In this work, we introduce a simple and universal optical setup design for laser surface texturing (LST) that provides functionality superior than direct laser interference patterning (DLIP). The method requires only a single periodic diffractive optical element and a focusing lens while enabling unlimited freedom for spatial shaping and amplitude variations. The concept is based on the special behavior

This study focused on the potential of topology optimization (TO) for metallic tertiary structures of spacecrafts produced by the additive manufacturing (AM) technique laser powder bed fusion. First, a screening of existing conventionally manufactured products was carried out to evaluate the benefits of a redesign concerning product performance and the associated economic impact. As a result of the

A routine for color marking using oxide layers and laser-induced periodic surface structures is presented. Titanium and alloys thereof are marked with pixelated graphics at a high resolution with tempering colors. A computational approach for the laser path calculation enables a fast-forward marking of complex designs. The color map attained from a laser parameter studies enables vivid coloration.

Solid-solution and carbide-strengthened superalloys such as Haynes 230 are the materials of choice for the hot-section components of gas turbines, e.g., combustion cans and transition ducts. Under severe thermal conditions, to which those parts are exposed, creep strength is a crucial property of the related materials during their lifetime. Recently, the introduction of serrated grain boundaries in

The geometry of the cutting front and the cutting kerf was measured with an online high-speed x-ray diagnostic system. X-ray videos from fusion cutting of 10 mm thick stainless steel samples were recorded with a frame rate of 1000 Hz. A three-dimensional reconstruction of the time-averaged geometry of the cutting front and cutting kerf out of these images made it possible to apply ray-tracing for calculating

Additive manufacturing processes have the potential to produce near-net shaped complex final parts in various industries such as aerospace, medicine, or automotive. Powder bed based and nozzle based processes like laser metal deposition (LMD), laser powder bed fusion (LPBF), and electron beam melting (EBM) are commercially available, but selecting the most suitable process for a specific application

The authors report on surface modification by laser-induced periodic surface structures of different periodicities and modulation depths to modify dry and lubricated tribological properties. Using 220 fs laser pulses in the infrared ( λ 1 = 1030 nm), visible ( λ 2 = 515 nm), and ultraviolet ( λ 3 = 343 nm) spectral regions, the authors periodically structure two-dimensional areas with periodicities

The present study explores an experimental investigation of dissimilar welding of austenitic stainless steel (AISI 316) with nitinol (NiTi) plates by inserting copper (Cu) as an interlayer using a fiber laser system. The presence of copper influences controlling the formation of brittle intermetallic compounds forming compounds of copper with iron, titanium, and nickel. The weldments are examined to

The original morphology of the oxide layer and the surface of the titanium alloy has a significant impact on manufacturing and processing. The laser cleaning pulse frequency amplitude affects the single pulse energy. It will affect the original morphology of the surface and the compositional changes of the laser-generated oxide layer. This work aims to study the effect of pulse frequency on the surface

Laser-induced breakdown spectroscopy (LIBS) is a sensitive optical technique capable of rapid multielemental analysis. The development of this technique for elemental analysis in traditional Chinese medicine can eventually revolutionize the pharmaceutical industry. The detection and identification of real and fake elements in traditional Chinese medicine is very important, and saffron is a typical

The authors characterize femtosecond laser single-pulse machining of deep, micrometer-diameter holes and long, micrometer-width channels in fused silica by the use of spherical, cylindrical, and aspheric singlet lenses. Repositionable spherical lenses form an adjustable beam expander that also provides a means of minimizing—or deliberately introducing—spherical aberration (SA) in the focal region by

In this paper, fiber laser-arc hybrid welding plasma was studied by using the multiple-imaging method. Four images of plasma with different light intensity areas can be simultaneously observed in a picture. The arc plasma and metal plasma can be distinguished in the high light intensity area, and the arc plasma has an approximate average light intensity distribution. The metal plasma is mainly concentrated

Laser cleaning of rusted surfaces has broad applications in marine ship industrial manufacturing. An ultraviolet nanosecond laser cleaning method was proposed to strip the rust layer from the surface of the AH36 steel to reduce surface roughness and increase corrosion resistance. Multi-pulse laser ablation was established to determine the single-pulse threshold fluence and pulse incubation coefficient

Preservation of cultural legacy is essential for ensuring its availability for future generations. Long-term indoor storage can sometimes cause the papers to adhere, which can result in the transfer of ink stamps or prints from paper to paper, and subsequently, there emerges the need to remove these types of stains. Laser cleaning emerged as a promising technique for paper surface cleaning. This work

Several experiments are performed to explore the possible benefits of using bamboo charcoal as a sample holder for rapid powder analysis using laser-induced breakdown spectroscopy at low-pressure helium ambient gas. Standard powdered samples such as ZnS and CuSO4 are used to demonstrate the feasibility of using cheap and widely available bamboo charcoal as a sample holder. A commercial baby milk powder

