Additive manufacturing through laser powder bed fusion (LPBF) enables the production of geometrically complex nickel-based superalloy components. However, it results in poor surface quality, partially melted powder particles, and surface irregularities, that limits their performance in critical applications. This study investigates nanosecond laser polishing as an advanced post-processing technique for improving the surface quality of LPBFmanufactured Haynes 230, a high-temperature Ni-Cr-W superalloy. Eighteen LPBF-manufactured samples were polished using a nanosecond pulsed fiber laser while systematically varying laser power (25-170 W), pulse duration (2611420 ns), pulse frequency (150-400 kHz), and scanning speed (900-2400 mm/s) to establish a comprehensive processing window. Surface roughness parameters (arithmetic mean height Sa and maximum height Sz) were measured using confocal microscopy, while remelted layer thickness, microstructure, and microhardness were analyzed through metallographic observations and Vickers microhardness testing. Laser polishing significantly improved the surface finish, achieving a maximum reduction in Sa of 90.9%, decreasing from 18.98 & micro;m to 1.72 & micro;m under optimal parameters of 110 W, 150 kHz, 1420 ns, and 900 mm/s. The remelted layer thickness ranged from 24 to 129 & micro;m, increasing with higher laser power and lower scanning speeds. Excessive power levels (170 W) resulted in subsurface cracking and porosity, whereas optimal conditions produced a smooth, crack-free surface and average microhardness of remelted layer ranging approximately from 274 to 383 HV. This work provides the systematic investigation of nanosecond laser polishing of LPBFmanufactured Haynes 230 and establishes practical correlations between laser parameters, energy intensity, and resulting surface morphology. The findings provide valuable guidelines for optimizing laser-based surface finishing of nickel-based superalloys used in high-temperature applications.

While the machining of Inconel 718 has been widely studied, its cast counterpart Inconel 713LC remains underexplored, despite its relevance in high-temperature aerospace and energy components. This work presents a comprehensive investigation of dry milling behavior in Inconel 713LC, focusing on the interplay between tool wear, cutting forces, surface integrity, and chip formation across a broad range of cutting parameters. A stable process window was identified: 30–50 m/min cutting speed and 0.045–0.07 mm/tooth feed, where surface roughness remained below Ra 0.6 µm and tool life exceeded 10 min. Outside this window, rapid thermal and mechanical degradation occurred, leading to flank wear beyond the 550 µm limit and unstable chip morphology. The observed trends align with those in Inconel 718, allowing the cautious transfer of established strategies to cast alloys. By quantifying key process–performance relationships and validating predictive models for tool life and cutting forces, this study provides a foundation for optimizing the dry machining of cast superalloys. The results advance sustainable manufacturing practices by reducing reliance on cutting fluids while maintaining surface and dimensional integrity in demanding applications.

High-velocity oxyfuel (HVOF) coatings are used to protect components from corrosion and wear at higher temperatures and from wearing out after a certain period of time. Hence, to enhance the life of components, further recoating is required, but removing the older coating is a challenging task due to its high hardness. Thus, this research work studied the electrolytic dissolution process of removing WC-CoCr 86/10/4 HVOF coatings and found that at a voltage of 3 V, the coating was not removed, but at a slightly higher voltage of 6 V, the coating was removed completely. When the voltage was 12 V, the surface was damaged, and corrosion also occurred. A combination of tartaric acid (C4H6O6), sodium bicarbonate (NaHCO3), and water was used as an electrolyte. By using a combination of a voltage of 4.5 V, a current of 1.6 A, and an electrode distance of 55 mm, the coating was completely removed after 10 h, with negligible attacks on the base material. Where the corrosion of the base material is unacceptable, voltages in the range of 4 to 6 V are recommended. If parts have coatings on all surfaces, a voltage within the range of 6 to 12 V can be recommended. The coating from tab SB-002JI-5 TOOLOX-11 and hexagonal mandrel SB-00EA-1 160 TIS was also removed successfully.

