Higher Depth Of Cut Research Articles

Investigations on the machinability performance of Al2O3/TiCN CVD coated carbide tools in sustainable high-speed hard-turning of AISI 4340 alloy steel

Abstract This study investigates the effectiveness of CVD coated carbide inserts in turning hardened AISI 4340 steel at high-machining speed V=300,350m/min under sustainable dry cutting environment. Experiments were executed in accordance to Taguchi L4 orthogonal array and crucial machinability aspects tool life, tool wear progression and mechanism, cutting force, and surface roughness were evaluated in detail. The results of this study revealed that Al2O3/TiCN coating successfully inhibited the faster progression of tool wear at low cutting speed (300m/min), feed rate (0.05mm/rev) and depth of cut (0.1mm), thus delivering the highest tool life of 19.25 min and lowest cutting force of 76.8 N. However, better surface finish of 0.305µm was obtained at high cutting speed (350m/min), low feed rate (0.05mm/rev), and high depth of cut (0.1mm). Nevertheless, at high cutting speed (350 m/min) and feed rate (0.1 mm/rev), involvement of intense thermal-mechanical effects suppressed the effectiveness of coating and tool completed its useful life at 9.24 min. Severe flaking on the cutting edge was observed at high machining parameters. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis revealed that adhesion, oxidation, and small scale chipping and abrasion were the primary wear mechanisms attributing in competing the tool life criteria (Vb=300µm) in all cutting conditions. Furthermore, it was established that the cutting force and surface roughness increased with increasing tool flank wear due to coating delamination, material adhesion and tool chipping. This research emphasizes the significant potential of adopting Al2O3/TiCN coated carbide inserts for high-speed industrial hard-turning of AISI 4340 steel.

Experimental studies on reflective finishing of aluminum sheet by CNC abrasive lapping

ABSTRACT This study focuses on improving the surface properties of Aluminum (Al) sheets for imaging and optical applications. To achieve high efficiency and low damage, novel CNC abrasive lapping (CNC AL) techniques were proposed and tested. The experiments investigated the impact of various parameters, such as spindle speed, feed rate, and depth of cut, using two types of abrasives (PCD and hybrid PCD with Al2O3) on the surface quality (Ra) and reflectance (R) of the Al sheets. Optimal parameters were determined using Taguchi L9 and (S/N) analysis, favoring low spindle speed, low feed rate, and high depth of cut. Surface roughness was measured with Surfcom1400G, while SEM EDX, AFM, and 3D profilometer were used to assess surface microstructures. Significant improvement of 35-96% was observed in the highly reflective Al sheets using UV-VIS spectrophotometry and texture analysis in MATLAB.

Investigation of the effects of MQL and material hardness on energy consumption, vibration, and surface roughness in hard turning of AISI 52100 steel for a sustainable manufacturing

Turning hardened steels is more advantageous than cylindrical grinding. However, the machinability of hardened steel is difficult. Therefore, in this experimental study, two different AISI52100 steels with 45 and 50 HRC were machined with varying cutting parameters (feed rate: 0.15, 0.25, 0.35 mm/rev; cutting speed: 140, 155, 170 m/minute; depth of cut: 0.08, 0.12, 0.16 mm) under three different cooling conditions (dry, coolant, and MQL). According to the experimental result the lowest surface roughness, vibration, and energy consumption were obtained in cutting with MQL. With increasing feed rate and depth of cut, vibration, power consumption, and surface roughness increased, while energy consumption decreased because the machining time was shortened. With increasing cutting speed, surface roughness, tool vibration, and energy consumption decreased, while instantaneous power consumption and chuck vibration increased. For the lowest energy consumption, surface roughness, vibration, and highest machine tool performance for the ideal cutting condition, high hardness (50 HRC) using MQL, high cutting speed (145 m/minute), low feed rate (0.1 mm/rev), and high depth of cut (0.3 mm) should be preferred. Thus, 3.88% energy consumption, 58.25% surface roughness value, 10.06% chuck vibration value, and 28.80% tool vibration have decreased according to the average cutting conditions.

