Effect Of Tool Nose Radius Research Articles

Effects of magnetic intensity on the machining quality and tool damage in nickel-based superalloys subjected to magnetic-assisted cutting

Nickel-based superalloys are widely used in engine components due to their excellent high-temperature strength. However, their low plasticity and low thermal conductivity pose significant challenges in machining, leading to poor quality of machined parts and severe tool wear. Magnetic-assisted machining has received considerable attention as a clean and effective machining method, but its application to nickel-based superalloys is rarely reported, necessitating further exploration of its potential. This study focuses on GH4169 alloy and explores the effects of magnetic-assisted cutting (MAC) with varying intensities on the machining quality and tool wear. The experimental results indicate that the introduction of a magnetic field improves the machining quality by reducing tool wear and built-up edge adhesion. Additionally, both the plasticity and thermal conductivity of GH4169 alloy are improved under the effect of magnetic field, resulting in an 11.4 % decrease in cutting temperature. However, when the magnetic intensity ranges from 0.03 T to 0.12 T, secondary serration of the chip edges manifests, resulting in notch wear on the tool nose and a deterioration of surface quality. This secondary serration is attributed to the combined effect of tool nose radius and material plasticity under the magnetic field. As the magnetic field intensity increases further, the secondary serration gradually diminishes, and the surface roughness can be reduced by 26.5 % compared to traditional cutting. This study analyzed the relationship between machined surface, tool wear, chip morphology and magnetic field, and revealed the reasons for the differences in machining quality at different magnetic field intensities. These findings provide more possibilities for future applications of magnetic-assisted cutting to improve the machining quality of nickel-based superalloys and other difficult-to-machine metals.

Abrasive water jet tool passivation: from mechanism to application

The passivation process of a tool is a necessary step in the manufacturing process, which could improve tool life and machining efficiency by removing microscopic defects of in tool surface (such as burrs and micro cracks) after grinding or polishing. The abrasive water jet passivation (AWJP) is one of the most commonly used processes for carbide, ceramic and steel materials tools. Nevertheless, the complex action law from passivation to machining performance is indistinct, which makes passivation parameters rely on empirical summaries. To fill this gap, this paper concentrates on the detailed review of AWJP and comprehensive assessment between machining performance and AWJP parameters. Firstly, the mechanism of AWJP is analyzed, and the influence law of jet parameters on the tool nose radius is investigated. Secondly, the effect of tool nose radius on the force in turning and milling are summarized and analyzed. The jet pressure, abrasive concentration and jet time are positively correlated with the tool nose radius. Additionally, then the tool nose radius is positively and negatively correlated with cutting force and tool wear, respectively. Finally, future directions regarding the different parameters in AWJP and the machine tool for tool passivation are proposed: to reveal the complex nonlinear relationships between the parameters in AWJP. Develop economical, practical and efficient tool passivation machine tools to improve passivation efficiency and passivation accuracy and apply them to domestic tool passivation technology.

Ultra-Precision Cutting and Characterization of Reflective Convex Spherical Blazed Grating Elements.

In this work, based on the diffraction principle of reflective blazed grating, the structure size of the convex spherical blazed grating unit is determined, the machining accuracy of the convex spherical blazed grating is formulated, the effects of tool nose radius and Poisson burr on the diffraction efficiency of the convex spherical blazed grating are analyzed, and the performances of cutting convex gratings with microcrystalline aluminum RSA6061 and RSA6061+ chemically plated NiP for two workpiece materials are compared. A convex spherical blazed grating with a radius of curvature R = 41.104 mm, substrate diameter 14 mm, grating density 53.97 line/mm, and blaze angle of roughly 3.8° is turned by a four-axis ultra-precision machining system by adjustment of the cutting tool, workpiece material, and cutting parameters, as well as modification of the layouts of the blazed grating on the convex sphere. The results of the testing of convex spherical blazed grating elements in both layouts show that the size error of the grating period is close for both layouts, the size error of grating height is smaller in the equal-along-arc layout, the blaze angle error in the equal-along-projection layout is only 0.74%, and the average roughness of the blazed surface is less than 5 nm to meet the processing quality requirements of the reflective convex spherical blazed grating. The greater the blaze angle accuracy of the blazed grating, the higher its diffraction efficiency, so the grating element with an equal-along-projection layout has a higher diffraction efficiency than the grating element with an equal-along-arc layout. RSA6061+ chemically plated NiP material is superior to RSA6061 material in Poisson burr height and blazed surface roughness, which is more suitable for Offner-type imaging spectrometers in the spectral range 0.95–2.5 μm (SWIR).