In order to investigate the overlap rate of an ablated spot on monocrystalline silicon by a femtosecond laser, a skewness spot derived from plasma is analyzed. First, the serial spot image is collected, and the ablated core area of the spot is extracted by the way of bit image layering so that the peripheral halo can be eliminated effectively. The image of the spot is enhanced by Gaussian-guided filtering

The current laser safety standards do not address specifically how to account for repetitively pulsed lasers with irregular pulse trains. Variations in peak power, pulse duration, and duty cycle within a pulse train pose a number of problems when it comes to product classification or to assess the hazard of a given exposure. This study proposes to analyze irregular pulse trains by generalizing the

An electro-optic Q-switched multiwavelength laser diode array end-pumped Nd:YAG laser without temperature control is proposed and demonstrated in this paper. Using a 3.2 kW multiwavelength laser diode array as the pump source, a lens duct as the coupling system, RTP crystals as the Q-switch, and an end-pumped Nd:YAG crystal rod (Ø 6 × 60 mm2) as the gain medium, the laser system obtained a maximum

Developing laser welding (LW) technology in a hyperbaric environment is significant for manufacturing and maintaining nuclear power facilities, offshore engineering structures, etc. However, the penetration is significantly reduced during LW in a hyperbaric environment, which has not been solved yet. Previous research has shown that compared with the penetration of LW in a hyperbaric argon (Ar) environment

Ti6Al4V alloy exhibits good biocompatibility and has a wide range of applications in the medical fields. Additive manufacturing, especially selective laser melting (SLM), provides a new and effective way for the fabrication of Ti6Al4V alloy biological components. The corrosion resistance of SLM processed Ti6Al4V alloy needs further investigation, which is important for the application of biological

Fe-Cr-C near-eutectic alloys are commonly used in wear resistant parts in mining applications, due to their excellent erosion and abrasion wear resistance. Laser metal deposition is an additive technology that presents opportunities for manufacturing mining components, as well as repairing worn areas of wear resistant parts. However, Fe-Cr-C hypoeutectic alloys are very hard and brittle and are often

The study aims to understand the carbonization mechanism when an ns NIR transparent fiber laser beam irradiation of polycarbonate (PC) instead of irradiation using a UV laser beam or ultrashort pulsed laser beam. It reveals that PC can be decomposed with an ns transparent 1064 nm laser beam. The laser fluence threshold under which to cause ablation in PC was not a constant value. The threshold decreased

The influence of wire feeding speed during laser welding with a filling wire was investigated by high-speed imaging and mechanical analysis of the droplet. A force relationship was found to analyze the droplet transition behavior at the end of the welding wire in the narrow-gap groove. Welding defects, mainly including nonfusion and porosity, were studied to reveal the formation mechanism and propose

In the additive manufacturing (AM) process, metal powder can be directly used to produce metal components. Unfortunately, a large thermal gradient is developed during the AM process, which leads to the generation of residual stress and complex shape-distortions. In this study, the influence of the geometrical size and structural features of a hollow Ti-alloy blade prepared by the AM process on the

Phase change heat transfer allows high heat transfer rates associated with small temperature variations. Given that this technique is employed in several energy and industry applications, such as automotive air-conditioning evaporators, pulsating heat pipes are used for aerospace thermal management and in semiconductor-manufacturing heat exchangers. Although phase change heat transfer has served mankind

Remote laser welding (RLW) combines the positive features of tactile laser welding with additional benefits such as increased processing speed, reduced operational cost and service, and higher process flexibility. A leading challenge preventing the full uptake of RLW technology in industry is the lack of efficient closed loop in-process (CLIP) monitoring and weld quality control solutions. This underpins

Additive manufacturing of metal matrix composite (MMC) is a challenging field to explore. Besides components’ geometric constitution, requirements related to final microstructures must be met. Depending on the application, such as tribology, machining, or magnetism related, there is a need to preserve a specific phase, which is generally responsible for the engineering function of the fabricated component

Direct joining of metals and polymers is a promising approach for today’s challenges in joining technology due to fast cycling time, its robustness, and the absence of duroplastic adhesives. Laser pretreatment of the metallic surface has been proven to enhance joint strength and has become a popular method for joining hybrid components. However, the versatility of the laser process allows the generation

Powder based laser material deposition (LMD) is a suitable additive manufacturing technology for repair and overhaul of metal parts as well as for the build-up of new parts. This technology is used in industrial applications as automotive, turbomachinery, aviation, or tool making [T. Jambor, “Funktionalisierung von Bauteiloberflächen durch Mikro-Laserauftrag-schweißen,” Ph.D. thesis, RWTH Aachen University

