Publications

In this work we present an application of the virtual element method (VEM) to a forming process of hybrid metallic structures by cross-wedge rolling. The modeling of that process is embedded in a thermomechanical framework undergoing large deformations. Since forming processes include mostly huge displacements within a plastic regime, the difficulty of an accurate numerical treatment arises. VEM illustrates a stable, robust and quadratic convergence rate under extreme loading conditions in many fields of numerical mechanics. Numerically, the forming process is achieved by assigning time-dependent boundary conditions instead of modeling the contact mechanics yielding to a simplified formulation. Based on the two metallic combinations of steel and aluminum, different material properties are considered in the simulations. The purpose of this contribution is to illustrate the effectiveness of such a non-contact macroscopic framework by employing suitable boundary conditions within a virtual element scheme. A comparison with the classical finite element method (FEM) is performed to demonstrate the efficiency of the chosen approach. The numerical examples proposed in this work stem out from the DFG Collaborative Research Centre (CRC) 1153 “Process chain for the production of hybrid high-performance components through tailored forming”.

simulation, FEM, bulk metal forming, tailiored forming

Hybrid compound forging of aluminum bulk parts and steel sheet metals is a combination of material lightweight design and structural lightweight design. During this process, an aluminum bulk part and a steel sheet metal are combined and formed simultaneously. A material joint is generated by deforming, using zinc as solder material. This prevents the generation of brittle intermetallic Fe-Al-Phases as well as contact corrosion. The zinc layer is applied to the aluminum bulk part by hot dipping. To create a material locking connection by forming, suitable parameters such as the forming temperature are identified in first experimental trials. Microsections showed that the zinc layer is still intact after forming. In this paper the investigation of the effects of different steps of forming and different geometries of the aluminum bulk part surface on the joint strength are described. The forming tests show that a further forming of the aluminum part, resulting in a bigger deformation, leads to a stronger connection between both joining partners. But there is a limit to the forming since the applied forces can transfer to the steel sheet leading to an unintended deformation. The generated hybrid parts are tested for their ability for further forming. Therefore, the joined hybrid parts are undertaken a deep drawing process to see if the joint withstands further forming of the hybrid part.

aluminium, hybrid forging, lightweight construction, hybrid

Handling hot steel parts weighing several kilos is physically demanding. A new type of forging tongs is designed to reduce stress at work, prevent pain and reduce sick leave.                             

forging, ergonomic, stress reduction

The selection of storage, commissioning and transport systems (sct systems) is very complex due to the large number of available systems on the market and influencing factors. One important influencing factor is automation. To classify the degrees of automation of sct systems and to determine the individually required automation a method is proposed below.

automation, storage, commissioning and transport systems

Upfront investment costs for the tooling of injection molds are the basis for deciding if a mold is tooled and hence if a part is viable for mass-production. If tooling costs are too high, a product may not viable for production. If tooling costs are estimated too low by the tool shop, contract implications may arise.
The goal of this research is to develop a method with humanlike quotation accuracy, achieve standardization, factor in historic quotation data and shorten quotation process times. The machine learning approach developed is based on geometry data of parts and additional meta-information.

injection molding, tooling, industry 4.0

The aim of subproject B1 of the Collaborative Research Center (CRC) 1153 is to determine the formability of novel hybrid semi-finished products by means of incremental forming cross wedge rolling. Main aspect is the forming of hybrid semi-finished products made of steel, aluminium and hard material alloys. In order to reduce the component weight, the use of hybrid semi-finished products makes it possible to manufacture less stressed segments of a previously monolithic component from a light metal. To increase wear resistance, a component area (e.g. a bearing seat) can be coated with a hard material. In addition, process variables (e.g. temperature and force) are to be measured in contact between work piece and tool in the future. There are primarily two material arrangements for the semi-finished products used: coated (coaxial - demonstrator shaft 1) and joined at the front (serial - demonstrator shaft 3). One challenge is the heating of the semi-finished products necessary for forming, since the hybrid semi-finished product has different flow resistances due to the different materials and may have to be heated inhomogeneously in order to enable uniform forming.

cross-wedge rolling, forming, hybrid work pieces, tailored forming, hybrid semi-finished products

The Collaborative Research Centre 1153 (CRC 1153) “Process chain for the production of hybrid high-performance components through tailored forming“ at the Institute for Integrated Production in Hanover/Germany is opening up further potential for hybrid solid components. On the basis of a new type of production process, tailored semi-finished products already joined prior to forming are to be used.

tailored forming, cross-wedge rolling, forming, aluminium, steel

Quality assurance methods are a central success factor for the further industrialization of additive manufacturing. This paper presents an approach for an optical inspection system that controls the quality of additive material extrusion layer by layer. The inspection task gets analyzed, hardware components for data acquisition are designed and a first step towards texture-analytical detection of defects is presented.