A Numerical Model for Predicting the Effect of Tool Nose Radius on Machining Process Performance during Orthogonal Cutting of AISI 1045 Steel.

This paper presents the development of a numerical model for predicting and studying the effects of tool nose geometries and its interactions with cutting parameters during orthogonal cutting of AISI 1045 steel. The process performance characteristics studied were cutting temperature, effective stress, cutting forces and tool wear. The cutting simulations were done using the commercial DEFORM-2D R V 11.3 software, based on the finite element method (FEM). The cutting tool used had a round nose with various nose radii (0.01–0.9 mm), while the machining parameters tested were the feed rate (0.1–0.3 mm/rev), the cutting speed (100–500 m/min) and the rake angle (–5° to +10°). The interactions between the tool nose radius and the cutting parameters (speed, feed) were found to affect mostly the cutting stress and, slightly, the tool wear rate. These interactions did not much influence the cutting temperature, that was found to be high when the tool nose radius and/or the cutting speed were high. The maximum temperature was found to occur at the middle of the tool-chip contact length and at the interaction of nose radius and flank face of the tool. Except for some fluctuations, there was no significant difference in tool wear rate between small and large nose radius scales.

Mapping ductile-to-fragile transition and the effect of tool nose radius in diamond turning of single-crystal silicon

Although it has long been known that tools with more negative rake angles allow the ductile regime when machining monocrystalline silicon, little has been discussed about the tool-material interaction. The microgeometric contact of the tool tip at this interface plays an essential role in the material remotion (ductile or brittle). In this paper, the tool rake angle was varied in order to change the value of the undeformed chip thickness once the tool cutting radius, formed in front of the tool rake face, changes when the tool rake angle becomes more negative. Based on the statistical design of the experiment applied to cutting tests, a map is built to relate the values of transition pressure in different crystallographic directions. This map assisted in determining the machining conditions with a ductile response into a broader spectrum based on the variation of the tool rake angle. The results obtained allowed to answer questions under which machining conditions and tool geometry account for better surface finishes, lower machining forces, and lower residual stresses. The response surfaces, from statistical design, provided answers capable of establishing under which cutting radii yielded more ductile material removal and avoided a brittle response related to the anisotropic behavior of the material. Finally, the brittle-to-ductile transition mapping determined a more suitable machining condition to diamond turn Fresnel lenses in single crystal silicon.

Study on effects of tool nose radius on the formation mechanism of edge defects during milling SiCp/Al composites

Silicon carbide particulate reinforced aluminum matrix composites (SiCp/Al) have received considerable attention in many engineering applications. However, the existence of dispersing SiC particles leads to particularly vulnerable edge quality of SiCp/Al composites in machining. It is very significant to improve the edge defects of SiCp/Al composites by optimizing the tool geometry. Cutting tool nose radius mainly determines the machining performance. Therefore, the effects of tool nose radius on the chip topography, cutting force, and edge geometry in face and dry milling of 20% SiCp/Al composites were investigated in the current work. Experiments were conducted with tool nose radius of 0.5, 1, 1.5, and 2 mm. The results showed that the shorter and wider chips were found with the increment in tool nose radius. It was also observed that the cutting force increased with the increment in tool nose radius. Based on the material removal mechanism with different tool nose radius, the feature maps of edge defects in SiCp/Al composites were established and studied. It was found that the outer and inner edge quality of the materials was improved with the increase of tool nose radius.

