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EN
The Inconel 718 alloys, which are primarily temperature resistant, are widely used in aviation, aerospace and nuclear industries. The study on dry cutting processes for this alloy becomes difficult due to its high hardness and low thermal conductivity, wherein, most of the heat transfers due to friction are accumulated over the tool surface. Further, several challenges like increased cutting force, developing high temperature and rapid tool wear are observed during its machining process. To overcome these, the coated tool inserts are used for machining the superalloys. In the present work, the cemented carbide tool is coated with chemical vapor deposition multi-layering Al 2O 3/TiCN under the dry cutting environment. The machining processes are carried out with varying cutting speeds: 65, 81, 95, and 106 m/min, feed rate 0.1 mm/rev, and depth of cut 0.2 mm. The variation in the cutting speeds can attain high temperatures, which may activate built-up-edge development which leads to extensive tool wear. In this context, the detailed chip morphology and its detailed analysis are carried out initially to understand the machining performance. Simultaneously, the surface roughness of the machined surface is studied for a clear understanding of the machining process. The potential tool wear mechanism in terms of abrasion, adhesion, tool chip off, delaminating of coating, flank wear, and crater wear is extensively identified during the processes. From the results, it is observed that the machining process at 81 m/min corresponds to a better machining process in terms of lesser cutting force, lower cutting temperature, better surface finish, and reduced tool wear than the other machining processes.
EN
Tool wear and surface roughness as performance indexes are considered to be the most important in terms of hardened materials’ machinability. The best combination of cutting parameters which enhances the compromise between tool life, productivity and machined surface quality contribute to benefice on production cost, which makes manufacturing industry interested in it. The aim of this research is to investigate the life of ceramic cutting tool and machining productivity together with surface roughness during turning of hardened steel C45, with focus on the selection of the optimal cutting parameter combination. The experiments are carried out based on uni-factorial planning methodology of cutting speeds and feed rates. The results show that the mixed ceramic tool is suitable for turning hardened steel C45 (40 HRC) and the conclusion is that it performed well in terms of tool life, productivity and surface quality at a combination of cutting speed (200 m/min), feed (0.08 mm/rev) and depth of cut (0.3 mm). Additionally, a tool life model has been proposed which is presented very high coefficient of determination.
3
Content available remote A review of the recent investigations regarding texturized cutting tools
EN
This paper presents some important, recently performed investigations on the laser texturing technology applied to the PCD and PCBN cutting tools and some resulting process outputs including cutting forces, tool wear indexes concerning both rake and flank tool faces. It was documented that the properly texturized tool faces results in a substantial reduction of cutting forces, elimination of the adhesion interaction between the tool and the chip, and reduction of abrasive and diffusion tool wear. The role of additional lubrication supply to the cutting zone with modified contact properties is discussed.
PL
W artykule przedstawiono kilka ważnych, niedawno przeprowadzonych badań nad technologią teksturowania laserowego zastosowaną w narzędziach skrawających z PCD i PCBN oraz niektóre wynikające z tego procesu wyniki odnośnie do siły skrawania, wskaźników zużycia narzędzia, dotyczące zarówno powierzchni natarcia, jak i powierzchni bocznej narzędzia. Udokumentowano, że odpowiednio teksturowane powierzchnie narzędzi powodują znaczne zmniejszenie sił skrawania, eliminację interakcji adhezyjnej między narzędziem a wiórem oraz zmniejszenie zużycia ściernego i dyfuzyjnego narzędzia. Omówiono rolę dodatkowego doprowadzania smaru do strefy skrawania o zmodyfikowanych właściwościach stykowych.
EN
In machining applications predominantly for automated machining cells, tool life is often not used to its full extend and cutting tools are exchanged prematurely to avoid tool breakage and thus machine downtime or even damage at work piece or machine. Both effective process monitoring and adequate process control require reliable data from sensors and derived indicators that enable meaningful evaluation. Acceleration measurement by the instrumented tool holder provides signals with high quality from close to the cutting zone. Using the monitoring system, the gained data of the instrumented tool holder can be analyzed especially for the use case of unexpected tool wear, chipping of the cutting edge or breakouts at end mills. This paper describes the data analysis based on the rotational sensor and the corresponding effects on the measurement, an advanced assessment of the spectral distribution in the frequency domain and the experimental results of a test series.
EN
This paper highlights tool wear mechanisms in the machining of heat resistance alloys including nickel-based Inconel 718 alloy which is one of the most popular material in the aircraft industry. Special attention was paid to the notch wear which develops on the flank face due to high temperature oxidation of the cutting tool material at temperature of about 800°C. The experimental procedure includes the diffusion couple methods and tool wear tests which assess the degradation of the deposited coating. The obtained results were supported by SEM images of the flank face periphery and EDS analysis performed in the regions of intensive oxidation. Some conclusions and ongoing research on the investigation of the oxidation phenomenon of cutting tool materials are outlined.
