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Titanium is widely acknowledged as a challenging metal due to its inherent characteristics. Manufacturers often encounter challenges such as tool wear, reduced tool lifecycle, and increased cutting heat when working with Ti64. This research investigates the cutting characteristics of additively manufactured (AMed) Ti64 under dry cutting, Minimum Quantity Lubrication (MQL), Cryogenic Carbon dioxide (CO2), and a hybrid approach combining MQL and CO2 conditions. Surface roughness, flank wear, temperature, chip morphology, and microhardness were analyzed to assess the impact of cooling strategies. Results indicate that the hybrid approach outperforms individual methods, showing superior surface finish and reduced tool wear. Machined Surface roughness (Ra) measurements reveal a substantial improvement in the hybrid condition, reducing Ra values by 62.44–67.02%, 35.65–41.38%, and 18.68–27.59% compared to dry, MQL, and CO2. Tool wear assessments exhibit significantly lower flank wear values in the hybrid condition, emphasizing the synergistic benefits of lubrication and cryogenic cooling. This research provides valuable insights into tailoring cooling strategies for optimal precision in machining AMed-Ti64 material, which is crucial for achieving high-quality manufacturing outcomes.

Machine learning (ML) is a subfield of Artificial Intelligence (AI) that uses data, learns the hidden pattern from the data, and makes predictions for future instances with greater accuracy and prediction capabilities, not hallucination (overfitting) with the current data. The application of ML is quite popular in the machining sector because the ML models can be used to predict tool wear, surface roughness and other important machining aspects. With this aim, the present work evaluates the tool wear and class separation by predicting the variation of flank wear (Vb) as a test dataset. A predictive model is proposed for utilizing minimum quantity lubrication (MQL), cryogenic, and MoS2+MQL conditions. Predictions are made using several machine learning (ML) methods, including linear regression, support vector machine, random forest, and multilayer perceptron. The study's findings show that Multi-layer perceptron (MLP) is superior to other methods in classification, with a prediction accuracy of over 95% on average across both training and testing datasets. Even with limited information, the proposed method can help classify situations and recommend the best course of action for machining.

The present article describes a new and innovative method of producing an inseparable joint with the use of expansion jaws. The effect of jaw tool geometry on the reaction forces and ultimate strength of an inseparable joint formed on a prototype stand was analyzed. The results are also compared of joints produced by jaws with single movement method and with complex movement method. The tool responds with bending and pressing one part into the other, which results in their permanent connection. In the tests, differentiation was introduced with regard to the height of the applied force to the collar of the connection pipe. A novelty is also a solution based on a complex, parameterized trajectory of the stamp movement consisting of horizontal and vertical displacements. This paper presents the tests of the joints formed at the stand. The new approach described in this article has resulted in a joint strength increase of approximately 30% using the innovative complex jaw movement of the biaxial clinching process. A joint tensile strength close to 1000 N was achieved.

In the present study, functionally graded Al6061 composites reinforced with boron carbide (B4C), silicon carbide (SiC), and alumina (Al2O3) were prepared using the stir and centrifugal casting techniques. Arc-shaped functionally graded metal (FGM) specimens were treated with a hot-rolling process to enhance their mechanical properties and obtain laminated plates. Then, the impacts of ceramic reinforcements on the density, microhardness, tensile strength, and ballistic resistance of FGMs were studied. Moreover, the microstructural properties of the specimens were analyzed to elucidate the particle gradient from the inner to the outer surface. As a result, the microstructure observations revealed that the ceramic particles are dispersed from the inner to the outer periphery of the FGMs with centrifugal acceleration. A more homogeneous particle distribution was obtained in B4C-reinforced FGM compared to those of SiC and Al2O3. The hot-rolled FGM specimen reinforced with B4C offered the lowest density. The microhardness was improved by 32% and 30.4% in the inner to outer regions of the SiC- and Al2O3-reinforced FGMs, respectively, while it was improved by 22.6% in B4C-reinforced FGM. On the other hand, the tensile strength and elongation of the B4C-reinforced FGM specimen were better than those of the SiC- and Al2O3-reinforced FGMs. In addition, the highest ballistic protection was achieved with B4C-reinforced laminated FGM at an impact speed of 664.25 m/s with a penetration depth of 14 mm, while the impact speeds of SiC- and Al2O3-reinforced FGMs were 500.88 and 435.23 m/s, respectively.