Tool nose radius effects in turning process

The main goal of this article is to study the effects of tool nose radius on some performances in turning process. An analytical approach is developed and adapted for cutting with round inserts or when only the round edge was engaged in the metal. The uncut chip area is evaluated as function to tool nose radius and discretized into some elements which are defined by their average uncut chip thickness and elementary edge direction angle. Cutting edge radius is considered and minimum uncut chip thickness is evaluated for each element. Hence, two mechanisms are studied in relation to the minimum uncut chip thickness: cutting and plowing. Effects of tool nose and cutting edge radii on cutting force components, tool/chip interface temperature, specific cutting energy, tool/chip contact length and chip thickness are investigated. Good agreement was found between experiments and predictive cutting forces when turning stainless steel.

Effect of tool nose radius in turning of novel Mg alloy

Machining parameters play a significant role in controlling the response variables such as cutting force, temperature, surface roughness, chip shape, etc. Therefore, a judicious selection of machining parameters becomes vital. Many studies have been done to analyze the effect of turning parameters on the response variables in the past. However, the literature on the influence of nose radius has been scanty. In this study, the effect of the nose radius of carbide inserts on the cutting force, cutting temperature, and surface roughness has been analyzed. A novel AM (Mg-7 wt%Al-0.9 wt%Mn) series Mg alloy developed using stir casting has been selected for the turning operation. The results showed that the nose radius has a strong influence on the cutting force and surface roughness. The cutting force is proportional to the nose radius, whereas the surface roughness is inversely proportional to the nose radius. The effect on temperature was lesser compared to the cutting force and surface roughness. Furthermore, the SEM images corroborate the obtained results.

Development of specific cutting energy map for sustainable turning: a study of Al 6061 T6 from conventional to high cutting speeds

This study presents the development of a novel Specific Cutting Energy (SCE) based process map for turning of Al 6061 T6 alloy from conventional to high-speed machining range. The newly developed SCE map for turning process was compared with already published SCE maps for orthogonal machining. The comparison of maps revealed that SCE consumption trends observed in turning process are similar to those observed in orthogonal machining. Low values of SCE were observed at high cutting speeds and high feed rates that demonstrate the benefit of high-speed machining. Similar to the orthogonal machining SCE map, a high energy consumption zone named as “avoidance zone” was observed at high cutting speeds and low feed rates. Surface roughness analysis performed in the avoidance zone established the presence of built-up-edge on cutting inserts that not only resulted in high energy consumption but also deteriorated the surface finish of the machined part. Furthermore, statistical analysis of experimental data also revealed the significant effect of tool nose radius on SCE consumption in high-speed machining range. This significance of tool nose radius for SCE consumption has not been reported earlier in literature.

Effect of tool nose radius and tool wear on residual stresses distribution while turning in situ TiB2/7050 Al metal matrix composites

In situ TiB2/7050 Al matrix composite is a new kind of particle reinforced metal matrix composite. With in situ synthesis method, a better adhesion at interfaces is achieved and hence improves mechanical properties. However, due to the presence of hard TiB2 ceramic particles, the tool wear problem is severer while machining TiB2/7050 Al composites compared with traditional metallic alloy. In order to have a deeper understanding of the residuals stress distribution during machining metal matrix composites, this paper investigates the effect of tool nose radius and tool wear on the residual stress distribution during turning TiB2/7050 Al composites. Four CBN tools with different tool nose radius (0.4, 0.6, 0.8, and 1.0 mm) are used. The cutting force and residual stress distribution beneath the machined surface have been analyzed when the CBN tools are new or worn (0.26 mm VB). The results show that the residual compressive stress distribution is always obtained on the machined surface and subsurface no matter the tools are new or worn. The larger tool nose radius causes the increase of cutting force, lower surface residual compressive stress, and deeper residual stress penetration layer. As the tool wear, the location of maximum residual compressive stress transfers from the machined surface to the deeper subsurface. Compared with the tool nose radius, the tool wear has more significant influence on the cutting force and residual stress distribution.