EN
Hard machining is a process that has become highly recommended for replacing grinding in the manufacturing industry. This is due to its ability to machine complex shapes with reduced production costs by reducing the machining time and being an ecological process. Three technological parameters determine the quality and productivity generated from this process: cutting vibration, surface roughness and tool wear. Therefore, the analysis of the correlation between them is very important. In the present investigation, the analysis of the correlation between cutting vibration, surface roughness and tool wear during a dry machining of hardened steel with a mixed ceramic tool is conducted in order to control these parameters online. This analysis is validated by developing predictive mathematical models. To neutralize the effect of cutting parameters, a combination of parameters such as cutting speed, feed rate and depth of cut to be used in the experimental tests is selected from the literature based on a quality-productivity optimum performance. In the early stage, the effect of machining time on the three technological parameters is studied, then assessed by developing predictive mathematical models. In the second stage, an experimental and statistical analyses such as the Pearson and Spearman correlation methods are employed to determine correlations between tool wear, surface roughness and cutting vibration. Each parameter is compared with the other two. The models and their validations are developed using the Minitab 16 tool, and the predictions are obtained with desirable deviations. The examination of the outcomes from the first stage reveals that the machining time has a significant effect on the three parameters. The regression models are found to be satisfactory in predicting each technological parameter. In the second stage, the results show a strong correlation between tool wear and cutting vibration, confirmed by the high Pearson and Spearman coefficients. The correlations between surface roughness and tool wear or the cutting vibration are strong only when the flank wear Vb is inferior 0.3 mm (which is required by the ISO standard). The regression models are developed with a desirable coefficient of regression (R2). The novelty of this work lies in the fact that we consider the cutting vibration as a response generated the during cutting process and not as a variable affecting the other technological parameters. This was rarely studied in previous researches.
EN
As an important research area of modern manufacturing, tool condition monitoring (TCM) has attracted much attention, especially artificial intelligence (AI)- based TCM method. However, the training samples obtained in practical experiments have the problem of sample missing and sample insufficiency. A numerical simulation- based TCM method is proposed to solve the above problem. First, a numerical model based on Johnson-Cook model is established, and the model parameters are optimized through orthogonal experiment technology, in which the KL divergence and cosine similarity are used as the evaluation indexes. Second, samples under various tool wear categories are obtained by the optimized numerical model above to provide missing samples not present in the practical experiments and expand sample size. The effectiveness of the proposed method is verified by its application in end milling TCM experiments. The results indicate the classification accuracies of four classifiers (SVM, RF, DT, and GRNN) can be improved significantly by the proposed TCM method.
EN
The present research employs the statistical tool of response surface methodology (RSM) to evaluate the machining characteristics of carbon nanotubes (CNTs) coated high-speed steel (HSS) tools. The methodology used for depositing carbon nanotubes was Plasma-Enhanced Chemical Vapor Deposition (PECVD). Cutting speed, thickness of cut, and feed rate were chosen as machining factors, and cutting forces, cutting tooltip temperature, tool wear, and surface roughness were included as machining responses. Three-level of cutting conditions were followed. The face-centered, Central Composite Design (CCD) was followed to conduct twenty number of experiments. The speed of cutting and rate of feed have been identified as the most influential variables over the responses considered, followed by the thickness of cut. The model reveals the optimized level of cutting parameters to achieve the required objectives. The confirmation experiments were also carried out to validate the acceptable degree of variations between the experimental results and the predicted one.
EN
The article describes how different friction coefficients under certain cutting conditions and parameters affect the formation of the stress-strain and thermal states of the product when titanium alloy machining. A new research methodology is used for the study. Firstly, in the initial data for simulation, each time a different declared coefficient of friction is proposed, and every such task of the cutting process modelling is solved for various cutting parameters. The second stage analyzes how these coefficients influence the stress-strain and thermodynamic state of the workpiece and tool during cutting, as well as the tool wear dynamics. In the third stage of the study, ways for ensuring these analytically-grounded tribological cutting conditions are proposed. The analysis of different wear criteria in the simulation models of titanium alloys cutting is carried out. Experimental studies confirm simulation results.
