We look forward to showcasing a wide range of exhibits on various topics at our booth at the Hannover Messe.
Maintaining competitiveness in manufacturing companies requires the continuous improvement of component specifications and/or alternative, more cost-efficient process chains for production and recycling management. As an alternative manufacturing process, a modified variant of laser cladding, extreme high-speed laser cladding (EHLA), could increase the coating efficiency for wear and corrosion protection of rotationally symmetrical components many times over, as the process allows high feed rates (> 20 m/min) and the processing of difficult-to-weld materials. The Fraunhofer ILT has transferred the initially 2D rotationally symmetrical process to processing in 3 dimensions for additive manufacturing, free-form surface coating and repair. In addition to the possibility of processing non-rotationally symmetrical components, the EHLA process in 3 dimensions, EHLA3D, enables the combination of high application rates and high structural resolutions. Thanks to the precise, controlled heat input, thin-walled structures with wall thicknesses d < 1 mm as well as solid volumes can be additively manufactured crack-free and with relative densities of over 99.5% with high productivity using EHLA3D. These process specifications allow the flexible design of thin-walled lightweight components made from difficult-to-weld aluminium alloys, for example. In the case of the exhibit, an aluminium flange was built individually with variable overhang geometries and a build time of < 1 h using EHLA3D. The process-specific advantages of the EHLA3D process are the construction of thin-walled elements, the processability of difficult-to-weld materials and near-net-shape additive manufacturing. Depending on the choice of material, these advantages allow component specifications and process specifications that can open up new fields of application in the industrial environment. Examples of the expansion of the application possibilities of EHLA3D to other fields of application include
Over the last two decades, the technical development of wind turbines in Germany has focussed on the construction of ever larger turbines. By increasing the hub height, the energy yield can be continuously increased. The average rotor diameter of wind turbines has almost doubled in the last five years. This development places high demands on the bearings used in wind turbine gearboxes - particularly with regard to weight, installation space and torque density. In order to meet these requirements, it is essential to switch from rolling bearings to hydrodynamic plain bearings.
Additive manufacturing processes enable the particularly energy- and material-efficient production of plain bearings on planetary gear bolts and the application of sensors to these components for condition monitoring. Using EHLA, metallic materials such as plain bearing bronzes (here: CuSn12Ni) and white metals can be applied as a material-locking coating. The optional simultaneous machining by SMaC (Simultaneous Machining and Coating), in which the planetary gear pin is simultaneously coated and mechanically reworked, enables even more economical production in a drastically shortened process chain. Using additive thin-film processes, such plain bearings can then be fitted with sensors that can detect torque, strain and structure-borne noise during use.
The combination of laser cladding processes with digital printing and laser post-treatment processes in one process chain enables the production of "sensing" components. This enables permanent monitoring for load documentation and overload detection. The integrated manufacturing process of component and sensor opens up new applications where condition monitoring was previously too complex or uneconomical. EHLA enables the economical and resource-saving production of high-performance hydrodynamic plain bearings for applications in the wind energy sector. This increases the service life of wind turbine gearboxes and enables the construction of even more powerful wind turbines.
The need for sensors for smart digital solutions is constantly increasing. Fraunhofer ILT is developing methods for the additive integration of sensors into components. This allows for analysis and prediction of failure cases. Printed electronics can be combined with additive manufacturing methods such as Laser Powder Bed Fusion (LPBF). We present a wireless strain gauge (DMS) on a control arm and DMS integrated into a milling head.
Li-ion accumulators with liquid electrolyte are market-leading energy storage systems due to their wide range of applications and high energy densities. In the course of the energy transition, both the demand and the requirements for battery systems are very high.
These range from resource-saving, sustainable production to an increasing demand for higher energy and power densities. By integrating laser-based drying and patterning processes, Fraunhofer ILT offers innovative approaches in the roll-to-roll manufacturing process of lithium-ion batteries to meet the increasing production demands.
By using efficient diode lasers, the water-based electrode layers can be dried in a much more energy- and space-saving way than in complex hot-air oven processes. Furthermore, in the downstream laser structuring process, the power density and service life of the battery cells can be increased using ultra-short pulsed laser radiation. At the same time, industry-relevant process speeds are achieved through the combination with a multi-beam structuring module.
In order to increase efficiency in the production of bipolar plates, forming tools made of high-quality tool steels are replaced by more cost-effective tools made of mild steel and coated with a wear protection layer. The coating is applied using extreme high-speed deposition welding (EHLA). This processing method achieves process speeds of up to 500 metres per minute. The forming tools are finished by laser ablation.
In the course of the energy transition, the demand for technologies such as PEM fuel cells is constantly increasing. The Fraunhofer ILT is developing a laser-based process that enables the production of innovative corrosion protection coatings for bipolar plates (BPP). In this process, a precursor is sprayed onto the BPP and dried. The subsequent functionalization using laser radiation converts this precursor layer into a conductive and corrosion-resistant coating.
The process dispenses with complex and expensive vacuum processes, making it considerably easier to use in a continuous production line. The short interaction time between the laser beam and the workpiece minimises the thermal load on the latter.
In Laser Metal Deposition (LMD), process heat often affects stability and accuracy by creating deviations in layer thickness. To address this, Fraunhofer ILT developed an AI model for dynamic adjustment of laser power during build-up. Trained through image data, the AI model learns correlations between laser power, geometry and other factors in relation to the melt pool area. This enables the prediction of process parameters and reduces the effort involved in process development for AM.
The combination process Simultaneous Machining and Coating (SMaC) developed at the Fraunhofer ILT enables the combination of the EHLA coating process with a subtractive finishing step in parallel with the main production time, thus increasing productivity enormously. In addition to the economic advantages, the SMaC process also offers technological benefits compared to the conventional process chain. The process heat generated in the coating process leads to a softening of the material and thus to easier machining. This makes it possible to produce corrosion and wear protection coatings as well as functional surfaces more quickly and with less wear on the tools. SMaC technology offers considerable advantages, particularly when applying high-strength coating materials that are otherwise difficult to machine.
Besides the requirements for climate protection, the space industry is underlying increasing cost pressure due to international competition. To maintain the European competitiveness, Fraunhofer ILT is part of the ongoing EU project ENLIGHTEN and is developing an additive manufacturing process for rocket nozzles using LMD. The specifications of a rocket nozzle require the productive manufacturing of large components with filigree cooling channels, which is made possible by the LMD technology.
An automated, hybrid process chain for the sustainable repair of metallic components is being developed at Fraunhofer ILT. The focus is on a sequence of subtractive and additive manufacturing processes. First, local material removal takes place in the form of a defined groove geometry at the damaged area. The volume in the pre-machined area is filled additively using EHLA and finally machined to restore the original contour of the component.
Fraunhofer Institute for Laser Technology ILT