Mechanistic modelling for predicting cutting forces in machining considering effect of tool nose radius on chip formation and tool wear land

Tool wear during machining has been seen to result in changes in tool geometry, which adversely affect the performance characteristic of the process. Various force models have been proposed to compensate for the tool wear and thus enhance the process performance. The study undertaken proposes a mechanistic model to predict the cutting forces based on three-dimensional cutting operations. The model has been developed for predicting forces due to chip formation and due to worn-out cutting tool including cutting tool nose radius. The force that has been predicted due to chip formation is a function of chip flow angle and equivalent cutting edge geometry. The prediction of force due to worn-out cutting tool is based on the actual chip-tool contact area and the rubbing force. The total force estimated has been further optimised to get accuracy in the model. Optimisation process is achieved by using a technique of order preference by similarity to the ideal solution. Results of the proposed force model have been experimentally validated as well as found to be in good agreement with the results of the force models proposed by Huang and Liang [39] and Chinchanikar and Choudhury [21]. Further, a regression equation has been developed in order to check the adequacy of the proposed model. The modelling approach proposed may be readily extended to other machining operations such as drilling and milling.

Thermomechanical modeling of oblique turning in relation to tool-nose radius

ABSTRACTThis article aims at predicting machining performances for oblique turning in relation to tool-nose radius. A new geometric analysis for the uncut chip area is proposed as function of depth of cut, feed rate, tool-nose radius, and edge direction angle. Cutting edge is discretized into increments and average uncut chip thickness, elementary direction angle and elementary depth of cut are determined for each one. A new thermomechanical model is developed for each increment which is supposed to be an oblique machining with single cutting edge. The predicted cutting force components are in good agreement with experimental data over a wide range of cutting conditions. In particular, the effect of tool-nose radius and cutting parameters on chip geometry, cutting temperature, and cutting force components are studied. It is underlined that tool-nose radius promotes the increase in radial force, however, its influence on the other parameters is negligible.

Cutting mode analysis in high speed finish turning of AlMgSi alloy using edge chamfered PCD tools

Machining of aluminium alloys to high quality surface finish is seen as a challenge in dry turning using HSS and coated cemented carbide tools at conventional cutting speeds. The recent technological advancements have led to cutting edge preparation techniques like edge chamfering to provide higher load resistance and strength enhancement to the cutting edge of the inserts. These technologies have led to variation in cutting mode mechanism at lower feed rates and depth of cuts. This paper makes an attempt to develop a finite element model and experimental investigations of the effect of cutting edge chamfer on the cutting modes at low feed rates (0.005–0.125mm/rev) in high speed turning of AlMgSi (Al 6061 T6) alloy using polycrystalline diamond (PCD) tools. In the present work, the cutting modes are established based on the machining forces, surface roughness and chip morphology at varying cutting edge chamfer widths. Both the shearing and ploughing modes of cutting are observed during turning at low feed rates using edge chamfered tools. It is inferred from the present work that shearing mode of cutting dominates when surface roughness reduces with the reduction in feed rate and ploughing mode dominates when surface roughness increases with the reduction in feed rate. The minimum feed rate in the shearing dominated region is found to yield the best surface finish for different edge chamfer widths. The effect of tool nose radius at a constant edge chamfer width and chamfer angle on surface finish is analysed during the shearing and ploughing dominated modes of cutting. It is found that surface finish improves with the increase in tool nose radius during shearing mode of cutting and surface finish deteriorates at higher value of nose radius during ploughing mode of cutting. The outer surface of chip obtained by shearing mode at higher edge chamfer width is observed to have a distinct and uniformly spaced lamellar structure with the lamellae oriented perpendicular to the direction of chip flow. Whereas, the outer surface of the chip formed during ploughing mode has non-uniform randomly oriented lamellar structure. The present work suggests the minimum feed rate to be used in finish turning using edge chamfered PCD tools.