This study addresses a critical issue in mass-producing gearbox housing MQ200GA at Škoda Auto a.s. The combination of SW ProCAST simulations and metal 3D printing (laser powder bed fusion—L-PBF) overcomes challenges posed by full mold printing. Instead, the authors adapt the conformal cooling design, introducing specific channel paths in 3D printed inserts. Exploring conformal cooling (CC) and conformal cooling channels (CCC), the study focuses on stabilizing the temperature field, optimizing heat exchange, and improving part quality. Real production implementation successfully eliminates shrinkage porosity, demonstrated in a test series of 8 000 castings. Challenges with the unregulated cooling circuit temperature are acknowledged, along with a close correlation between simulations and real-world measurements. The feasibility of 3D-printed inserts in molds is confirmed in active production, producing over 43 000 castings. This experiment showcases the benefits of metal 3D printing in high-pressure die casting (HPDC). Despite challenges, the authors successfully modified serial tools for aluminum HPDC, deploying test 3D-printed inserts with CC directly into real production. This risk pays off, providing valuable insights for researchers and industry experts considering a similar approach.

One completely new geometry and two modified chip breaker geometries were designed to increase the stability and reliability of the stainless steel dry drilling process. Experiments were performed and the results of individual tools were compared with a conventional solid carbide twist drill Guhring Ratio with a diameter of 5 mm. A matrix of three feed rates (0,03-0,07 mm/rev) and three cutting speeds (20-30 m/min) was designed for the cutting conditions. Precipitation-hardenable stainless steel 17-4 PH was chosen as a workpiece. During the experiment, the values of thrust force, spindle torque, temperature of the tool, surface roughness, chips morphology and chips division were recorded and compared with the reference tool.The results showed that compared to the reference tool A, the tool C -a multipoint drill with grooves through the cutting edge achieve approximately 4 % lower values of thrust force and 10-15 % lower values of spindle torque. Tool D with a step drill geometry achieve approximately 17 % lower values of thrust force and 10-15 % lower values of spindle torque and there is no chip clogging in the flute with C and D geometries. This effect is confirmed by the fact the spindle torque basically does not increase with the increasing depth of drilling. Tool B - new designed geometry achieve approximately 15 % lower values of thrust force and similar spindle torque values as the reference drill A. Tool temperature is a very important factor when dry drilling. Compared to the reference drill A, it was possible to achieve the tool temperature reduction of 20 % with the new geometry B, as well as with the multipoint drill C reduction by 26 % and with the step drill D reduction approximately by 30 %. All the modified drills also achieved a reduction in the surface roughness of the drilled holes. By 17 %, 35 % and 48 % lower surface roughness Ra was achieved with drills B, C and D. Chip morphology was significantly different for the tested drills. Conventional twist drills A and B generated helical short chips. While C and D twist drills with divided cutting edges generated ribbon snarled chips. Thanks to the reduction of cutting forces and temperature, it is possible to stably operate the drilling process with a higher cutting speed and feed rate, which leads to an increase in the efficiency and reliability of the machining process.

This paper aims at an in-depth and comprehensive analysis of mechanical and microstructural properties of AISI 316L austenitic stainless steel (W. Nr. 1.4404, CL20ES) produced by laser powder bed fusion (LPBF) additive manufacturing (AM) technology. The experiment in its first part includes an extensive study of the anisotropy of mechanical and microstructural properties in relation to the built orientation and the direction of loading, which showed significant differences in tensile properties among samples. The second part of the experiment is devoted to the influence of the process parameter focus level (FL) on mechanical properties, where a 48% increase in notched toughness was recorded when the level of laser focus was identical to the level of melting. The FL parameter is not normally considered a process parameter; however, it can be intentionally changed in the service settings of the machine or by incorrect machine repair and maintenance. Evaluation of mechanical and microstructural properties was performed using the tensile test, Charpy impact test, Brinell hardness measurement, microhardness matrix measurement, porosity analysis, scanning electron microscopy (SEM), and optical microscopy. Across the whole spectrum of samples, performed analysis confirmed the high quality of LPBF additive manufactured material, which can be compared with conventionally produced material. A very low level of porosity in the range of 0.036 to 0.103% was found. Microstructural investigation of solution annealed (1070 °C) tensile test samples showed an outstanding tendency to recrystallization, grain polygonization, annealing twins formation, and even distribution of carbides in solid solution.

