Cutting & Tools in Technological System

COATED DIAMONDS AND DIAMOND COATINGS (A REVIEW OF CURRENT DEVELOPMENTS)

2026-04-15T10:23:30+03:00

Recent studies have shown the effectiveness of coating diamond grains with thin layers of titanium and nickel to provide a tight interface with the nickel matrix. Wetting of diamond and nickel is improved by coating diamond particles with thin layers of titanium and nickel. Titanium carbide formed between Ti-coating and diamond provides stronger interfacial adhesion force compared to diamond micropowder with Ni-coating. To improve the thermal properties of diamond/metal composites, a metal carbide layer is needed that combines both the crystal structure and the heat transfer of heterogeneous interfaces. In modern research in coatings, in addition to TiC, attention is paid to other carbides: B₄C, V2C and VC, as well as chromium carbides. A separate direction is oxide coatings on diamonds. The mechanism of diamond protection in this direction is the predominant oxide donor behavior of Mo–B–C coatings for the formation of a stable oxide layer on the diamond surface. Diamond films with three different grain sizes were grown on the surface of a titanium alloy by high-temperature chemical vapor deposition (HFCVD). The corrosion resistance of nanocrystalline diamond (NCD) films is clearly higher than that of microcrystalline diamond (MCD) films. But cutters with intact MCD coating demonstrate the longest service life. Attention has been paid to coatings applied to hard alloys and steels, with researchers mainly focusing on coatings containing titanium, namely TiAlN, TiN/CrN and Al2O3/TiO2.

SUPPLIER SEGMENTATION BASED ON PERFORMANCE DATA USING HIERARCHICAL CLUSTERING

2026-04-15T12:18:15+03:00

In many manufacturing environments, procurement managers must regularly compare suppliers with significantly different performance profiles, which makes structured evaluation essential. Grouping suppliers with similar performance characteristics can make procurement decisions more transparent and easier to justify in practice. However, supplier performance is typically described by multiple evaluation criteria measured on different scales, and these performance characteristics may change over time. For this reason, analytical approaches are required that can handle both the multidimensional nature of the data and the changes in supplier performance over time. In this paper, an adaptive supplier segmentation approach is developed based on hierarchical clustering techniques. Supplier performance is evaluated using multiple operational criteria, including quality rate, on-time delivery, unit price, lead time, complaint frequency, and operational flexibility. After applying min–max normalization and weighted performance evaluation, supplier similarities are calculated using Euclidean distance, and hierarchical clustering methods are applied to identify homogeneous supplier groups. Several linkage strategies are compared, and the clustering quality is assessed using internal validation indices such as the Silhouette, Davies–Bouldin, Calinski–Harabasz, and Dunn indices. The empirical analysis is conducted on a dataset containing 15 suppliers observed in two consecutive evaluation periods. The results indicate that hierarchical clustering can reveal interpretable supplier groups with clearly distinguishable performance profiles. A comparison of clustering structures across consecutive periods also shows that supplier segmentation evolves as new performance data become available.

INVENTORY PLANNING FOR 3D-PRINTED SPARE PARTS UNDER UNCERTAIN DEMAND

2026-04-15T14:16:52+03:00

In recent years, additive manufacturing technologies have increasingly appeared in industrial spare parts logistics systems. Instead of maintaining large inventories of finished components, companies can increasingly rely on digital inventories and produce spare parts on demand using 3D printing. This shift creates new decision-making challenges related to the management of raw printing materials and the planning of production under uncertain demand. This paper proposes a two-echelon newsvendor model for inventory planning in additive manufacturing-based spare parts supply systems. In the proposed framework, the first decision stage determines the quantity of raw printing material to be stocked before demand realization, while the second stage determines the number of spare parts produced in response to stochastic customer demand. The model captures the trade-offs between material procurement cost, inventory holding cost, and shortage penalties. The mathematical formulation is developed as a two-stage stochastic optimization problem. Numerical experiments are conducted to analyze the relationship between raw material inventory levels and expected system cost. The results show that the cost function exhibits a well-defined minimum and that the optimal material inventory level strongly depends on shortage cost parameters. Sensitivity analysis further demonstrates how shortage penalties influence optimal inventory decisions. The findings highlight the strategic role of raw material inventory in additive manufacturing supply systems and provide practical insights for companies adopting 3D printing technologies in spare parts logistics.

