Effects of geometric angle and cutting speed on cutting forces and tool wear of ceramic cutting tools during peripheral up-milling of high-density fiberboard

In this paper, cutting forces and tool wear of ceramic cutting tools are investigated by up-milling high-density fiberboard under different geometric angles and cutting speeds. The results show that tangential force (F_t) and normal force (F_r) decrease with the increase of rake angle. The values of F_t and F_r at the higher speed cutting condition are lower than that at the lower speed condition. The flank wear (VB) declines with increased clearance angle and decreased cutting speed. The tool wear patterns observed on the ceramic cutting tools are pull-out of grain, cracking, tipping, and flanking. Abrasive wear and adhesive wear are the main mechanisms of the ceramic cutting tools. In all, on the premise of guaranteeing the ceramic cutting tools’ strength, the ceramic cutting tool with a bigger rake angle and clearance angle is advisable in high-density fiberboard machining, in terms of lowering the energy consumption and production cost required for machining.     

Comparative assessment of coated and uncoated ceramic tools on cutting force components and tool wear in hard turning of AISI H11 steel using Taguchi plan and RMS

This study investigated the cutting performance of coated CC6050 and uncoated CC650 mixed ceramics in hard turning of hardened steel. The cutting performance was mainly evaluated by cutting force components and tool wear. The planning of experiments was based on Taguchi’s L₃₆ orthogonal array. The response surface methodology and analysis of variance were used to check the validity of multiple linear regression models and to determine the significant parameter affecting the cutting force components. Tool wear progressions and, hence, tool life, different tool wear forms and wear mechanisms observed for tools coated with TiN and uncoated mixed ceramics are presented along with the images captured by digital and electron microscope. Experimental observations indicate higher tool life with uncoated ceramic tools, which shows encouraging potential of these tools to hard turning of AISI H11 (50 HRC). Finally, tool performance indices are based on units which characterise machined cutting force components and wear when hard turning.     

Investigation on tool wear process of milling wave-transmitting Si3N4 ceramics

Due to the low fracture toughness of wave-transmitting Si₃N₄ ceramics, the special material removal mechanism causes the tool wear to be different. The paper presents the tool wear forms and mechanism under different milling depth. The effect of tool wear on cutting force and machined surface morphology is discussed. Tests have been performed under typical conditions of cutting depth of 0.3 mm (in plastic-domain processing) and 0.4 mm (in brittle-domain processing). The results show that the abrasive wear caused by the chips is the main mechanism of the cutting edge wear and the flank wear, the increase of the side edge rear angle with tool wear is the main cause of the chipping phenomenon. The cutting depth is a significant influence parameter to the wear characteristics, and two types have been distinguished. As the material removal volume ascending, the cutting edge wear and the flank face wear has a stable period, and the root-mean-square deviation of processing surface increases to 1.6 μm, while that increase with the material removal volume continuously, and the processing surface decreases to 1.4 μm. It has been proved that the cutting force tends to increase first and then decrease as the material removal volume is about 4320 mm³.     

The study of the influence of wear of a cutting tool of cBN-based composite material on the tool fracture probability in the finish turning of hardened steels

The authors have experimentally clarified the influence of the tool wear on the tool fracture probability in the finish turning of hardened steels of various hardness values using a tool with a round cutting insert of cBN/Si₃N₄ composite. The maximum stresses and fracture probability have been determined for the tool face and flank. Recommendations regarding the use of cBN/Si₃N₄-inserted cutting tools are provided.     

Tool life and cutting forces when machining XC 45 steel

Machinability equations have been developed for prediction of tool life when machining XC 45 steel with P 10 and P 30 carbide inserts. A marked difference in cutability was observed between separate batches of P 10 inserts. A new criterion of tool life is suggested.

Equations are developed relating cutting forces to cutting conditions and to tool wear measurements. It is suggested that the percentage increase of the feed force may be suitable as a monitor of tool performance. The effect of cratering upon feed force is discussed and it is concluded that cratering should not necessarily affect feed force.

A slight positive correlation between cutting force and cutting speed has been observed for the radial and feed forces but not for the vertical cutting force.     

Effects of vegetable-based cutting fluids on the wear in drilling

This study focuses on both formulation of vegetable-based cutting fluids (VBCFs) and machining with these cutting fluids. For this purpose, characterizations of chemical and physical analyses of these formulated cutting fluids are carried out. In this study, performances of three VBCFs developed from crude sunflower oil, refined sunflower oil, refined canola oil and commercial semi-synthetic cutting fluid are compared in terms of tool wear, thrust force and surface roughness during drilling of AISI 304 austenitic stainless steel with HSSE tool. Experimental results show that canola-based cutting fluid gives the best performance due to its higher lubricant properties with respect to other cutting fluids at the constant cutting conditions (spindle speed of 750 rpm and feed rate of 0.1 mm/rev).     