Laser polishing process is a promising technology for post-processing of complex parts prepared by additive manufacturing. In this study, the nanosecond laser polishing process was employed to improve a surface roughness of SLM (selective laser melting) prepared 316 L stainless steel with different part orientation (0°, 15°, 45°, 75° and 90°) during construction. Afterwards, the changes of surface topography, morphology and the cross-sectional microstructure before and after laser polishing were investigated. Additionally, the study also focusses on the process of 3D printing, especially on material porosity after sintering process. The results obtained from computer tomography showed that the samples were well prepared, with porosity below 0.019%. After laser polishing, surface roughness represented by Sa and Sz values was reduced for all printed samples regardless to their construction angle with similar laser and scanning parameters. The maximum roughness reduction reaches more than 90% (from Sa = 9.8 µm to Sa = 0.77 µm). Moreover that, other surface analysis established the best conditions for laser polishing. Finally, from the cross-section, the microstructure analysis was done and thickness of melted layer, heat-affected zone followed by microhardness measurement was estimated. Except of one applied condition, all samples were very homogenic with no damages in intersection layer. Simultaneously, there were no changes in microhardness after laser process observed.

Strain-controlled Low-Cycle Fatigue tests (LCF) and Thermo-Mechanical Fatigue tests (TMF) were performed on a low-alloy martensitic steel in the temperature range between 300 °C and 600 °C, with and without a strain dwell. TMF tests were performed for three different phase angles between thermal strain and mechanical strain: as in-phase, as out-of-phase and as counter clockwise-diamond. The results show that the phase angle that is employed has a significant influence on the dominant damage mechanism and on the observed lifetime. Finally, a modified damage model is proposed in order to take into account the effect of the phase angle.

Main goal of this study is to describe and design manufacturing system which is using Additive manufacturing technology for production of semi-finished products and conventional machining technology for finishing operations, then demonstrate requirements of such production on simulation model on production planning and then analyze and summarize the outputs of the production model. The model is made with aid of modern Digital Factory tools. The main purpose of the model is to provide a complex tool for this study in order to analyze and optimize the fictive production system in needed range and complexity. The topic of Rapid Prototyping and Additive manufacturing technologies is very recent topic in industry. But still, there are only few examples of production systems, which are really using Rapid Prototyping technologies as a part of the production or production line. The advantage of these technologies is their versatility, but on the other hand, as a part of production system, they can have different demands on for example production planning, area consumption or maintenance, that can affect whole production system.

This study deals with surface integrity expressed in terms of stress state as well as microstructure alterations after turning a duplex stainless steel. Residual stresses and the presence of strain-induced martensite are studied as functions of the rake angle. Residual stresses of surface and sub-surface layers were determined by the use of the X-ray diffraction and hole-drilling techniques. X-ray diffraction enables us to distinguish between residual stresses in each phase separately, which is not possible when the hole-drilling method is applied. Furthermore, alterations in the near surface region are also analysed by the use of the magnetic Barkhausen noise and metallographic observation.

Creep feed grinding is one of the progressive machining technologies. This method ranks among roughing technologies where the goal is to remove as much material as possible in the shortest time. Creep feed grinding has been developed due to hard-machining materials that can not be effectively machined in another way (for example nickel alloys used for turbine blades in aviation engines). The development of a new machining method goes hand in hand with the development of machining tools, in this case grinding wheels. The grinding wheel is very different from the classic tool, so the development is adapted to varios requirements. In creep feed grinding the higher porosity of the wheel is important due to the possible distribution of the cooling medium to the cutting point. However, considerable attention is paid to the shape of the grain itself, or to the self-sharpening ability of the grinding wheel. The development of new materials has come so far that today we can talk about defined blade geometry, which was not possible with classical materials.

This paper deals with the dimensional analysis of the turboprop aircraft engine radial compressor wheel. The radial compressor wheel is very complex component. This part is manufactured by turning and five-axis milling technology. Due to the high stress of this part in service life, the residual stress in the surface layer is important. Desirable are the compressive stress levels to prevent cracks. For this reason, research is being carried out on technologies that influence the surface layer. They are the finishing technologies vibrational tumbling and superfinishing. The article describes the method used to measure the thickness variation of blade of the compressor wheel after vibrational tumbling and superfinishing. In terms of shape complexity a coordinate measuring machine with a rotary table was used.