ANALYSIS OF THE INFLUENCE OF TECHNOLOGICAL PARAMETERS ON THE PROPERTIES OF DIAMOND-BEARING COMPOSITES USING 3D MODELING

2026-04-15T15:41:51+03:00

This paper presents a methodology for 3D simulation of the thermo-forced deflected mode in the sintering zone of diamond composite materials (DCM) and the grinding area, considering them as a unified system: "material to be machined – grain – metallphase – bond." The approach includes experimental studies of the 3D topography of interacting surfaces using laser scanning. A simulated 3D model of the system "diamond crystallites – metallphase – grain – bond" enables analysis of its behavior under various sintering and machining conditions, wheel performance parameters, grain anisotropy, and the presence or absence of cutting fluid. This methodology supports the development of an expert system for designing efficient, resource-saving combined processes for precision machining of superhard composite materials, with full consideration of their anisotropy.

IMPROVING THE EFFICIENCY OF USING DIAMOND GRINDING WHEELS ON THE ORGANIC BINDER BY CALCULATING THE RATIONAL STRUCTURE AND INTRODUCTION OF ULTRADISPERSED DIAMOND

2026-04-15T17:39:40+03:00

The article presents one of the options for developing scientifically based recommendations for choosing a rational combination of the strength of the binder, the size of the diamond grain, the concentration of diamond grains with the physical and mechanical properties of different types of binders in the manufacture of diamond grinding wheels. The conducted studies have shown the feasibility of using detonation nanodiamond powders as a modifier of the polymer binder. The introduction of nanopowder into the polymer leads to an increase in microhardness by 23%, and the recommended mass fraction of nanodiamond should be about 1% of the weight of the binder. It is possible to use such polymer compositions in the diamond layer of standard grades, which theoretically will increase their hardness due to constant thermal conductivity.

THE EFFECT OF MECHANICAL AND GEOMETRIC CHARACTERISTICS OF INHOMOGENEOUS REGIONS ON THE INTENSITY OF CRACK FORMATION DURING THE GRINDING OF PARTS MADE OF FUNCTIONALLY-GRADIENT MATERIALS

2026-04-15T17:59:59+03:00

The lack of research on the specifics of the initiation of grinding cracks and their development into main cracks depending on the design, technological, and structural inhomogeneities of the material of the products does not allow for the unambiguous application of existing recommendations for eliminating the defects in question. This work is devoted to investigating the influence of inherent inhomogeneities in the surface layer, their geometry, and mechanical characteristics in products made of functionally graded materials on the selection of technological conditions for defect-free machining of parts. It has been established that the magnitude of the stress intensity factors for inherent inhomogeneities formed in the surface layer of products made of functionally graded materials is influenced by the size and orientation of these defects, their depth of occurrence and mutual arrangement, and the magnitude of the heat flux during grinding. The geometry and properties of inclusions formed by previous operations in the surface layer can create conditions for both the inhibition and the development of grinding cracks. If the heat flux is directed parallel to the inclusion axis and a straight, thermally isolated crack, then when the linear thermal expansion coefficient of the inclusion is greater than that of the matrix, an increase in the stiffness of the inclusion leads to an increase in the stress intensity factors K_I (K_II=0) for various ratios of the thermal conductivity coefficients of the material components. This leads to the propagation of microcracks. Conversely, if the thermal expansion coefficient of the inclusion is lower than that of the matrix, a decrease in the stiffness of the inclusion leads to a decrease in the stress intensity factors K_I (K_II=0) for the same ratios of thermal conductivity coefficients, i.e., conditions favorable for the non-propagation of microcracks are present. Therefore, when determining defect-free grinding parameters, it is necessary, first and foremost, to establish the maximum permissible cutting depths. In doing so, it is also important to have information not only on the thermophysical and mechanical properties of the material and the presence of inhomogeneities in the surface layer, but also on its processing conditions.

