Braunschweig in cooperation with the Fraunhofer Institute for Surface Engineering and Thin Films (IST), the influence of different coating types and process temperatures on tool wear was investigated. The result is, that DLC coatings can reduce tool wear in some cases significantly, but that their service life is strongly dependent on the temperature. Coating-integrated temperature measurement could not be realised at that point, due to adhesion challenges. During the second funding period, the effect of multilayer DLC coatings on tool wear was investigated. Also, an additional method of the temperature measurement on the engraving surface using thin film sensors was developed in order to correlate the local process temperature and local layer wear. In this work, the development of and the results gathered by the thin film temperature sensors are presented, which enable for more accurate temperature measurements than commonly used thermocouples. Their functionality and durability under high loads were investigated and showed to be promising.

DLC2, warm forging, forging, wear, forming

Factory planning is an important tool for
manufacturing companies to raise their efficiency and to
maintain their competitiveness by changing market or
customer requirements. A special challenge is the acquisition
of layout data and the processing of this data in suitable
planning tools. Current approaches still measure manually
or have to transfer acquired data from laser scanners by
hand into planning tools, which leads to a high effort and
error proneness.
This paper presents a holistic concept for automated
and systematic data acquisition and processing for factory
planning processes.

3D factory planning, automated drone flight, point cloud processing, 3D layout scan

How can additive process chains be automated and print quality monitored? How is a component made of metal and plastic created in multi-material printing? Scientists from Lower Saxony ADDITIV have been researching this and more in the past three years.

additive manufacturing, 3d printing, automation, quality assurance

In this article, a method for automatic visual obstruction detection and masktype congruent visual obstruction compensation, based on the principal of augmented reality, is presented. The method is based on the superposition of a simulated operator’s field of view with information from a scene reconstructed by two RGB-Cameras. These cameras are arranged in a way that they can record the scene information be-hind the view restriction. Besides the presentation of the test rig, a detailed presentation of the image pro-cessing software is given. With a view to the later use of the system in a forklift truck, the real-time capa-bility of the system will be tested and optimization possibilities will be discussed.

augmented reality, driver assistance system, forklift trucks, image processing, obstacle detection

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