The effect of tool nose radius on surface integrity and residual stresses when turning Inconel 718™

This paper investigates the influence of tool nose radius on the residual stress distribution developed in Inconel 718 by finish turning. Although previous studies have shown that changes in rake angle, cutting edge geometry and nose radius can affect the tool performance and resulting workpiece surface integrity, no systematic study examining nose radius has been performed. Cutting force, microstructural alteration and residual stress distribution have been analysed for machining trials examining 2, 3, 4 and 6mm radius tools at various feed rates and in both the new and worn tool condition. In general the results show that an increase in tool nose radius results in; increased radial cutting forces, increased microstructural deformation depth, higher near surface tensile stresses (up to 1550MPa with a worn tool), and deeper tensile and compressive residual stress distribution.

Predictive modeling of surface roughness in lenses precision turning using regression and support vector machines

Slow tool servo (STS) turning is superior in machining precision and in complicated surface. However, STS turning is a complex process in which many variables can affect the desired results. This paper focuses on surface roughness prediction in lenses STS turning. An exponential model, based on the five main cutting parameters including tool nose radius, feed rate, depth of cut, C-axis speed, and discretization angle, for surface roughness prediction of lenses is developed by means of orthogonal experiment regression analysis. Meanwhile, a prediction model of surface roughness based on least squares support vector machines (LS-SVM) with radial basis function is constructed. Orthogonal experiment swatches are studied, and chaotic particle swarm optimization and leave-one-out cross-validation are applied to determine the model parameters. The comparison of LS-SVM model and exponential model is also carried out. Predictive LS-SVM model is found to be capable of better predictions for surface roughness and has absolute fraction of variance R 2 of 0.99887, the mean absolute percent error e M of 8.96 %, and the root mean square error e R of 10.68 %. The experimental results and prediction of LS-SVM model show that effects of tool nose radius and feed rate are more significant than that of depth of cut on surface roughness of lenses turning.

Prediction Model of Surface Roughness in Lenses Precision Turning

Due to the difficulties of processing lenses with complex surface,slow tool servo is applied in the turning of lenses.An exponential model,based on the five main cutting parameters including tool nose radius,feed,depth of cut,spindle speed and discrimination angle,for surface roughness prediction of lenses is developed by means of orthogonal experiment regression analysis.Meanwhile,a prediction model of surface roughness based on least squares support vector machine(LS-SVM) with radial basis function(RBF) is constructed.And orthogonal experiment swatches are studied,crossed grid search and leave-one-out cross-validation(LOO-CV) is applied to determine the model parameters.The comparison of LS-SVM model and exponential model is also carried out.Predictive LS-SVM model is found to be capable of better predictions for surface roughness and has correlation coefficient R2of 0.998 85,the root mean square error of 10.95%,and the mean absolute percent error of 9.28%.The experimental results and prediction of LS-SVM model show that effects of tool nose radius and feed are more significant than that of depth of cut on surface roughness of lenses turning.

Predicting the Effects of Cutting Parameters and Tool Geometry on Hard Turning Process Using Finite Element Method