Self-Propelled Rotary Tools in Hard Turning: Analysis and Optimization via Finite Element Models.

This study investigates self-propelled rotary tool (SPRT) performance in hard turning using 3D finite element (FE) models. The FE models developed in this study are based on coupled temperature-displacement analysis using an explicit time-integration scheme. The developed FE models can predict chip morphology, cutting forces, tool and workpiece stresses and temperatures. For model verification, hard turning experiments were conducted using an SPRT on AISI 4340 bars. Cutting forces and maximum tool-chip interface temperatures were recorded and compared with the model findings. The effects of different process parameters were analyzed and discussed using the developed FE models. The FE models were run with a central composite design (CCD-25) matrix with four input variables, i.e., the cutting speed, the feed rate, the depth of the cut and the inclination angle. Response surfaces based on the Gaussian process were generated for each performance variable in order to predict design points not available in the original design of the experiment matrix. An optimization study was carried out to minimize tool stress and temperature while setting limits for the material removal rate (MRR) and specific cutting energy for the process. Optimized processes were found with moderate cutting speeds and feed rates and high depths of cut and inclination angles.

Process limits in high-performance peel grinding of hardened steel components with coarse CBN grinding wheels

Recent developments in the production processes for cubic boron nitride (CBN) abrasive grains have led to commercially available grain sizes larger than lg > 300 µm. These superabrasive grains allow higher material removal rates during grinding of hardened steel components. Currently, these components are pre-machined by turning processes before being hardened and eventually finished by grinding. However, the turning process can be substituted by grinding with coarse CBN-grains since higher depths of cut are achievable when machining hardened components. This paper investigates the process behaviour of vitrified and electroplated grinding wheels with large grain sizes during the machining of hardened steel components. Process forces, wear behaviour and workpiece surface roughness are investigated for three different grain sizes, and the process limits of both bond types are examined. The investigations show that vitrified tools do not fully suit the demands for peel grinding process with high material removal rates since wear by bond breakage occurs. The electroplated tools on the other hand are capable of very high material removal rates. Their wear behaviour is characterized by clogging of the chip space if the process limit is reached. Even so, both tools outperform a standard hard-turning process in terms of process time by 74% and 94% respectively. This process time reduction in combination with the possibility to use the same (machine) tool to machine both soft and hard sections of a workpiece adds flexibility to current process chains.

The Promise of Turning Induced Deformation Process for Synthesizing Magnesium Based Materials with Superior Mechanical Response

In recent times, an alternative synthesis pathway involving severe plastic deformation for Mg-based materials has been explored involving the generation of turnings according to a set of machining parameters and cold compaction into billets followed by hot extrusion. This is known as the turning induced deformation (TID) method and has shown potential to alter the properties of resulting Mg-based materials for the better, not to mention economic benefits arising from this processing method. This work summarizes exploratory efforts involving this method for synthesis of Mg-based materials. The TID method resulted in overall superior properties compared to conventional processing methods, while two distinct parameters (high depth of cut and low cutting speed) were found to have significant positive influence on the final material properties, and as such are considered to be suitable basis on which further exploratory work in this field may be conducted.

High performance peel grinding of steel shafts using coarse electroplated CBN grinding wheels

Grinding is widely known for its low material removal rates and high surface quality. However, recent developments in production processes for cubic boron nitride (CBN) abrasive grains have led to commercially available grain sizes larger than 300 µm. These superabrasive CBN-grains allow higher material removal rates during grinding of hardened steel components. Currently, these components are pre-machined with turning processes before hardening and finishing the work piece by grinding. However, the turning process can be eliminated by grinding with coarse CBN-grains since higher depths of cut are achievable when machining hardened components. This paper explores the limits of grinding wheels using grains with a size of B602 during soft and hard machining in comparison to conventional B252 grains. It is shown that the use of coarser grains leads to lower process forces, higher (tensile) residual stress and higher surface roughness. Residual stress and surface roughness are of less importance as these grains are to be used mainly in roughing operations with ensuing finishing operations for the required surface properties. Over all investigations, especially in hard machining, neither grain nor tool wear was observed for the B602 grains, whereas the B252 tool was severely clogged during the experiments. Additionally, the grinding force ratio indicates that the coarse grain tools have not yet reached their productivity limit as it increases over all investigated feeds. This indicates improving tool performance with lower amounts of rubbing for increasing feed rate during hard grinding and shows the potential for the industrial use of higher feed rates with larger grains.