PL
Zaproponowano sposób obliczeniowego oszacowania wpływu zużycia narzędzi skrawających na intensywność zużywania korozyjnego warstwy wierzchniej materiału obrabianego. Cechą charakterystyczną podejścia jest ocena stopnia zużycia korozyjnego w zależności od zużycia narzędzia, parametrów chropowatości powierzchni przedmiotu obrabianego i stopnia utwardzania warstwy wierzchniej na zimno, a także parametrów warunków obróbki technologicznej (parametrów skrawania, geometrii narzędzia skrawającego, właściwości obrabianego materiału i narzędzia).
EN
A possible variant for calculated estimation of the degree of the impact of the cutting tool wear on the value of the part’s surface layer wear obtained during processing with the edge tool, due to atmospheric corrosion, is presented. The feature is the evaluation of the wear rate and its numerical value depending on the tool wear, roughness parameters of the work piece surface, and the degree of cold hardening of the surface layer, as well as parameters of the technological machining conditions (cutting conditions, geometry of the tool cutting part, properties of the machined and the tool materials).
EN
The paper presents the results of experimental determination of the Surface Geometrical Structure (SGS) parameters and tool wear during turning the polymer concrete. Until now, all literature reports have shown that the smoothness and roughness of the mineral cast surfacewas obtained directly from the mold. However, new applications of polymer concrete, even for some parts of the machine tools, forced the producers to carry out machining, which would improve the parameters of the surface layer. The topic of machining ceramic-based composite materials is a new chapter in the field of machining, which has not been sufficiently researched so far. The article describes the process of experimental determination of dependence of surface layer and tools wear parameters from cutting parameters during longitudinal turning of polymer concrete. The turning was carried out using plates made of a cubic boron nitride (CBN). After machining, the surface roughness and the maximum width of the flank wear were measured. On this basis, the mathematical model of the surface layer and tools wear parameters versus cutting parameters were defined. The authors also attempted to explain the phenomena occurring in the machining zone using variable cutting parameters. Microscopic pictures of CBN plates after machining were also performed. After the study, the final conclusions about the machining of mineral cast material were formulated.
EN
During of hypereutectic Al-Si alloys, tool wear increases owing to the presence of silicon particles. Therefore, polycrystalline diamond tools are typically used, but they are very expensive. The purpose of this study is to examine the tool wear characteristics during the end milling of hypereutectic Al-Si alloy (A390–T6) by using comparatively inexpensive diamond-like carbon coated cemented carbide tools. Al-Si alloy was end-milled by changing the cutting speed. Our results revealed that the width of flank wear land increased monotonously with increasing of the cutting force regardless of the cutting speed. In addition, the experimental equation of the width of flank wear land was derived as a function of cutting speed and time, and it was clarified that width of flank wear land could be approximated.
13
EN
Knowledge of the tool wear state in machining has become an important issue in research and industrial application. Current systems use the spindle power or cutting force as measured variable and refer it to a taught set point. However, this method lacks the ability to adapt to new work piece geometries. A new approach focusses on the tool instead of the work piece, and uses a sensory tool holder with integrated strain gauges. This tool holder provides polar figures whose shapes relate to the engagement conditions and whose area is a function of the tool load. As the tool load increases with tool wear, the area of the polar figures provides information about the tool wear status, and with knowledge about the engagement conditions, the model can be calibrated.
EN
The effect of the cutting fluid with zinc aspartate on the quality of the workpiece surface layer is reported. Until now, zinc aspartate has been used primarily in medicine and pharmacology. This paper compares the ecological cutting fluid containing zinc aspartate with a classic mineral oil-based coolant. Toxicity tests and a controlled process of tool wear during face turning were performed. Test results indicate that the use of zinc aspartate-based cutting fluids contributes to the reduction of the material roughness parameter values up to 35%, benefitting the final quality of the workpiece.
PL
W pracy przedstawiono wyniki badań wpływu cieczy chłodząco-smarującej z asparaginianem cynku na jakość technologiczną warstwy wierzchniej obrabianych elementów. Asparaginian cynku dotychczas nie był stosowany w takich rozwiązaniach, głównie wykorzystywany był w medycynie i farmakologii. W badaniach przeprowadzono analizę porównawczą proekologicznego chłodziwa zawierającego asparaginian cynku z klasycznym chłodziwem opartym na bazie oleju mineralnego. Ciecze chłodząco-smarujące poddano badaniom toksyczności oraz wykonano kontrolowany proces eksploatacji narzędzi w czasie toczenia poprzecznego. Wyniki badań wskazują, że zastosowanie chłodzenia cieczą na bazie asparaginianu cynku redukuje parametry chropowatości obrabianego materiału nawet o 35%, korzystnie wpływając na jakość finalną detalu.