Effect of cutting speed on the performance of Al2O3 based ceramic tools in turning nodular cast iron

This paper presents the results of an experimental investigation on the effect of cutting speed in turning nodular cast iron with alumina (Al₂O₃) based ceramic tools. Three different alumina based ceramic cutting tools were used, namely TiN coated Al₂O₃ + TiCN mixed ceramic, SiC whisker reinforced Al₂O₃ and uncoated Al₂O₃ + TiCN mixed ceramic tool. Turning experiments were carried out at four different cutting speeds, which were 300, 450, 600 and 750 m/min. Depth of cut and feed rate were kept constant at 1 mm and 0.1 mm/rev, respectively, throughout the experiments. Tool performance was evaluated with respect to tool wear, surface finish produced and cutting forces generated during turning. Uncoated Al₂O₃ + TiCN mixed ceramic was the worst performing tool with respect to tool wear and was the best with respect to surface finish. SiC whisker reinforced Al₂O₃ exhibited the worst performance with respect to cutting forces. If tool wear, surface finish and cutting force results are considered together, among the three tools studied, TiN coated Al₂O₃ + TiCN mixed ceramic tool is the most suitable one for turning nodular cast iron, especially at high cutting speeds (V_c > 600 m/min).     

An analytical tim6 domain evaluation of the cutting forces in BTA deep hole machining using the thin shear plane model

This paper presents an analytical approach to describe the cutting forces in 1ST A deep hole machining processes in the time domain. The method takes into account the effect of different machining conditions. Since the cutting velocities employed in BTA deep hole machining process are relatively high, and since small chips are produced due to the presence of tool chip breakers, the analysis is developed on the basis of the thin shear plane model.

The cutting velocity is a linear function of radius and the rake angle. Cutting is different in the two regions of the cutting tool, so the total cutting force acting on the cutting tool is determined by integrating the force on a small incremental thickness of the cutting tool. This approach, to predict the value of the cutting forces without resorting to any empirical techniques, clearly illustrates the effect of various system parameters on the machining process.

The resultant force system on a new BTA cutting tool consists of an axial force and torque. But with the increase in the number of holes bored, not only does the cutting profile deteriorate, but the wear pads do too. The resultant force system will then consist of three force components and a torque, due to the fact that the forces are not balanced at the wear pads. Under such conditions, the cutting force equations derived in the latter half of the paper, coupled with the properties of the randomly varying component, can be used as the forcing function on the machine tool to evaluate not only the response but also the regions of stability and instability during the machining.     

On the calculation of cutting forces and chip-tool contact interaction characteristics in cutting ductile metals

Based on a comparative analysis of experimental and calculated (by two different relations) cutting forces, the tangential stresses in the reference shear plane during chip formation has been found to be equal to the true ultimate stress of the workpiece material in mechanical tests. The author puts forward the methods for assessment of forces and stresses separately on the areas of plastic and elastic contact between the chip and the tool and some other chip formation characteristics from the measured chip reduction coefficient K _l . The angle of action of the cutting force is proposed to be determined as a sum of angles $\omega = \left( {\frac{\pi } {4} - \Phi } \right) + \Delta \omega$ , where Δω decreases with increasing tool rake at γ ≥ 0 but has almost no effect on the accuracy of assessment of the principal cutting force component P _z . The paper gives examples of cutting force determination in machining steel 10 and steel 08Kh18N10T using a tool with γ = 0 and 20°.     

Impact of graphite particle on milling of Al/15Al2O3 and Al/15Al2O3/5Gr composites

ABSTRACT

Hybrid Metal Matrix Composites (MMCs) are a new class of composites, formed by a combination of the metal matrix and more than one type of reinforcement having different properties. Machining of MMCs is a difficult task because of its heterogeneity and abrasive nature of reinforcement, which results in excessive tool wear and inferior surface finish. This paper investigates experimentally the addition of graphite (Gr) on cutting force, surface roughness and tool wear while milling Al/15Al₂O₃ and Al/15Al₂O₃/5Gr composites at different cutting conditions using tungsten carbide (WC) and polycrystalline diamond (PCD) insert. The result reveals that feed has a major contribution on cutting force and tool wear, whereas the machined surface roughness was found to be more sensitive to speed for both composite materials. The incorporation of graphite reduces the coefficient of friction between the tool–workpiece interfaces, thereby reducing the cutting force and tool wear for hybrid composites. The surface morphology and worn tool are analyzed using scanning electron microscope (SEM). The surface damage due to machining extends up to 200 µm for Al/15Al₂O₃/5Gr composites, which is beyond 250 µm for Al/15Al₂O₃ composites.     