To explore the effects of cutting speed, feed rate and rake angle on chip morphology transition, a thermomechanical coupled orthogonal (2-D) finite element (FE) model is developed, and to determine the effects of tool nose radius and lead angle on hard turning process, an oblique (3-D) FE model is further proposed. Three one-factor simulations are conducted to determine the evolution of chip morphology with feed rate, rake angle, and cutting speed, respectively. The chip morphology evolution from continuous to saw-tooth chip is described by means of the variations of chip dimensional values, saw-tooth chip segmental degree and frequency. The results suggest that chip morphology transits from continuous to saw-tooth chip with increasing feed rate and cutting speed, and changing a tool’s positive rake angle to negative rake angle. There exists a critical cutting speed at which the chip morphology transfers from continuous to saw-tooth chip. The saw-tooth chip segmental frequency decreases as the feed rate and the tool negative rake angle value increases; however, it increases almost linearly with the cutting speed. The larger negative rake angle, the larger feed rate and higher cutting speed dominate saw-tooth chip morphology while positive rake angle, small feed rate and low cutting speed combine to determine continuous chip morphology. The 3-D FE model considers tool nose radii of 0.4 mm and 0.8 mm, respectively, with tool lead angels of 0 deg and 7 deg. The model successfully simulates 3-D saw-tooth chip morphology generated by periodic adiabatic shear and demonstrates the continuous and saw-tooth chip morphology, chip characteristic line and the material flow direction between chip-tool interfaces. The predicted chip morphology, cutting temperature, plastic strain distribution, and cutting forces agree well with the experimental data. The oblique cutting process simulation reveals that a bigger lead angle results in a severer chip deformation, the maximum temperature on the chip-tool interface reaches 1289 deg, close to the measured average temperature of 1100 deg; the predicted average tangential force is 150N, with 7% difference from the experimental data. When the cutting tool nose radius increases to 0.8 mm, the chip’s temperature and strain becomes relatively higher, and average tangential force increases 10N. This paper also discusses reasons for discrepancies between the experimental measured cutting force and that predicted by finite element simulation.

Effect of Tool Nose Radius on Nano-Machining Process by Molecular Dynamics Simulation

Today, there is a need to understand the micro mechanism of material removal to achieve a better roughness in ultra precision machining (UPM). The conventional finite element method becomes impossible to use because the target region and grids are very tiny. In addition, FEM cannot consider the micro property of the material such as atomic defect and dislocation. As an alternative, molecular dynamics (MD) simulation is significantly implemented in the field of nano-machining and nano-tribological problems to investigate deformation mechanism like work hardening, stick-slip phenomenon, frictional resistance and surface roughness [1]. One of the machining parameters than can affect nano-cutting deformation and the machined surface quality is tool nose radius [2]. In this paper molecular dynamics simulations of the nano-metric cutting on single-crystal copper were performed with the embedded atom method (EAM). To investigate the effect of tool nose radius, a comparison was done between a sharp tool with no edge radius and tools with a variety of edge radii. Tool forces, coefficient of friction, specific energy and nature of material removal with distribution of dislocations were simulated. Results show that in the nano-machining process, the tool nose radius cannot be ignored compared with the depth of cut and the edge of tool can change micro mechanism of chip formation. It appears that a large edge radius (relative to the depth of cut) of the tool used in nano-metric cutting, provides a high hydrostatic pressure. Thus, the trust force and frictional force of the tool is raised. In addition, increasing the tool edge radius and the density of generated dislocation in work-piece is scaled up that is comparable with TEM photographs [6].

A study on the effect of tool nose radius in ultrasonic elliptical vibration cutting of tungsten carbide

Nowadays, ultrasonic elliptical vibration cutting (UEVC) technique is being successfully applied for ultraprecision machining of difficult-to-cut materials. Previous study reported that the tool geometry especially tool nose radius notably influences the performance of 1D ultrasonic vibration cutting (UVC). However, the effect of tool nose radius in the UEVC technique is yet to be studied. This study aims to investigate the effects of tool nose radius on the UEVC performance in terms of cutting force, tool wear and surface finish when machining a hard-to-cut material, sintered tungsten carbide (WC), using PCD tools. The experimental results show that the UEVC technique performs remarkably better in all aspects at a 0.6 mm nose radius compared to a lower (e.g. 0.2 or 0.4 mm) and a higher nose radius (e.g. 0.8 mm). When machining about 412 mm 2 surface area, an average surface roughness, R a of 0.010 μm is achieved with a 0.6 mm nose radius. Analyses are conducted to justify the findings in this study.

Studying The Effect of Tool Nose Radius on Workpiece Run Out and Surface Finish

Studying The Effect of Tool Nose Radius on Workpiece Run Out and Surface Finish