Current Projects

The developments of recent years in the field of digitalisation bring with them great potential for employees in the areas of production and logistics. Their acceptance and the success of their use is closely linked to the existing qualifications and competences of the employees.
The Production Technology Group primarily focuses on the change processes that are triggered by the use of assistance systems and production planning systems in the manufacturing industry and evaluates the need for qualifications that has arisen. In addition to the advisory services, which are available to the companies as an auxiliary tool for coping with the new challenge, the group is developing a teaching concept tailored to the needs of the target group.

Within the project, the Production Technology Group at the TU Ilmenau is addressing the integration of the application scenario of fixture-free laser beam welding. For this purpose, displacements that occur during fixture-free welding are to be recorded, estimated and corresponding countermeasures derived in order to adapt the process to the position of the components. Based on the use of real-time capable process analytics, the resulting displacements are to be characterised using suitable deep-learning methods, the time sequence of the gap change predicted and a necessary position change calculated and implemented. The project specifically addresses the application of robot-supported welding scenarios in order to ensure a high degree of feasibility in the industrial application field and to be able to demonstrate the holistic mapping of the developed engineering methods when using learning-based assistance systems.

In this research project, the Production Technology Group at the TU Ilmenau is addressing the laser welding of galvanised steels. The existing challenge, which is particularly prevalent in fusion welding processes, lies in the low evaporation temperature of the zinc layer. At 906°C, this is far below the melting temperature of the steel and thus causes weld defects in the form of spatter and pore formation during laser beam deep penetration welding. The Production Technology Group is pursuing the approach of adapted rotationally symmetrical intensity distributions in order to influence the vapour capillary and the melt pool and thus realise a significant reduction in weld defects. The industrial application of core-ring intensities has been state of the art in this context for several years. However, the specially generated intensity images are largely geometrically unchangeable. This is where the research project comes in and pursues the goal of adjusting the diameters of the core and ring images independently of each other with the help of a special optical structure. The Production Technology Group is supported by the Department of Technical Optics at the Ilmenau University of Technology in the development of the optical structure.  In addition to deep-drawing steels and high-strength steels, the project is also investigating different types and thicknesses of coatings.  Thus, for different welding tasks (sheet thickness, coating, etc.), suitable ratios of core to ring diameter with the corresponding performances are to be found and serve as a guideline for manufacturers of fibre optic cables that can produce such intensity images.

The use of high-alloy steels is essential in numerous industries, including the chemical and automotive industries. For the production of industry-specific products, laser beam welding is widely used industrially due to its process advantages, but process-related seam imperfections such as spatter formation occur at high welding speeds ≥8m/min. This limits the economic potential. In contrast, the currently available power reserves of new solid-state lasers cannot be converted into an increase in welding speed, or only with complex adaptation of the process control. The aim of the project is to develop strategies and procedures that significantly reduce the occurrence of seam imperfections in the laser beam welding of high-alloy steels at high welding speeds (≥8m/min) on the basis of local gas flows. The approach adopted is based on the fact that the additional dynamic pressure exerted by the gas flow positively influences the internal capillary pressure balance from capillary-closing to capillary-opening pressures without exerting any significant mechanical influence. The resulting increase in capillary stability significantly reduces seam imperfections. Compared to known solution approaches, such as beam oscillation or locally adapted intensity distributions, the approach pursued is not limited to specific welding regimes, welding depths or sheet thicknesses. The project provides the necessary scientific knowledge based on the interactions between process variables, gas supply and resulting seam quality, generalises these and links them with regard to industrial issues such as positional tolerances and gap influence. This results in a high industrial application potential as well as the possibility of cost-effective implementation, especially for SMEs.

The application of a self-propagating reaction as a heat source in joining processes aims at very high propagation speeds of the reaction front and associated short process times. However, a large number of applications require tailor-made temperature distributions during the joining process depending on heat conduction, heat capacity and density of the materials and the geometric shape in the joining zone from the components in order to realise weldability. 
In joining, especially in soldering, nanoscale reaction films with a high in-plane propagation speed are currently commonly used. However, the uniform layer design does not take into account the material and geometric peculiarities of the structures to be joined. For example, for joints between partners of different thicknesses or different morphologies, asymmetric or anisotropic heat flows must be considered during the joining process and in the design of the films. The characterisation of the interaction between process, film and microstructure is the central challenge in joining processes with reactive films in order to realise a tailor-made temperature-time curve for a large-area joint (> 20 x 20 mm²), a design of the films and a surface structure.
This project aims to develop an overall approach for the fabrication, characterisation and application of reactive films with tailored morphologies for macroscopic joining of thermoplastics and metals. With a combination of material, form and force locking in the joining zone, joints with improved load-bearing properties can be realised compared to joints currently produced with nanoscale reactive films.