Effect of hydrogen adsorption by 40Kh steel on the force parameters of cutting, stresses in a tool, and its wear resistance

We established that a decrease in the components of cutting forces owing to electrolytic hydrogen adsorption by blanks does not yet guarantee a positive effect of hydrogen treatment on the durability of cutting tools. The approach based on the determination of local force parameters of cutting, such as the tangential and normal stresses at the tool working surfaces, is more promising. We established the effect of hydrogen adsorption on the durability of cutting toolsK _{v 20} andK _{v 60}. The speedv ₂₀ orv ₆₀ that corresponds to a durability of 20 or 60 min, respectively, served as a durability index. The coefficient of the effect of hydrogen adsorption on the durability of the cutting tool (K _{v 20} andK _{v 60}) was calculated as the ratio between the values ofv ₂₀ orv ₆₀ for cutting of hydrogenated and original blanks. The durability of cutting tools of high-speed steel and hard alloy increases when using comparatively soft modes of hydrogen adsorption (the current density is less than 0.1 kA/m²). For harder modes, a negative effect of the treatment is already observed, despite a decrease in the components of cutting forces. Hydrogen-adsorption technologies have better prospects as applied to tools of hard alloys. Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 35, No. 6, pp. 95–100, November–December, 1999.     

Development of ANFIS model and machinability study on dry turning of cryo-treated PH stainless steel with various inserts

This present investigation deals about the machinability comparison of cryogenically treated 15-5 PH stainless steel with various cutting tools such as uncoated tungsten carbide, cryogenic-treated tungsten carbide and wiper geometry inserts. Cryo-treated PH stainless steel is considered as the work material in this investigation and experimental trials were performed under dry turning condition. The machinability aspects considered for evaluation are cutting force (F_z), surface roughness (R_a) and tool wear. The outcomes of experimentation reveal that the tungsten carbide inserts which are cryogenically treated provide improved performance in machining while comparing with conventional and wiper geometry inserts at all machining conditions. The measured cutting force and the observed flank wear were less for the cryo-treated inserts. However, wiper tool produces a better surface finish during machining. An artificial intelligence decision-making tool named Adaptive Neuro Fuzzy Inference System has been evolved to determine the relation among the considered input machining variables and output measures, namely cutting force and surface roughness of the machined surface. An analysis has been performed to compare the results obtained from developed models and experimental results.     

Studies on Machining Parameters While Milling Particle Reinforced Hybrid (Al6061/Al2O3/Gr) MMC

In this article, response surface methodology has been used for finding the optimal machining parameters values for cutting force, surface roughness, and tool wear while milling aluminum hybrid composites. In order to perform the experiment, various machining parameters such as feed, cutting speed, depth of cut, and weight (wt) fraction of alumina (Al₂O₃) were planned based on face-centered, central composite design. Stir casting method is used to fabricate the composites with various wt fractions (5%, 10%, and 15%) of Al₂O₃. The multiple regression analysis is used to develop mathematical models, and the models are tested using analysis of variance (ANOVA). Evaluation on the effects and interactions of the machining parameters on the cutting force, surface roughness, and tool wear was carried out using ANOVA. The developed models were used for multiple-response optimization by desirability function approach to determine the optimum machining parameters. The optimum machining parameters obtained from the experimental results showed that lower cutting force, surface roughness, and tool wear can be obtained by employing the combination of higher cutting speed, low feed, lower depth of cut, and higher wt fraction of alumina when face milling hybrid composites using polycrystalline diamond insert.     

刀具磨损声发射信号小波分析中小波基的选取

针对在用小波理论分析刀具磨损声发射（AE）信号时选取不同的小波基对分析结果有重要影响的问题,通过对小波基性质和刀具磨损AE信号特点的研究,从理论上分析了小波分析中刀具磨损AE信号处理中小波基选取的方法。在试验验证过程中,根据信号在小波包分解前后遵循能量守恒的原理,用四种小波基对刀具磨损AE信号进行三层小波包分解。以经小波包分解后AE信号各频带上的频带能量为特征参数,比较四种情况下特征参数的变化,验证了理论分析的正确性。     

Experimental Study on Hybrid Cryogenic and Plasma-Enhanced Turning of 17-4PH Stainless Steel

This article presents machinability of 17-4PH stainless steel using a hybrid technique composed of plasma-enhanced turning and cryogenic turning. First of all, using some primary experimental tests and nonlinear regression, a mathematical model was developed for surface temperature of uncut chip as a function of plasma current and cutting parameters. Then, the influence of cutting speed (V_c), feed (f), and surface temperature of uncut chip (T_sm) was studied on surface roughness (R_a), cutting force (F_z), and tool flank wear (V_B). The results show that hybrid turning (HYT) is able to lower the main cutting force and tool flank wear in comparison with conventional turning. In addition, surface roughness was improved except for high level of surface temperature of uncut chip. However, hardness measurement of machined workpiece showed that HYT does not change the hardness of machined surface.     

