LaserApplicationCenter (LAZ)

In additive manufacturing, the component is built up layer by layer in several steps. With the TruPrint 1000, we produce the components layer by layer from metal powder using the 3D printing process. To do this, we completely fuse the powder grains with the laser and can, for example, build parts from two different materials such as hard metals, magnetic or highly reactive materials. This is important for materials research or the development of new materials for e-mobility, for example.

Cutting with the laser beam enables us to process almost all material groups without contact. Cutting tasks can be carried out with micrometre precision and the highest quality. The development of innovative lasers has made them an indispensable cutting process, especially in metalworking. Both plate-shaped materials and 3D bodies can be cut without burrs.

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Joining techniques include laser beam welding and laser beam soldering: laser welding creates material-locking, metallic Fraternities and sororities/clubs in numerous seam and joint configurations. The outstanding feature of laser soldering is the non-contact melting of the solder with exact distribution of the energy supply to the solder and joining partner. We also have various attachments available for this, such as the TLC 1005, which consists of; have five axes and an additional rotary axis for 3D processing. It can be used for welding and high-temperature soldering. Thanks to various laser sources, our 6-axis robot not only enables 3D material processing in the robot cell, but also robot-assisted adhesive joining.

© Aalen University of Applied Sciences | Markus Hofele, doctoral candidate, doctoral student at the LaserApplicationCenter, aligns the 3D scanner in the new robot cell. The processing head guides the laser beam over the workpiece using movable mirrors.

Laser beam welding

In this joining process, an inseparable joint is created between two workpieces or components with targeted heat input. As a rule, none of the filler material is used. For welding, a laser beam is pooled by focusing optics and directed at the workpiece. The joint is then heated to welding temperature. A gas protects the weld seam to prevent oxidation. As the heat input remains low due to the strong bundling of the laser beam, the components exhibit little distortion. The weld seams are usually very narrow. Areas of application include sheet metal processing and Tool making & forming.

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Laser beam soldering

The laser is ideal for the three soldering processes - soft soldering, hard soldering and high-temperature soldering. It works without contact and the parameters are easy to control, making laser beam soldering a good alternative to welding for Fraternities and sororities/clubs with high demands on temperature resistance and mechanical strength. Laser soldering is usually realized using a soldering optic that is integrated into a robot. The laser beam is guided along the joint where it melts the brazing alloy - such as a copper-silicon wire - and thus joins the components. The success of the laser soldering process is based on the weld-like strength and the high aesthetic quality of the joints: Laser soldered seams are known for their dense, smooth and clean structures. This is visually attractive and reduces reworking to a minimum.

© Aalen University of Applied Sciences | Temperature-controlled high-temperature capillary gap brazing produces extremely strong joints on stainless steels.

© Aalen University of Applied Sciences | Laser beam soldering of a fillet weld joint with copper as solder

Laser polishing is a surface finishing process for metallic workpieces, thermoplastics and glass. The material begins to flow as it is heated. The surface roughness is smoothed due to the surface tension, roughness peaks are removed and profile depths are filled. The laser beam can be used to polish complex geometries that cannot be processed using mechanical polishing. Thanks to the "remelting" principle, none of the material is removed during laser polishing - unlike conventional machining processes, such as grinding and polishing. The surface solidifies from the melt without cracks or pores, smoothing out any sharp-edged structures on the surface.

© Aalen University of Applied Sciences | Laser polishing enables highly efficient surface smoothing of additively manufactured 3D components.

Laser-based heat treatment can be used to temper surfaces locally and selectively. For this purpose, the laser beam is guided over the surface using highly dynamic scanner optics. The temperature in the laser beam is measured using an inline pyrometer and controlled highly dynamically. Depending on the elected exposure times and process temperatures, different heat treatment processes such as stress relief annealing to reduce residual stresses, local softening of forming zones or high-strength crash structures, microstructural transformation to adapt the mechanical properties or surface hardening for wear surfaces can be realized.

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Our ultrashort pulse laser has pulse durations in the nanosecond to femtosecond range with extremely high pulse peaks. This has enormous advantages for material processing. The intense light input vaporizes the material hit at specific points, resulting in high-precision structures, cut edges and drill holes. Due to the extremely short interaction time, cold and burr-free processing is possible, which means that heat-sensitive surfaces can also be processed. Surface structuring with USP lasers can also replace coatings and be used specifically for functionalization.

© Aalen University of Applied Sciences | Short, high-energy laser pulses can ablate the finest layers or functionalize surfaces, for example in battery production or glass.

A clean surface is the prerequisite(s) for durable welded and bonded joints. Components are often contaminated, oxidized or coated with protective layers before joining. This is where the laser can help: the TruMark 5020 removes dirt, oxidation and functional layers from components in a matter of seconds. And only where joining is required, for example. This is how it works: pulses with high peak pulse powers vaporize the wafer-thin layers without affecting the component. Thanks to the 2D scanner, which is guided by a 3-axis system, our short-pulse laser can also functionalize or mark the surfaces at the desired points.

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During laser ablation, the finest layers of the surface are removed from a workpiece in individual, thin layers. The basis of this ablation process is material ablation triggered by short, high-energy laser pulses. Laser ablation can be performed in points, areas or strips. Ablation is mostly used in Tool making & forming as well as in Electronics and semiconductor technology. For example, the laser creates three-dimensional, detailed advanced courses / specialties in injection moulding tools, the shapes of which are later reproduced in the plastic part during injection molding. The laser can also selectively ablate thin layers, for example to trim resistors or for labeling.

© Aalen University of Applied Sciences | This is what a scanning electron microscope image of a laser-structured stamp for micro-embossing electrodes looks like.