This study presents some early results about an innovative approach in laser beam directed energy deposition (DED-LB) technology exploiting a multi wavelength (multiWL) optic head that allows to combine on the same workpiece two laser sources, a blue diode laser beam (450 nm) and an infrared diode laser beam (915 nm), for a more efficient and sustainable DED manufacturing process of a multi material copper-nickel component. The reference scenario was developed using a commercial infrared disk laser and a single beam optic head. The growing complexity of aerospace and aeronautic multi-material products, fueled by the widespread adoption of additive manufacturing calls for solutions to streamline processes, enhance efficiency and cost-effectiveness. In this context, the EU-funded WAVETAILOR project aims to leverage modular laser sources and processing heads to facilitate high-precision manufacturing of complex material structures while minimising environmental footprint and to develop a flexible, energy-efficient photonic setup offering complete adaptability to suit various energy and resource requirements. This research paper illustrates the integration of novel solutions for multiWL DED-LB powder processes in a robotic cell and reports the initial results of multi-material processing with an infrared disk laser source to obtain a functional graded copper-nickel material as a reference scenario for future comparison with the multiWL approach.

Laser shock peening (LSP) uses plasma shock waves to induce compressive residual stress at the surface of a component which has the potential to improve its fatigue properties. For AM parts, the existence of internal defects, surface roughness, and tensile residual stresses leads to noticeably lower fatigue strength compared to materials produced through conventional processes. Furthermore, there is a tendency for greater scatter in the fatigue behavior of these parts when compared to traditionally manufactured components. In this study, the effect of LSP on the roughness and fatigue behavior of Ti-6Al-4V alloy constructed through Laser Powder Bed Fusion (L-PBF) technique was investigated. Two types of samples were designed and tested: as-built surface air foil samples for four-point bending tests and machined surface straight gage samples for uniaxial fatigue testing. Two sets of process parameters, optimized and non-optimized, were also used for the fabrication of each sample type. It was found that LSP had negative effects on the smooth (i.e., machined) surface samples, whereas for as-built surfaces the roughness was enhanced by decreasing the sharpness of the deep valleys and partially remelting the loosely bonded particles on the peaks. It was found that the scatter of the fatigue data decreased for optimized machined samples, while no clear improvement was observed in their lives. However, all non-optimized samples showed improvements in fatigue lives after the LSP process.

With the rapid advancements in Information and Communication Technologies (ICT) and the widespread enthusiasm of both theoreticians and practitioners, the broader transition to Industry 4.0 (I4.0) in major industries appears imminent. This empirical study analyzes business data from 1140 automotive companies operating in Europe, utilizing various business intelligence platforms and employing decision tree analytics to establish connections between enablers, drivers, company size, and financial resources. The goal is to identify persistent barriers hindering the rational transition to Industry 4.0. The findings reveal an uneven transformation within the industry nexus. While larger companies possess the financial means to allocate collective intelligence, technical resources, and drive necessary for fulfilling I4.0 requirements, smaller members of the nexus lag behind despite their enthusiasm and intent. This imbalanced evolution poses a threat to the comprehensive transformation required for realizing all the benefits of Industry 4.0 within the sector. The primary discovery indicates that small to medium-sized enterprises do not exhibit the same rates of Industry 4.0 adoption, a lag highly correlated with their available financial and human resources for digital transition. The decision tree proposed in this study offers guidelines for achieving an Industry 4.0-compliant nexus. Given its diversity and substantial global impact, the case study from the automotive industry proves intriguing and may later be generalized to other sectors. The study’s outcome could empower engineering managers and researchers to implement, execute, and assess the impact of digital strategies based on the financial capabilities of industrial institutions.

The present work aimed to improve the surface integrity of the selective laser melting manufacturing (SLM) manufactured 10 mm sized meso gears using the unconventional Laser Peening without Coating (LPwC) tech-nique. To accomplish LPwC on meso gears low energy in the range of 200 mJ to 1000 mJ at 10 Hz were applied underwater in the gear root and fillet gap generating significant surface compressive residual stresses (from +73 MPa to-298 MPa). Besides the surface, residual stresses, average surface roughness (Ra), arithmetical mean height (Sa) and parameters of the material ratio curve were also considered as a part of the study. Notable improvement was achieved in Sa, as it improved over 50 % while considerable improvement in Ra and the material ratio curve parameters has also been observed. Scanning electron microscopy confirmed that the void and porosity seen in the unpeened gears were filled. The electron backscatter diffraction analysis confirms the grain refinement in LPwC region up to 100 mu m depth. It was observed that multifold dislocation occurs within the grain, and dislocation generates sub-grain. The sub-grain formation substantially inhibits further nucleation and crack propagation owing to an increase in grain boundary density. Such improvement justifies the set objectives, and the outcome of this research will pave a foundation to improve the overall performance of the micro/meso parts using the LPwC process.