Additive manufacturing technologies have emerged as the promising alternatives of conventional manufacturing techniques. Conventional manufacturing techniques involves cutting and removal of material by mechanical procedures to achieve final product. Whereas, discrete chunks of material in any form are combined point by point and layer by layer for the fabrication of final product in additive manufacturing processes. Numerous advantages and inefficiencies of these manufacturing techniques are reflected in factors such as the design, fabrication, material properties and working condition etc. Therefore, development of a production technology by combining the benefits of both conventional and additive techniques is significantly important. “Hybrid Manufacturing” jointly apply additive and conventional production methods to attain final products. Hence, this short overview covers the operation aspects of both additive and subtractive manufacturing of metallic materials.

Selective laser melting (SLM) has been considered as a well-researched technology used to produce near net shape metallic components with superior mechanical and physiochemical characteristics. Recently SLM has recently been used for the production of components made by high-performance alloys such as Titanium and Nickel. However, the microstructural and physical anisotropy along with the defects have negative impact on the performance and behavior of SLM-produced alloys. Therefore, to improve the material characteristics, extra attention must be paid to the source(s), identification, and removal of these deviations. Thermal heat treatments are often considered as an effective approach to deal with aforementioned issues. stress-relieving, quenching/hardening, annealing/recrystallization, and thermo-mechanical heat treatments are among prominent procedures adopted for the post processing of SLM fabricated metallic components and hence considered in this article. Since these procedures have substantial impact on the microstructure and mechanical behavior therefore an assessment of their influence and resulting changes is significantly important. Therefore, this short review provides the said knowledge on thermal treatments used to improve the SLM fabricated titanium and nickel-based alloys. This review can significantly help in designing and selecting appropriate post processing thermal treatments keeping in mind the expected outcome.

Powder bed fusion based additive manufacturing techniques involve melting or sintering of powder particles via laser beams to join them in order to attain desired shapes. This study aims to provide basis for material constitutive parameters of widely used aluminum alloy AlSi10Mg alloy. Initially, tensile samples of AlSi10Mg alloy samples were manufactured by using SLM technology. Afterwards, through quasi-static and high temperature tensile tests, an attempt has been made to determine the Johnson–Cook material model of AlSi10Mg. in order to conduct quasi-static tensile tests, strain rates of 10−3 s−1, 10−2 s−1 and 5 × 10−2 s−1 were considered and tests were conducted at ambient temperature. Whereas, for high temperature tensile tests 24, 150, 300 °C temperature values were considered at the reference strain rate value of 10−3 s−1. The numerically simulated tensile results achieved by using the established Johnson–Cook model were then compared with experimental results. It was observed that the maximum error between the test and simulation results was around of 7.5%. The error percentage is well within the acceptable, thus proving the accuracy of the established material model.

Selective laser melting (SLM) is one of the appreciable technologies that is directly used to manufacture the intricate and highly accurate parts within short period of time. However, the involvement of various parameters in SLM process is gaining more and more attention of the scientific community. In this work, the research efforts have been made to emphasize on the effects of one of the prominent parameters of SLM process i.e., layer rotation on the microstructure, grain size, surface topography, residual stresses and mechanical behaviour of selective laser melted Al-Si-10Mg alloy. The standard benchmark components were fabricated by varying the layer rotation values at three different angles i.e., 0°, 45° and 90°. The result of microstructural analysis (using EBSD, SEM and XRD) revealed that the Al-Si-10Mg produced the cellular structure having less pores and defects at 90-degree layer rotation angle. The grain size, residual stresses and surface roughness (77.02%) values were also reduced with increase in layer rotation angle values. Furthermore, the micro-hardness (upto 19.6 %), tensile strength, %elongation (87.29 %) and relative density values were significantly enhanced at higher angle of layer rotations mainly due to the reduction in porosity and better interlayer metallurgical bonding.