additive manufacturing, 3d printing, material extrusion, fused deposition modeling, image processing

How ergonomic is my workplace? Scientists from Hanover have developed evaluation software that can answer this question quickly and objectively. The digital ergonomics evaluator is particularly helpful for small and medium-sized companies: In the future, they will be able to carry out ergonomics assessments without much effort to protect their assembly workers from back and knee pain, tendonitis or similar problems.

ergonomical assessment, industry 4.0, 3D camera

Thanks to digital assistants, even low-skilled workers can perform complex tasks - the example of SCHUBS GmbH shows this. The company manufactures customized control cabinets and is an important employer for people with disabilities. Schubs would like to introduce a digital assistance system so that they can take on more responsible tasks in the future. The Mittelstand 4.0 Competence Center Hanover developed the demonstrator for this.

assistance systems, digitization

The digitization of processes and the networking of systems is a major challenge for many small businesses. In addition to traditional production companies, the transition to Industry 4.0 is increasingly affecting branches that have not been adequately considered as users for smart technologies and IoT. Modern horse stables manage complex feed schedules, track movement data, analyze temperatures and other parameters or monitor electric fences. So far, there is no instrument to control all of these demanding and complex processes efficiently and easily. Ludwig und Partner Reitanlagen and the Mittelstand 4.0 competence center in Hanover worked together to develop a concept for the low-threshold networking of such facilities. This is intended to make digitization opportunities more accessible and to ensure economic operation.

digitization, Internet of Things, IoT, networking, retrofit

Whether transporting salt, sugar or any other bulk material, belt conveyors are ideal for achieving a continuous mass flow. Important components of belt conveyors are idlers. These support the belt and the bulk material on it. The Institut für Integrierte Produktion Hannover (IPH) has developed a test rig for the examination of idlers.

idlers, rollers, bulk material handling

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

A product-dependent, individual process development represents a main cost driver in laser material processing. Therefore, the expert system SmQL is being developed in an FQS-funded project, in which process knowledge can be stored in a formalized form and represented in rule form. This is intended to minimize times for setup processes and secure knowledge in the company in the long term.

expert system, industry 4.0, laser materials processing

Quality assurance methods are a central success factor for the further industrialization of additive manufacturing. In the IGF research project "Optical quality inspection for extrusion 3D printing (Quali3D)", a testing system is therefore being developed which monitors the quality of the additive process layer by layer. This should enable a comprehensive evaluation.

3D printing, additive manufacturing, optical metrology, image processing

The processing of ceramics is an important technology for various technical applications. In this paper, a highly
controllable process consisting of spray-coating and laser structuring to design ceramic layers on a versatile
applicable substrate is presented. A thermoelectric oxide, Ca3Co4O9, which is a type of thermoelectric material,
is used in the process and applied to a flexible ceramic substrate. The resulting structures have highly controllable
shapes and good thermoelectric properties, and they can be used to produce a printable thermoelectric
generator (TEG). The use of a flexible ceramic substrate and the high feasibility of the process lead to a universally
applicable procedure that can be used to process ceramics with unique structures and designs.

thermoelectric, printed electronic, laser structuring, printed ceramics, spray coating

This paper presents a method for the automated classification of forged parts for classification into the Spies order of shapes by artificial neural networks. The aim is to develop a recognition program within the framework of automated forging sequence planning, which can directly identify a shape class from the CAD file of the forged part and characteristics of the forged part relevant for the design of the process.

forging, ANN,CAD

The structured and future-orientated planning of factory layouts is an important factor in maintaining the competitive ability. However, conventional planning methods with 2D Layouts reach their limits because they can no longer map the increasingly complex factory structures in detail. Alternatives are offered by 360° environmental scanning methods, which currently only serve as a template for postmodeling. This article presents a method for planning directly in the factory image. The aim is to make the factory planning process more effective and less error-prone.

3D-factory layout, factory planning, production planning, point cloud, point cloud processing

Within the CoMoGear project, an energy self-sufficient wireless sensor network for the condition monitoring of highly stressed rotating components in marine gearboxes was developed. This sensor network consists of several sensor nodes and energy harvesters.

sensor nodes, condition monitoring, marine gearbox, energy harvesting

This article shows how the abilities known to humans to be flexible and adapt to changing environmental conditions, which are reflected in human cognitive characteristics, can be transferred to industrial trucks in intralogistics. As examples for the implementation of Industry 4.0 in intralogistics, technologies are presented that enable industrial trucks to recognize their environment, communicate information, draw conclusions, act autonomously, make decisions, learn or plan. These capabilities will be realized by an optical positioning system for position determination, camera-based storage/retrieval support and sensor technology integrated into tires, as well as novel forms of interaction for industrial trucks in the form of speech and gestures.

automated guided vehicle, augmented reality, smart glasses

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