Present work aims to study the fatigue life behaviour of additively manufactured (AM) stainless steel 316L in a laser shock peening (LSP) process. The fatigue behaviour of as-built samples and LSPeened sample were studied on the AM samples. A new diode-pumped laser system was utilized as an instrument to perform LSP operations. LSP operation was performed under two different sacrificial layers of different materials i.e. vinyl tape and aluminium tape. The other essential LSP parameters, namely energy, pulse width, spot size, overlap, and number of layers were kept constant based on the previous experimental findings. The characterization was done for analyzing the residual stresses using a hole drilling process, and a 4-point bending machine. A considerable improvement in compressive residual stress and fatigue life was observed in the LSPeened samples. Such improvements in residual stresses and fatigue life may pave a road to establishing diode-pumped lasers for LSP applications.

Metal Additive Manufacturing has been recognized as a technology of the future providing numerous benefits such as the production of complex shape and lightweight parts, easy customization, design freedom, etc. However, there are many areas where metal additive manufacturing cannot be applied since the quality of produced parts still does not satisfy the requirements of high-demanding industries for the production of their critical parts. Recently, Laser Shock Peening (LSP) has been investigated as a post-processing technique in metal additive manufacturing, primarily for the improvement of fatigue behavior. Here we will present improvements in fatigue life, the analysis of microstructure, and all the benefits LSP can bring to Metal Additive Manufacturing, for two types of material; stainless steel AISI 304L and titanium alloy Ti6Al4V.

Superhydrophobic surfaces attract a lot of attention due to many potential applications including anti-icing, anti-corrosion, self-cleaning or drag-reduction surfaces. Despite a list of attractive applications of superhydrophobic surfaces and demonstrated capability of lasers to produce them, the speed of laser micro and nanostructuring is still low with respect to many industry standards. Up-to-now, most promising multi-beam solutions can improve processing speed a hundred to a thousand times. However, productive and efficient utilization of a new generation of kW-class ultrashort pulsed lasers for precise nanostructuring requires a much higher number of beams. In this work, we introduce a unique combination of high-energy pulsed ultrashort laser system delivering up to 20 mJ at 1030 nm in 1.7 ps and novel Diffractive Laser-Induced Texturing element (DLITe) capable of producing 201 × 201 sub-beams of 5 µm in diameter on a square area of 1 mm2. Simultaneous nanostructuring with 40,401 sub-beams resulted in a matrix of microcraters covered by nanogratings and ripples with periodicity below 470 nm and 720 nm, respectively. The processed area demonstrated hydrophobic to superhydrophobic properties with a maximum contact angle of 153°.

Reflectivity and surface topography of tempered glass were modified without any thermal damage to the surroundings by utilizing 1.7 ps ultrashort pulsed laser on its fundamental wavelength of 1030 nm. To speed up the fabrication, a dynamic beam shaping unit combined with a galvanometer scanning head was applied to divide the initial laser beam into a matrix of beamlets with adjustable beamlets number and separation distance. By tuning the laser and processing parameters, reflected intensity can be reduced up to 75% while maintaining 90% of transparency thus showing great potential for display functionalization of mobile phones or laptops.

We present the setup of a compact, q-switched, cryogenically cooled Yb:YAG laser, which is capable of producing over 1 J output energy in a 10 ns pulse at 10 Hz. The system’s design is based on the recently published unstable cavity layout with gain shaping of the spatial intra-cavity intensity distribution. Using a hexagonal homogenized pump beam, the laser generated an according hexagonal output beam profile. The suitability of such laser properties for the intended use in a laser shock peening process is demonstrated. In the experiment an aluminum plate was treated and the generated residual stresses in the sample subsequently measured. Other applications of this laser system like laser pumping or surface cleaning are conceivable.

A unique combination of the ultrashort high-energy pulsed laser system with exceptional beam quality and a novel Diffractive Optical Element (DOE) enables simultaneous production of 2601 spots organized in the square-shaped 1 × 1 mm matrix in less than 0.01 ms. By adjusting the laser and processing parameters each spot can contain Laser Induced Periodic Surface Structures (LIPSS, ripples), including high-spatial frequency LIPSS (HFSL) and low-spatial frequency LIPSS (LSFL). DOE placed before galvanometric scanner allows easy integration and stitching of the pattern over larger areas. In addition, the LIPSS formation was monitored for the first time using fast infrared radiometry for verification of real-time quality control possibilities. During the LIPSS fabrication, solidification plateaus were observed after each laser pulse, which enables process control by monitoring heat accumulation or plateau length using a new signal derivation approach. Analysis of solidification plateaus after each laser pulse enabled dynamic calibration of the measurement. Heat accumulation temperatures from 200 to 1000 °C were observed from measurement and compared to the theoretical model. The temperature measurements revealed interesting changes in the physics of the laser ablation process. Moreover, the highest throughput on the area of 40 × 40 mm reached 1910 cm2/min, which is the highest demonstrated throughput of LIPSS nanostructuring, to the best of our knowledge. Thus, showing great potential for the efficient production of LIPSS-based functional surfaces which can be used to improve surface mechanical, biological or optical properties.