The article deals with the measurement of micro-hardness of the track by the action of ultrasonic excitation of pulsating water jet. The cumulative effect of liquid matter in the form of droplets concentrated in waveform measurements was provided in horizontal and vertical direction to material core (AISI 304). The material was subjected to pressures of p = 40, 50 and 60 MPa with the actuator working at a frequency of 20,14 kHz and traverse speed v = 1,1 mm/s, v = 0,80 mm/s and v = 0,30 mm/s respectively. The micro hardness measurement was carried out after machining it by pulsating water jet. The values were recorded in the zone located transversally under the trace to the depth of 1,5 mm with 0,1 mm distance between successive points. It was found that the deformation of material was ascertained from the boundary to the outer environment created by pulsating water jet to the inner core of the material. The results indicate that the pressure was the most influential parameter, which was responsible for the deformation strengthening of the material.

The poor fatigue strength of Ti-6Al-4V ELI is a main cause of failure in structural implants. In this work, Ti-6Al-4V ELI was subjected to β-solution treatment to obtain martensite microstructure and further subjected to −196 °C for 24 h. Significant improvement in high cycle fatigue performance of martensite Ti-6Al-4V ELI was observed on exposure to cryogenic cycle. Resistance to fatigue crack growth of alloy was augmented in martensite structure as compared with mill annealed sample and the same was retained even after exposure to cryogenic treatment. The variation observed in fatigue behavior due to cryogenic treatment was correlated with fractography and metallurgical investigations. Improvement in high cycle fatigue performance can be attributed to a combined effect of a decrease in the size of prior β grain, formation of massive α patch and its subsequent transformation into ultra-fine α and β during the soaking period at −196 °C.

Hole quality in drilling is considered a precursor for reliable and secure component assembly, ensuring product integrity and functioning service life. This paper aims to evaluate the influence of the key process parameters on drilling performance. A series of drilling tests with new TiN-coated high speed steel (HSS) bits are performed, while thrust force and torque are measured with the aid of an in-house built force dynamometer. The effect of process mechanics on hole quality, e.g., dimensional accuracy, burr formation, surface finish, is evaluated in relation to drill-bit wear and chip formation mechanism. Experimental results indicate that the feedrate which dictates the uncut chip thickness and material removal rate is the most dominant factor, significantly impacting force and hole quality. For a given spindle speed range, maximum increase of axial force and torque is 44.94% and 47.65%, respectively, when feedrate increases from 0.04 mm/rev to 0.08 mm/rev. Stable, jerk-free cutting at feedrate of as low as 0.04 mm/rev is shown to result in hole dimensional error of less than 2%. A low feedrate along with high spindle speed may be preferred. The underlying tool wear mechanism and progression needs to be taken into account when drilling a large number of holes. The findings of the paper clearly signify the importance and choice of drilling parameters and provide guidelines for manufacturing industries to enhance a part’s dimensional integrity and productivity.

Clinching is a technique for joining metal sheets without the use of welds or screws. This method of joining uses only the energy of the joining process and no consumables to achieve local deformation of metal pieces. It is also a straightforward method for attaching metal sheets with thicknesses between about 0.5 and 3mm, and the maximum joint thickness is about 6mm. Clinching is often reserved for high-volume, low-demand applications like home appliances, HVAC parts, and automobile assemblies. This article describe clinching of cylindrical surfaces on prototype stand with different tools. Explanation of clinching and description of prototype stand for joining cylindrical surfaces. The differences od tooling is made by change of shape and size and analysis samples were made from aluminum 3003. The connection was studied by put into shear strength test and endurance test strength and check under the microscope thickness of the deformed walls.

The advantages of additive manufacturing (AM) over conventional manufacturing techniques, such as the ability to build parts with complicated geometry, have led to a rise in its applications in recent years. However, the mechanical and tribological qualities of an additively manufactured (AMed) parts are distinct from those of a conventionally made components because of the layer-by-layer nature of AM process. However, there is a need to machine these complex geometries of AMed components to achieve the desired final dimension and surface finish. Therefore, this study investigates the impact of four environmental regimes (dry, flood, MQL, and N-MQL) on the metal cutting of AMed 316L stainless steel specimen, with a focus on the efficacy of N-MQL lubrication containing rice bran oil + carbon dots (CDs) particles. Responses measured include cutting temperature, surface roughness (Ra), tool wear, microstructure, and micro-hardness. Outcomes show that N-MQL outperforms other cutting regimes, offering enhanced machining performance and surface quality, making it a crucial choice for AMed specimens.