The article deals with testing of the resistance against Foreign Object Damage (FOD) on leading edges of blisks (blade disks) in turboprop engines made of Ti6Al4V alloy. Such damage can occur during operation, when rapidly rotating compressor parts on the engine intake are exposed to foreign particles. E.g. operation of small passenger aircrafts in desert areas, where large amounts of foreign particles occurs in the atmosphere. The paper describes the development of method for testing the resistance of the leading edge of the blades against FOD in order to mimic the conditions of operational damage. Further it quantifies potential benefits of modification in the geometry of the blisk leading edge and compares results of FOD resistance of sharp leading edge and modified geometry. Results of metallographic analysis for deformed areas near the FOD on Ti6Al4V alloy are also presented.

The goal of this contribution was to describe parameters of surface integrity of two machined materials; austenite and duplex stainless steel. Residual stresses and presence of straininduced martensite were studied as a function of the side rake angle. Residual stresses of surface and sub-surface layers were determined using X-ray diffraction techniques and hole-drilling method. By using X-ray diffraction, it is possible to determine residual stresses in each phase separately, in comparison with hole-drilling method. The presence of strain-induced martensite was investigated using Barkhausen noise and optical microscope.

From the viewpoint of residual stresses and microstructure of ground surface, Inconel 713 superalloy is an attractive material since it is frequently used in high temperature gas turbine applications where residual stresses are relevant for service life. The goal of this contribution is to find whether there exists a relation between grinding parameters and final surface integrity parameters such as residual stresses, roughness, crystalitte size, and generally, microstructure. Highly productive creep feed grinding has been applied to produce both simple flat areas and complex fir three blade root. It has been found that the used grinding method lead to very thin deformed layer on the surface with compressive residual stresses and fine crystallites. Moreover, the detailed analyses have been carried out in order to pinpoint plausible reasons behind crack origination.

The contribution is dedicated to surface integrity assessment of components from the point of view of residual stress profile after machining and finishing technologies. Residual stresses play the key role for dynamic life and service reliability of the part, especially rotating aircraft airfoils made of titanium and nickel base alloys. Except a brief summary of measurement methods practical experience with application of Beam deflection method combined with electrolytic etching is published. Specific measurement results for real aircraft Ti6Al4V airfoils and Ti6Al4V plates following its manufacturing technology are the subject of experimental part.

The goal of this contribution was to describe the microstructure and properties changes of difficult to cut materials after turning. Surface residual stresses, roughness, microstructure of AISI 304 type stainless steel were studied as a function of side rake angle o. Residual stresses and phase composition of surface and sub-surface layers were determined using X-ray diffraction techniques. The presence of strain-induced martensite was investigated using Barkhausen noise, optical microscope, and microhardness measurement.

Jan Brajer, Jan Mádl, Roman Švábek, Zdeněk Pitrmuc ,Danijela Rostohar, Pavel Zeman , José Luis Ocaña Department of Machining, Process Planning and Metrology, Czech Technical University in Prague, Technická 4, 166 07 Prague 6 Dejvice, Czech Republic E-mail: J.brajer@fs.cvut.cz HiLASE Centre, Institute of Physics ASCR, Za Radnicí 828, 25241 Dolní Břežany, Czech Republic E-mail: brajer@fzu.cz Centro Láser UPM (Universidad Politécnica de Madrid) Ctra. de Valencia, km. 7,3. 28031 Madrid. Spain. E-mail: jlocana@etsii.upm.es

1. FORMAL STRUCTURE The reviewer evaluates total formal level of the paper, use of the uniform example and logic structure of the paper including pictures, graphs and tables and their explanation. A – Excellent content of the paper B – Very good content of the paper C – Good content of the paper D – Satisfactory content of the paper E – Sufficient content of the paper F – Failed content of the paper Comments: . The transition from compressive to tensile stress occurs transitions from compressive to tensile stress occur