When applying picosecond laser pulses of the order of several mJ pulse energy, the goal is to deliver the pulses effectively to the surface. HiLASE have development novel diode pumped thin-disk laser systems which are used for high speed drilling (700 holes simultaneously) and high speed surface structuring (several cm2 per second). Different methods of multi-beam processing will be presented.

Optimization of the laser shock peening (LSP) and LASer Adhesion Test (LASAT) processes requires control of the laser-induced target's loading. Improvements to optical and laser technologies allow plasma characterization to be performed with greater precision than 20 years ago. Consequently, the processes involved during laser–matter interactions can be better understood. For the purposes of this paper, a self-consistent model of plasma pressure versus time is required. The current approach is called the inverse method, since it is adjusted until the simulated free surface velocity (FSV) corresponds to the experimental velocity. Thus, it is not possible to predict the behavior of the target under shock without having done the experiments. For the first time, experimental data collected in different labs with the most up-to-date laser parameters are used to validate a self-consistent model for temporal pressure-profile calculation. In addition, the parameters characterizing the plasma (temperature, thickness and duration) are obtained from the ESTHER numerical code, together with the amount of ablated matter. Finally, analytic fits are presented that can reproduce any pressure–temporal profiles in the following domains of validity: intensities, I, ranging from 10 to 500 GW cm−2 and pulse durations, Tpul, between 5 and 40 ns for the direct-illumination regime at 1053 nm, I ranging from 1 to 6 GW cm−2 and Tpul between 10 to 40 ns in the water-confined regime at 1053 nm, and I from 1 to 10 GW cm−2 and Tpul between 7 and 20 ns in the water-confined regime at 532 nm. These temporal pressure profiles can then be used to predict the aluminum target's behavior under laser shock using mechanical simulation software.

Using four beam direct laser interference patterning (DLIP) Laser Induced Periodic Surface Structures (LIPSS, ripples) are simultaneously generated on surface of AISI 316L steel in more than thousands of spots at once. Both low-spatial frequency LIPSS (LSFL) and high-spatial frequency LIPSS (HFSL) are possible to fabricate with optimized parameters of 1030 nm, 1.7 ps PERLA laser system, developed and operated at HiLASE center. A novel large-beam DLIP technique applied for the redistribution of initial laser energy per pulse results in fabrication of similar to 1520 spots with LSFL in 50 ms and similar to 1016 spots with HSFL in 5 ms, thus significantly improving the productivity in comparison with the single beam approach. Efficient production of LIPSS structures over large area, required for applications such as a production of security diffractive elements and surfaces with super-hydrophobic properties is also demonstrated. Possible steps for further increase of processing speed are discussed.

A series of tacrine - benzothiazole hybrids incorporate inhibitors of acetylcholinesterase (AChE), amyloid beta (A beta) aggregation and mitochondrial enzyme ABAD, whose interaction with AO leads to mitochondrial dysfunction, into a single molecule. In vitro, several of 25 final compounds exerted excellent anti-AChE properties and interesting capabilities to block A beta aggregation. The best derivative of the series could be considered 10w that was found to be highly potent and selective towards AChE with the IC50 value in nanomolar range. Moreover, the same drug candidate exerted absolutely the best results of the series against ABAD, decreasing its activity by 23% at 100 mu M concentration. Regarding the cytotoxicity profile of highlighted compound, it roughly matched that of its parent compound - 6-chlorotacrine. Finally, 10w was forwarded for in vivo scopolamine-induced amnesia experiment consisting of Morris Water Maze test, where it demonstrated mild procognitive effect. Taking into account all in vitro and in vivo data, highlighted derivative 10w could be considered as the lead structure worthy of further investigation.