EN
Additive Manufacturing (AM) technologies are increasingly applied in various industries since they provide the possibility to manufacture the components with high geometrical complexity easier and faster than traditional processes. However, the subsequent semi-finish/finish machining operations such as drilling, turning and/or milling are still necessary for AM parts to obtain the required surface textures and meet the practical requirements. As such, the AM parts usually indicate different machinability compared with conventionally produced ones in view of the different material microstructures. A comprehensive understanding of this machining effort is of great importance for similar engineering applications but not widely reported. Thus, an attempt was made in this work to address the effect of the material microstructure on the machining stability and tool wear behavior in dry drilling of the hard titanium alloys. The experimental results highlight a correlation between the tool wear behavior and material microstructures. A great number of micro-pits appeared on the tool flank face and the abrasive marks, coating delamination, as well as catastrophic failure of the cutting edge were found to be more obvious during machining the DMLS alloy. In contrast, adhesion wear followed by micro chipping and build-up edge were distinguished when machining the wrought Ti6Al4V. Meanwhile, heat treatment can improve the flow plasticity and reduce the brittleness of the AM material since catastrophic failure disappeared and chip adhesion becomes more predominant when machining the HTDMLS Ti6Al4V.
EN
The study presents the influence of the anti-wear coatings and the type of material from which the cutting tools are made of on the cutting temperature occurring on the tool. The cutting tools made of boron nitride and tungsten carbide composite were investigated. The methodology of measuring the cutting temperature using the thermoelement and thermovision techniques was presented. The results of the temperature measurements occurring on the cutting tool in the cutting zone were compared. The paper also presents a method of determining the effective emissivity of the tested tools, necessary for the correct temperature measurement using the non-contact method. The obtained data were interpreted and the relationships described, and then the results obtained were discussed.
PL
W artykule przedstawiono wyniki badań dotyczących wpływu obecności powłoki TiN na ostrzach mikrowierteł w procesie mikrowiercenia tworzywa kompozytowego na ich zużycie i trwałość, a także na jakość wykonywanych otworów. Do oceny zużycia i trwałości ostrza mikrowierteł posłużono się wskaźnikiem zużycia naroża ostrza, pomiarem osiowej siły skrawania oraz sumaryczną długością wiercenia. Jakość wykonywanych otworów oceniano natomiast na podstawie obrazów mikroskopowych krawędzi otworów od strony wejścia i wyjścia wiertła. Stwierdzono wyraźne różnice w efektach stosowania porównywanych narzędzi.
EN
In this paper the results of investigations concerning the influence of TiN coating on the edges of microdrills on their wear and durability, as well as on the quality of made holes in the process of microdrilling of composite material were presented. To evaluate the wear and durability of microdrills' edges, the index of edge corner wear, the measurement of axial cutting force and drilling length were used. The quality of drilled holes was evaluatedon the basis of microscopic images of the contour of holes on the entry and exit side of the drill. Significant differences were found in the effect of using the compared tools.
EN
The paper presents a new solution of asymmetrical mini disk tools for mining head of roadheader designed for hard and very hard rock mining. In the first part the benefits of disk tools used in TBM's and special tunneling machines were presented. Next part presents the results of works and laboratory tests performed for developing of new solution of asymmetrical mini disk tools. On the basis of these results new mining head equipped with mini disk tools with a complex trajectory was designed. The results of field tests with different constructional and material solutions of asymmetrical mini disk tools were presented. The directions for further development were described.
19
Content available remote Optimization of Inconel 718 milling strategies
EN
This paper applies to the tests of the machining of a part made of supper alloy – nickel alloy – Inconel 718, using a monolithic carbide cutter. The paper includes a different versions of cutting methods with variable cutting parameters and machining strategies. The used sustainable machining process allowed to obtain control over the tool wear.
PL
Artykuł dotyczy badań obróbki ubytkowej części wykonanej ze stopu na osnowie z niklu – Inconel 718, z zastosowaniem monolitycznego frezu z węglików spiekanych. Przedstawiono różne metody obróbki części przy zmiennych parametrach skrawania oraz strategiach. Zastosowano zrównoważony proces obróbki, który pozwolił uzyskać kontrolę nad zużyciem narzędzi skrawających.
EN
This paper highlights the performance of precision hard turning with CBN cutting tools from energy point-of-view with additional tool wear effect. For this purpose several wear tests were performed during which the tool nose wear VBC and the corresponding changes of component forces Fc, Ff and Fp were continuously measured. Based on the measured forces and geometrical characteristic of the uncut layer, specific cutting and ploughing energy were determined for several combinations of cutting parameters. Consequently, changes of energy consumption resulting from tool wear evolution for variable feed rate, depth of cut and tool nose radius were presented.
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