The paper presents evaluation of the surface topography obtained after turning of AISI 1045 steel with the use of cemented carbide tools diversified in terms of applied titanium-based coatings. During the research, three types of coatings deposited with the PVD method on a P25 sintered carbide insert were compared: nitride-titanium TiN, nitride-aluminum-titanium TiAlN and carbon-titanium TiC in a wide range of variable cutting speeds 125 - 325 m/min and variable feeds 0.05 - 0.25 mm/rev. The quality of the machined surface was assessed on the Sensofar S neox System optical profile meter using the confocal method. The paper presents the results of 3D parameters, contour maps, isometric views and material ratio curves. The surface topography analysis showed that for the TiAlN coated insert, lower surface roughness parameters were observed in the range of lower cutting speeds and higher feeds, while for higher cutting speeds, lower values of the selected 3D parameters were found for the insert with TiC coating. For the insert with TiC coating, the most even distribution of the valleys and ridges of the machined surface roughness was also observed. The research results determined the range of cutting parameters that allow the selection of the appropriate type of titanium-based coating when machining AISI 1045 steel.

This study describes the surface topography of the 17-4 PH stainless steel machined under dry, wet and near-dry cutting conditions. Cutting speeds of 150–500 m/min, feeds of 0.05–0.4 mm/rev and 0.5 mm depth of cutting were applied. The research was based on the ‘parameter space investigation’ method. Surface roughness parameters, contour maps and material participation curves were analysed using the optical Sensofar S Neox 3D profilometer and the effect of feed, cutting speed and their mutual interaction was noticed. Changes in chip shape depending on the processing conditions are shown. Compared to dry machining, a reduction of Sa, Sq and Sz parameters of 38–48% was achieved for near-dry condition. For lower feeds and average cutting speeds valleys and ridges were observed on the surface machined under dry, wet and near-dry conditions. For higher feeds and middle and higher cutting speeds, deep valleys and high ridges were observed on the surface. Depending on the processing conditions, different textures of the machined surface were registered, particularly anisotropic mixed, periodic and periodically determined. In the Sa range of 0.4–0.8 μm for dry and wet conditions the surface isotropy is ~20%, under near-dry conditions it is ~60%.

The rapid growth of a modern industry results in a growing demand for construction materials with excellent operational properties. However, the improved features of these materials can significantly hinder their manufacturing, therefore they can be defined as hard−to−cut. The main difficulties during the manufacturing/processing of hard−to−cut materials are attributed to their high hardness and abrasion resistance, high strength at room or elevated temperatures, increased thermal conductivity, as well as their resistance to oxidation and corrosion. Nowadays the group of hard−to−cut materials includes the metallic materials, composites, as well as ceramics. This special issue, “Advances in Hard−to−Cut Materials: Manufacturing, Properties, Process Mechanics and Evaluation of Surface Integrity” provides a collection of research papers regarding the various problems correlated with hard−to−cut materials. The analysis of these studies reveals primary directions regarding the developments in manufacturing methods, and the characterization and optimization of hard−to−cut materials.

The objective of the investigation was analysis of the wear of milling cutters made of sintered carbide and of boron nitride. The article presents the life period of the cutting edges and describes industrial conditions of the applicability of tools made of the materials under investigation. Tests have been performed on modern toroidal and ball-end mill cutters. The study has been performed within a production facility in the technology of high speed machining of 55NiCrMoV6 and X153CrMoV12 hardened steel. The analysed cutting speed is a parameter which significantly influences the intensity of heat generated in the cutting zone. Due to the wear characteristics, two areas of applicability of the analysed tools have been distinguished. For v c ≤ 300 m/min, sintered carbide edges are recommended; for v c > 500 m/min, boron nitride edges. For 300 ≤ v c ≤ 500 m/min, a transition area has been observed. It has been proved that the application of sintered carbide edges is not economically justified above certain cutting speed.