The development of an innovative self-acting pressure-controlled check valve with a corresponding shut-off valve for a nominal pressure of up to 1,000 bar is planned for use in H2 filling stations, which has not yet been implemented on the market. A new combined additive manufacturing process for metallic components (wire-based WAAM and powder bed) is being developed for the production of the valve. This also enables an innovative design of the valve for improved flow. In this context, a material or a material mix is being developed that is intended to prevent or counteract embrittlement by H2 and also withstands temperatures in the range of 2 K to 673 K. The innovative valve is also to be equipped with sensors for the first time. The innovative valve is also to be equipped for the first time with sensors for condition monitoring and the data is to be evaluated by means of intelligent algorithms and used for corresponding maintenance purposes and safety analyses. The sensor technology is to be integrated into the manufacturing process. The energy for the integrated sensor technology is obtained from energy harvesting via the kinetic energy of the valve.

The aim of the project is to develop a quality-assured process to produce elements for art objects from high-alloy steel materials that meet the requirement of mirror polishing by means of arc welding. The aim is to produce complex raw parts for art objects individually and cost-effectively and to meet the requirements of polishing after milling. The newly developed process and the resulting design possibilities are intended to make the resulting raw parts for art objects easier to assemble, faster to manufacture by reducing the waiting time for ordering materials and the machining effort, and more cost-effective than before. In order to take the special features of additive manufacturing into account for the first time in distortion-free polishing, new procedures must be developed for surface preparation and the polishing process. These include aspects of both residual stress and low-distortion additively manufactured elements that are geometrically within the dimensional tolerances during subsequent machining and do not exhibit any distortion.

The IGF research project 20156 BR addresses highly productive joint welding by means of a metal inert gas welding process. On the one hand, the process is extended by feeding up to two hot wires (HD) into the molten pool of the MSG process. A two-dimensional deflection of the arc is ensured by a phase shift of the supplied wires, which leads, for example, to a positive influence on the solidification mechanisms of the molten pool. On the other hand, the two-dimensional deflection of the arc is realised by an additional magnetic field. Both approaches enable the adjustment of the thermal field in the welding zone as well as an increase of the deposition rate in the welding process. This leads to a highly productive and economical application of the MSG process, for example in the field of thick plate welding.

In construction, linear steel elements are often used in different spatial directions and relative positions, which are connected for load transfer by means of so-called steel construction nodes. Due to the individuality of structural designs for buildings, complex steel construction nodes are produced in low batch sizes and often as individual pieces. The design and manufacturing effort for these structures, which have to carry the highest loads, is very high and therefore expensive. The idea of the project is to use build-up welding as an additive manufacturing process to produce individual steel construction nodes economically and with quality assurance for the first time in the future. The focus is on the development of the manufacturing process with simultaneous development of secure inline quality assurance with feedback on the current printing process. In addition, there is a feedback to the topology optimisation, which is restricted by the process to be developed. The analysis of the relevant process factors, the development of the software, as well as the material-technical investigation and the integration into the process chain represent further challenges of the project.

The preservation, restoration and upgrading of historical buildings are summarised under the term revitalisation, which represents an enormous economic and technical challenge. In order to meet this challenge, a variety of customised solutions are required that use 3D building surveys and laser scanning, digital recording of building conditions, numerical simulation and additive manufacturing processes to validate methods and revitalisation strategies and provide concrete value-added chains for the trade.

The application fields of remote laser welding continue to increase due to the advantages in terms of positioning times, high welding speeds, optimised welding sequences and large working distances. However, an extension of the remote application to the welding of high-alloy steels, e.g. for household appliance technology, requires efficient protection of the weld metal from the oxygen-containing environment by shielding gases in order to ensure the material properties, in particular the corrosion protection.
This is where the research project comes in, with the aim of developing user-friendly design criteria by systematically investigating the complex system of shielding gas supply, flow, interference contour, laser beam process and environmental influence. The approach pursued is based on a systemic consideration along this flow path from the nozzle via the working area with the interactions in the laser beam process or the environment up to the interference contour. Experimental investigations enable the consideration of analogies of fluid mechanics as well as the methodical decomposition of the complex overall system.