Laser beam welding significantly outperforms conventional joining techniques in terms of flexibility and productivity. The process benefits, in particular, from the highly focused energy and thus from a well-defined heat input. The high intensities of brilliant laser radiation, however, induce very dynamic effects and complex processes within the interaction zone. The high process dynamics require

Superhydrophobic surfaces have been attracting considerable attention due to potential applications in self-cleaning, anti-icing, water/oil separation, drag reduction, water collection, etc. However, to date, except for a few textile surfaces and coating products, only a limited number of superhydrophobic applications have been commercialized. The main reasons for the limited number of applications

In this work, laser cladding of a Ni-based superalloy powder (Inconel 718) on a Fe-based superalloy (A-286) substrate was performed. The microstructural evolution was studied by optical and electron microscopy techniques, aided by energy dispersive spectroscopy. Additionally, the microhardness along the as-deposited parts was analyzed and correlated with the observed microstructure. It was found that

The formation of self-assembled laser induced periodic surface structures (LIPSSs) after ultrashort pulsed laser ablation is still a matter of controversy in the literature. There is agreement that at least two different physical driving forces lead to ripples with distinguishable spatial periodicity. High spatial frequency LIPSSs with periodicity well below the incident wavelength are discriminated

A novel approach for the reconstruction of an equivalent volumetric heat source from a known weld pool shape is proposed. It is based on previously obtained weld pool geometries from a steady-state thermo-fluid dynamics simulation. Hereby, the weld pool dimensions are obtained under consideration of the most crucial physical phenomena, such as phase transformations, thermo-capillary convection, natural

In this study, using ultrafast lasers of 10 ps pulse duration as a precise and efficient method for cutting edge preparation is researched. Cutting edge preparation is an important step within cutting tool manufacturing, while unprepared sharp cutting edges show low stability, which leads to tool failure by high mechanical and thermal loads during the turning processes [C. F. Wyen, W. Knapp, and K

Material processing by ultrafast lasers is an attractive technology for high-precision fabrication, such as cutting, drilling, and surface modification, of a wide range of material, including dielectrics, semiconductor, metals, and polymer composites. However, it is still challenging to apply ultrafast laser processing in many applications because some key processes, such as absorption and heat accumulation

Problems related to component wear are one of the biggest challenges faced by industrial sectors such as agriculture, mining, and oil and gas. Coating application has been a good alternative to mitigate these problems. Ni-Cr-B-Si alloys are recognized for their abrasion and adhesion resistance properties. In this context, a comparison between the mechanical wear of Ni-Cr-B-Si 1545-00 deposited via

With the rapid development of high-power lasers, efficiency of laser cutting and thickness of cutting material have been greatly increased. In this study, a 10 kW fiber laser was used to cut 18 mm thick 316L stainless steel sheets. The surfaces and cross sections of samples were observed by an optical microscope and a scanning electron microscope. It was found that the quality of laser cutting was

Although different forms of renewable energy sources are in expansion, the oil and natural gas industry remains essential, maintaining its demand for more efficient methods for product transportation. The most productive and safe way is the flow through pipelines. However, pipeline usage directly involves several wear mechanisms, which contribute to pipeline degradation and, consequently, the need

Hybrid laser-arc welding (HLAW) is regarded as a promising joining process, since it can compensate disadvantages from laser autogenous welding and arc welding by uniting both techniques into a single melt pool. Such a process can achieve relative high quality metallurgical bonding, high speed, and low deformation. However, the process is considered complex and of difficult parametrization, as the

The aluminum alloy AA6082 is often used in high-voltage storage systems due to its favorable electrical and mechanical properties. Laser beam welding is a flexible process for producing the required welds. To protect the sensitive components of the battery cells, the required weld depth must be maintained in order to avoid destruction of the components and to reduce the number of defective parts. Optical

In the field of automotive manufacturing, it is pivotal to obtain a moderate penetration status when joining automotive parts by laser keyhole welding. As a typical characteristic of laser keyhole welding, keyhole behavior can directly reflect the penetration status of the weld bead. In this paper, a coaxial vision monitoring system with a laser auxiliary illuminant is established to collect the keyhole

Welding copper to itself and other metals is challenging using conventional welding techniques. The process window for welding copper with an infrared (IR) laser, resistance welder, or an ultrasonic welder is very narrow. In the case of the infrared laser, the high reflectivity at these wavelengths makes it difficult to couple the power into the material and control the temperature of the weld puddle

International thermonuclear experimental reactor correction coil cases are made of heavy, thick, high strength, and high toughness austenitic stainless steel 316LN. The BTCC (bottom and top correction coils) case has the dimension of 2.5 × 7 m2 and cross section of 239.8 × 146.7 mm2, side correction coil case has the dimension of 7.2 × 7.6 m2 and cross section of 147.8 × 168 mm2, and they will be closure