Recently, we published a novel design approach for unstable laser cavities that overcomes the limitation of such a design to high gain media and presented first results of a laboratory prototype [1]. Based on this, we developed a larger prototype system suitable for applications in laser shock peening featuring a relatively simple layout and a compact footprint of about 0.8x0.6m². The presented laser is based on cryogenically cooled Yb:YAG ceramic equipped with a Cr:YAG absorber cladding to suppress amplified spontaneous emission. As the pump source we utilize a 7kW peak power laser diode module generating a high quality tophat beam with hexagonal lateral profile. With this the system achieves an output energy in excess of 1J in a 10ns to 20ns pulse in q-switch operation mode. The output beam profile adapts well to the hexagonal shape of the pump beam. The laser can be operated with up to 20Hz repetition rate limited only by the cooling capacity of the used cryostat. The application of the system in laser shock peening (LSP) was tested by treating aluminum plates within a test setup. The treated area was then examined regarding residual stress to verify the success of the LSP process. It was found that significant residual stress was generated with a penetration depth of up to 0.6mm and a pressure of 200MPa at the surface. [1] J. Körner, S. Zulić, D. Rostohar, A. Lucianetti, T. Mocek, “Novel unstable resonator configuration for highly efficient cryogenically cooled Yb: YAG Q-switched laser”, Optics Express, 27(15): 21622-21634, 2019

The fabrication of functional microstructures on surfaces by laser enables unique material properties and is presently a leading research topic. This work addresses the production of functional hierarchical microstructures on carbon fibre reinforced polymer composites in order to control the wettability properties of the material. Two-beam Direct Laser Interference Patterning using either ultraviolet (263 nm) or infrared (1053 nm) nanosecond laser source is employed to produce melt-free and well-defined hierarchical microstructures on carbon fibre reinforced plastics. The resulting water contact angles after thin film deposition of 1H,1H,2H,2H-Perflorodecyl-triethoxysilane were analysed with respect to structure depth and quality. The maximum static contact angle of 171 degrees is demonstrated for dual hierarchical microstructures composed of 11 mu m deep large-scale pillars, covered by 1.7 mu m pillars, both fabricated in a single step.

To fulfil the requirements for high-resolution organic light-emitting diode (OLED) displays, precise and high-quality micrometer-scale patterns have to be fabricated inside metal shadow masks. Invar has been selected for this application due to its unique properties, especially a low coefficient of thermal expansion. In this study, a novel cost-efficient method of multi-beam micromachining of invar will be introduced. The combination of a Meopta beam splitting, focusing and monitoring module with a galvanometer scanner and HiLASE high-energy pulse laser system emitting ultrashort pulses at 515 nm allows drilling and cutting of invar foil with 784 beams at once with high precision and almost no thermal effects and heat-affected zone, thus significantly improving the throughput and efficiency.

In this paper, we introduce a method to efficiently use a high-energy pulsed 1.7 ps HiLASE Perla laser system for two beam interference patterning. The newly developed method of large-beam interference patterning permits the production of micro and sub-micron sized features on a treated surface with increased processing throughputs by enlarging the interference area. The limits for beam enlarging are explained and calculated for the used laser source. The formation of a variety of surface micro and nanostructures and their combinations are reported on stainless steel, invar, and tungsten with the maximum fabrication speed of 206 cm2/min. The wettability of selected hierarchical structures combining interference patterns with 2.6 µm periodicity and the nanoscale surface structures on top were analyzed showing superhydrophobic behavior with contact angles of 164°, 156°, and 150° in the case of stainless steel, invar, and tungsten, respectively.

A lot of research efforts have been invested in the fabrication of superhydrophobic surfaces in recent years due to many protentional applications in science and industry including anti-icing, self-cleaning and anti-corrosive surfaces. Laser as a non-polluting, precise and flexible tool can be applied to replicate surface microstructures of extremely water repellent lotus leave surface. In this study, a common nanosecond laser source is used to fabricate a super/ultrahydrophobic surfaces with different microstructure designs, contact angles above 170 degrees and sliding angles below 5 degrees. The freshly processed surface is hydrophilic and becomes hydrophobic and superhydrophobic in a certain time period, which could be dramatically reduced by storing samples in high vacuum. The transformation in wetting properties are analysed with respect to surface geometry and surface chemistry.

Growing demand for superhydrophobic surfaces in recent years is associated to many attractive science and engineering applications including self-cleaning, anti-icing and anti-corrosive behaviours. Stainless steel type AISI 316L is one of the most versatile and widely used engineering material in industries. Inspired by the "lotus effect" nano/microstructures has been fabricated by direct laser writing method with nanosecond laser source using two ablation regimes. Primarily, microstructures were fabricated with a tightly focused beam and covered by nano-scale structures by defocused laser beam in the second fabrication step. However, freshly prepared laser patterned metal surface shows hydrophilic behaviour. The hydrophilic to superhydrophobic transformation takes several days or weeks by aging technique in atmospheric condition. In this study, the transition time has been drastically reduced by high vacuum processing technique. Wetting properties with respect to laser processing parameters and surface morphology were examined and found to be consistent for large droplet volumes.