EFFECT OF THE TURNING INSERT SHAPE AND FEED ON THE SURFACE PROFILE

2026-04-15T20:20:46+03:00

This study investigates the combined effect of cutting insert geometry and feed rate on surface roughness in turning of 42CrMo4 alloy steel. Controlled experiments were conducted on a CNC lathe using three insert geometries (C, D, and V types) and three feed rates (0.15, 0.25, and 0.35 mm/rev), while maintaining constant cutting speed and depth of cut. Surface characteristics were evaluated through quantitative roughness measurements and qualitative microscopic analysis. The results demonstrate that feed rate is the dominant factor influencing surface roughness, with increasing feed leading to a significant deterioration in surface quality, as reflected by higher Rz and Rt values. Insert geometry also plays a critical role: C and D inserts produce consistently lower roughness values, whereas the V insert results in inferior surface quality under identical cutting conditions. Notably, despite identical nose radii, substantial differences were observed between C and V inserts, highlighting the pronounced influence of edge geometry, particularly the end cutting edge angle. The findings indicate that conventional geometric models based solely on feed and nose radius are insufficient to accurately predict surface roughness. Instead, insert shape parameters must also be considered. This study contributes to improved understanding of the interaction between tool geometry and machining parameters and provides practical guidance for optimizing surface quality in turning operations.

AUTOMATED SYSTEM FOR CONTROLLING SURFACE ROUGHNESS PARAMETERS USING LASER TRIANGULATION

2026-04-16T18:49:58+03:00

The article discusses the development of an automated system for controlling the surface roughness parameters of parts, integrated directly into the machining process on CNC machines. The relevance of the study is due to the increasing requirements for the quality of surfaces that determine the operational characteristics of products, in particular wear resistance, tightness and strength of joints. The object of the study is the process of non-contact measurement of the surface microprofile by the laser triangulation method. The paper proposes a method for determining the microrelief parameters based on the analysis of the laser spot displacement on the CMOS matrix. To increase the accuracy, an algorithm for subpixel determination of the signal energy center and digital filtering using a Butterworth filter are used, which allows minimizing the impact of noise, vibrations and production interference. The results obtained confirm the effectiveness of the proposed approach and allow reducing the percentage of defects by 12–15%. The proposed system corresponds to the concept of Industry 4.0 and contributes to increasing the level of production automation.

EVALUATION OF MACHINABILITY BASED ON CUTTING FORCE AND SURFACE QUALITY CHARACTERISTICS USING THE TOPSIS METHOD

2026-04-19T14:54:38+03:00

The study proposes a multi-criteria machinability evaluation based on cutting forces, surface quality, and productivity characteristics obtained from CNC milling experiments. Three tool steels (1.2379, 1.2842, and ES Aktuell 1200) and four long-reach milling cutters were tested under controlled machining conditions. The experimental data set, including force components and surface roughness parameters, was analysed using the TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) method to integrate multiple performance indicators into a single metric, referred to as the Cutting Ability Index (CAI). The results show that the proposed approach enables the ranking of material-tool combinations and provides a more comprehensive interpretation of machinability compared to single-parameter evaluations. However, the resulting rankings are sensitive to the selection and balance of input criteria and, in certain cases, deviate from expected physical behaviour. This highlights the limitations of equally weighted multi-criteria approaches and underscores the importance of appropriate parameter selection and weighting. The study confirms that while TOPSIS can serve as an effective decision-support tool in machining analysis, its application requires careful methodological consideration.

INVESTIGATION OF ENERGY INPUT AND MACHINING EFFICIENCY AT ABRASIVE WATER JET CUTTING

2026-04-23T11:34:16+03:00

Abrasive waterjet machining is a widely used technology for cutting metal, ceramic and polymer sheets. Nowadays, it is becoming important that the applied technological parameters are efficient and economical. This requires the appropriate selection of the most important technological parameters. In this paper, we report on research in which the combined effect of technological parameters, i.e. the relationship between the input energy and the efficiency, was examined when machining three material qualities (metal, ceramic, polymer). The article examines the relationship between the depth of kerf and the amount of energy input by the jet and formulates conclusions regarding the machinability of different materials.

COMPARATIVE STUDY OF SURFACE HEIGHT AND GRADIENT PARAMETERS IN TURNING OF 42CRMO4 AND X5CRNI18-10

2026-04-23T12:01:28+03:00

This study presents a comparative investigation of surface topography in turning of two engineering materials, 42CrMo4 alloy steel and X5CrNi18-10 austenitic stainless steel. A full factorial experimental design was applied to evaluate the effects of cutting speed, feed, depth of cut, and material type on selected areal surface roughness parameters. The analysis focused on Sq, Sp, Sv, and Sdq, representing surface height and gradient characteristics according to ISO 25178. The results show a strong dependence of surface topography on material properties. The 42CrMo4 steel exhibited significantly higher roughness and steeper surface features compared to the stainless steel under identical cutting conditions. Increasing cutting speed led to a consistent reduction in all evaluated parameters, while feed rate primarily influenced the amplitude-related characteristics. The Sdq parameter showed lower sensitivity to cutting conditions but highlighted clear differences in surface slopes between the materials. The findings demonstrate that the combined evaluation of height and gradient parameters provides an effective approach for characterizing machining-induced surface features and supports improved selection of cutting conditions.