At Fraunhofer IWS Dresden, different, partially prototypic high-power continuous wave (cw) beam sources for the remote laser processing of nonmetals with galvanometric-driven scanner systems are available. The emitted wavelengths of the lasers cover the range from visible light to mid-infrared. A spectroscopic analysis was performed to gain insight into the processability of typical nonmetal materials

The authors report on the theoretical and experimental studies of laser-induced optical breakdown on the surface of fused silica to elucidate the influence of time delay and spatial separation between two ultrashort pulses on the position and size of the modification. Carriers involved in the damage formation including free electrons in the conduction band and self-trapped excitons (STEs) are investigated

The additional element from the filler wire in the laser beam welding is usually distributed inhomogeneously in the final weld due to the high solidification rate of weld pool. It has been found that the electromagnetic stirring produced by an external oscillating magnetic field can enhance the material mixing in the weld pool to achieve a more uniform element distribution. However, the magnetic field

Refined grain size structure is one of the most sought-after features during parameterization of welding processing. Refined grains in the region of the molten zone provide high tenacity in addition to high hardness, due to the dislocation blocking by grain boundaries. However, obtaining refined grain structure is not trivial, since a molten pool is formed during bonding of materials via welding, which

The control of friction and wear is a major concern in many industrial applications. A promising method for tailored surface modification is the so-called laser implantation technique. This method combines surface texturing and material optimization in one processing step by a localized dispersing of hard ceramic particles using pulsed laser radiation. Wear resistant, protruding micrometric features

Additive manufacturing technologies are characterized by complex process interrelations. Consequently, specifically adapted alloys are required to enable a robust building process. In particular, laser beam melting (LBM) is increasingly used for the fabrication of sophisticated functional parts for various applications in numerous industrial sectors, such as automotive and aerospace. However, process

Convoluted rough surfaces involving overhanging features can be a natural consequence of laser additive manufacturing and other spray techniques or can be generated deliberately by laser surface texturing, e.g., to aid osseointegration. Overhanging features add an extra level of complexity to the topography of a rough surface and can have a substantial effect on wettability, etc. However, features

Laser beam welding of aluminum die casting is challenging. A large quantity of gases (in particular, hydrogen) is absorbed by aluminum during the die-cast manufacturing process and is contained in the base material in solved or bound form. After remelting by the laser, the gases are released and are present in the melt as pores. Many of these metallurgic pores remain in the weld seam as a result of

To develop highly efficient and low-cost electrocatalysts based on earth-abundant elements for oxygen evolution reaction (OER) is a great challenge for electrocatalytic water splitting. Herein, a unique type of NiFe-based oxide catalyst with abundant defects is successfully synthesized via pulsed laser ablation in a specific atmosphere containing reductive NH3. The catalyst is self-supported and assembled

Due to increased absorptivity of laser light at 515 nm wavelength in copper materials, welds with low formation of spatters and homogeneous weld depths can be performed.1 However, depending on the used process parameters, a process regime with strong formation of pores is observed. These pores are not resulting from instabilities of the capillary (process pores), but they are observed to result from

The rapidly growing technological innovation of directed energy deposition leads to an increase in part complexity as well as quality and mechanical properties of manufacturable components. However, the variety of process parameters and influencing factors still requires skilled operators, who observe the machine tools. For an unobserved use of deposition welding machines, well parametrized and validated

The phenomenon of thermal focus shift in optical systems, mainly caused by thermal lensing, is well known. There are numerous publications dealing with this effect, but they do not answer the question of how relevant this problem is to the practical application of lasers in laser cutting machines. In this paper, we examine the effect of the thermally induced change of the focus position on the quality

Additive manufacturing using preplaced powder became a widely used processing method during the last few years to build complex and precise structures. The laser beam is often used as a heat source to selectively melt the powder and create the structure layer by layer. However, during the processing, imperfections can occur. The spattering, accumulation of powder particles, and denudation effects lead

The geometrical characteristics of the weld end crater are commonly used as a means of validating numerical results in welding simulations. In this paper, an analytical model is developed for calculating the cooling stage of the welding process after the moving energy source is turned off. Solutions for various combinations of heat sources and heated bodies are found. It is shown that after turning

The present paper deals with short-pulse laser welding of copper and aluminum alloys in dissimilar configuration. In particular, a 100 W nanosecond-class pulsed fiber laser is exploited as a source for welding lap-joints both with linear and spt strategy. The investigation is aimed at understanding the role of the main process parameters, such as pulse shape, duration and energy, peak power, and welding

Laser polishing of metals consists of irradiating the part's surface with a laser beam, thus generating a molten layer that is redistributed and resolidified to create a surface with reduced roughness. However, the process is also characterized by an instantaneous formation of heat-affected zones with consequent microstructural changes that influence the mechanical properties. In order to understand