Characteristics of the wear process in the cutting of free-cutting steels

The paper brings some interesting results of the investigation of the cutting edge wear at cutting of free cutting steels by cemented carbide plates. These steels are characterized by the additions of sulphur and lead to increase machinability. The experimental results have shown that the additives of sulphur and lead can strongly affect not only chip generation but also the form and rate of wear. Previous investigations have indicated clearly that the criterion of wear on the clearance faces provides too little information on tool life. The experimental results have also shown that at equal wear on the clearance face the form and rate of wear on the rake face differ essentially.     

The effect of tool flank wear on the temperature distribution of a machined workpiece

Abstract

Temperature distributions in the chip, workpiece and tool during orthogonal machining were calculated numerically by the finite element method. The solution of the problem takes into account the thermal properties of the machined workpiece and the tool materials, which are the function of temperature. The effects of different flank wear under different cutting speeds on the temperature distributions of the machined workpiece were analyzed. It also provided an assumption for measuring the frictional force and the normal force on the flank face. The assumption was verified by experimental data.     

Experimental Investigation on Sialon Ceramic Inserts for Ultra-high-speed Milling of Inconel 718

A series of milling aerospace material Inconel 718 experiments were conducted with a sialon ceramic tool to investigate chip evolution, cutting force, and tool wear at different cutting speeds. Round inserts were used at ultra-high-speeds under dry cutting conditions. A scanning electron microscopy and an optical microscope were used to observe the worn surfaces and to reveal the wear mechanisms of the inserts. The experiment results showed that the macroscopic shape of the chips was small scraps and fan-shaped. With the increase in the cutting speed, the plastic deformation of the chips was increasingly serious. The minimal average cutting forces were obtained at v_c = 700 m/min. The rise of cutting temperature was resulted from the increase in cutting deformation work and friction work with cutting speed. The combined effect of thermal stress and mechanical stress contributed to the tool chipping, flaking, microcrack propagation, abrasion, and adhesion which were the primary reasons of the sialon ceramic tool wear.     

Cryogenic turning of the Ti–6Al–4V alloy with modified cutting tool inserts

Productivity in the machining of titanium alloys is adversely affected by rapid tool wear as a consequence of high cutting zone temperature. Conventional cutting fluids are ineffective in controlling the cutting temperature in the cutting zone. In this research work, an attempt has been made to investigate the effect of liquid nitrogen when it is applied to the rake surface, and the main and auxiliary flank surfaces through holes made in the cutting tool insert during the turning of the Ti–6Al–4V alloy. The cryogenic results of the cutting temperature, cutting forces, surface roughness and tool wear of the modified cutting tool insert have been compared with those of wet machining. It has been observed that in the cryogenic cooling method, the cutting temperature was reduced by 61–66% and the surface roughness was reduced to a maximum of 36% over wet machining. The cutting force was decreased by 35–42% and the flank wear was reduced by 27–39% in cryogenic cooling over that of wet machining. Cryogenic cooling enabled a substantial reduction in the geometry of tool wear through the control of the tool wear mechanisms. The application of liquid nitrogen to the heat generation zones through holes made in the cutting tool insert was considered to be more effective over conventional machining.     

AlN-(TiCr)B2 ion-plasma coating for cutting tools of cBN-based polycrystalline superhard material

The microstructure and oxidation kinetics of the surface layers of AlN-(TiCr)B₂ coating produced by magnetron RF sputtering have been studied in the course of the coating formation and use in tools of cBN-based polycrystalline superhard materials in machining ShKh 15 hardened steel. The coating is formed with the liquid phase present. After cutting the formation of two-layer tribofilm with a nanosized external layer has been revealed on the surface of the cutting insert. The tribofilm phase composition has been defined by a layer-by-layer Auger analysis. The film external nanosized layer is a glassy phase as solid solutions of Fe₂O₃-Al₂O₃ oxides that acts as a solid lubricant. As the cutting speed increases, the wear rate of a tool with a coating has been found to decrease as compared with tools without a coating.