PROCESS PARAMETER OPTIMIZATION IN THE MACHINING OF FIBER-REINFORCED POLYMERS: A REVIEW OF METHODOLOGIES FROM TAGUCHI TO NEURAL NETWORKS

2026-04-23T14:19:35+03:00

The widespread adoption of Fiber Reinforced Polymers (FRPs), such as CFRP and GFRP, in weight-critical industries has necessitated highly precise secondary machining operations. However, the heterogeneous and anisotropic nature of these composites makes them susceptible to severe machining-induced defects, including delamination, matrix smearing, and rapid tool wear. To mitigate these issues, selecting and controlling optimal machining parameters (cutting speed, feed rate, and depth of cut) is critical. This paper comprehensively reviews the evolution of process optimization strategies in composite machining. It begins by examining established traditional statistical methods, including the Taguchi Method, Analysis of Variance (ANOVA), and Response Surface Methodology (RSM), which offer robust, data-efficient frameworks for linear process control. Subsequently, the paper explores the paradigm shift toward Artificial Intelligence (AI) and machine learning techniques, specifically Artificial Neural Networks (ANN), Genetic Algorithms (GA), and Fuzzy Logic systems. These data-driven approaches successfully overcome the limitations of traditional models by capturing complex, non-linear thermo-mechanical dynamics and resolving multi-objective conflicts. Ultimately, this review highlights that the future of zero-defect composite manufacturing lies in integrating these methodologies into intelligent hybrid models that bridge the gap between experimental efficiency and advanced predictive accuracy.

ANALYSIS OF FUNCTION-DEFINING 3D SURFACE PARAMETERS IN DIAMOND BURNISHING

2026-04-25T12:10:10+03:00

The tribological effects of diamond burnishing are investigated on EN AW 2011 aluminium alloy cylindrical surfaces. In engineering practice, the tribological behaviour of machined parts is often characterized using functional surface roughness parameters such as the Sk (core roughness depth), Spk (reduced peak height), and Svk (reduced valley depth) 3D roughness parameters. In the present study, the influence of various burnishing parameter settings is evaluated comprehensively through both their quantitative roughness values and the corresponding Abbott-Firestone material ratio curves. This combined approach enables a deeper understanding of how the burnishing process modifies the surface topography and, consequently, the tribological performance of the material under operational conditions.

QUALITY OF MACHINED SURFACES OF THIN-WALLED ELEMENTS OF PARTS UNDER THE ACTION OF REGENERATIVE VIBRATIONS DURING MILLING WITH END MILLS

2026-05-05T17:40:57+03:00

Monowheels, in which the disk and working blades constitute a single structure without detachable connections, are critically important components of new generation gas turbine engines for aviation and power engineering. The use of such structures allows to reduce the weight and increase the reliability of the units. However, errors in the shape of the functional surfaces of the blades that arise during mechanical processing lead to a decrease in the engine efficiency and an increase in fuel consumption. To ensure the accuracy of manufacturing the functional surfaces of the blades during the technological process, it is necessary to know the conditions under which cutting occurs. The work uses an approach based on the distribution of the entire range of cutting speeds into five speed oscillation zones. It was established that the third speed zone is the most unfavorable during milling of blades on multi-coordinate CNC machines. It is characterized by high-intensity vibrations, which worsens the quality of the machined surface and reduces the stability of the cutter. Their cause is regenerative oscillations, which are excited during machining by the trace left on the cutting surface by the accompanying free oscillation. The purpose of the study is to determine the influence of the axial depth of cut on the quality of the machined surface during milling in the third speed zone of vibrations. The results of the experiments showed that due to the peculiarities of up-milling with an axial depth of cut of ap = 1 mm, waviness on the machined surface is not formed, even in the presence of regenerative oscillations. The obtained data allow us to develop recommendations for the selection of cutting modes that minimize the amplitude of oscillations and ensure that the monowheel blades meet high operational requirements.