Evaluation of surface grinding of AISI 304 stainless steel using dry and compressed air cooling techniques

The abundant use of cutting fluids in surface grinding process and the corresponding costs and energy consumption have been a major sustainability concern. This paper identified the optimum depth of cut for surface grinding under controlled grinding parameters using compressed air cooling technique and dry cutting. The surface morphology and subsurface defects of the workpiece material (AISI 304 stainless steel) were measured and compared. It was observed that lower depth of cut had a better surface morphology than higher depth of cut. The effects of compressed air on tool life were equally evaluated. The heat dissipations on the grinding wheels were observed and analysed for both grinding conditions. In addition, the influence of compressed air on the surface integrity of the workpiece was also investigated. The results showed that lower depth of cut proved to have a better quality surface compared to higher depth of cut.

Experimental investigation into tool wear, cutting forces, and resulting surface finish during dry and flood coolant slot milling of Inconel 718

Inconel 718 superalloy is a widely used material in aerospace due to its high strength, corrosion resistance, and high resistance to thermal fatigue. Excellent mechanical and thermal properties also make Inconel 718 one of the most difficult-to-machine alloys. This study aims to take a different approach of analyzing tool wear during machining of Inconel 718 by measuring worn-out area on each flute from three different faces of flute. This paper also includes analysis of cumulative tool wear, cutting forces, surface roughness, topography, burr formation, and chip morphology at various machining parameters and cooling conditions. The cutting speed was kept constant at 60 m/min due to the goal of machining at highest possible speed and the limitation in maximum spindle speed of the machine tool. Experiments were carried out in dry and flood coolant machining using uncoated carbide tools by varying depth of cut and feed rate for four different settings each. It was found that the amount of tool wear varied for different flutes when measured from top, rake, and back faces of each flute, even for the same tool. The back and rake faces exhibit more chipping wear when machining is carried out at higher depth of cut, irrespective of the cooling conditions. At the same machining conditions for the range of parameters selected in this study, flood coolant machining resulted in slightly higher tool wear at the back and rake faces of cutting flutes and generated higher cutting speed, which may be interrelated. The gradual increase in tool wear over time resulted in an increase in surface roughness from entry to exit of a 76.2 mm machined slot. Flood coolant machining resulted in slightly smoother surface finish at the lower settings of depth of cut and feed rate, while the burr formation was marginally higher in flood coolant machining during machining at higher feed rate and depth of cut. The amount of serration was found to increase specifically with the increase of feed rate and was found to be higher for dry machining compared to flood coolant machining at the same parameter settings. Finally, the new approach of tool wear analysis from different faces of individual cutting flute could provide important guidelines for predicting tool life or potential catastrophic tool failure during machining of Inconel 718.

Analysis of hybrid nanofluids in machining AISI 4340 using minimum quantity lubrication

Abstract Cutting fluids enhance the machining performance due to their ability to provide good lubrication and remove generated heat. Minimum quantity lubrication (MQL) serves as the best alternative for flood machining as it allows a considerable reduction in machining cost along with longer tool life. Nanofluids are fluids having enhanced lubrication and cooling characteristics due to very high surface to volume ratio of nanoparticles. In the present work, machining is performed in dry condition, MQL application of soluble oil without nanoparticles, 0.3 wt% of copper dispersed in soluble oil, 0.3 wt% of graphene dispersed in soluble oil, and 0.3 wt% of graphene and copper (1:1) dispersed in soluble oil (hybrid nanofluid). Turning of AISI 4340 material is performed using uncoated tungsten carbide at varying cutting parameters. Graphene nanofluid as well as hybrid nanofluid showed the least flank wear. Hybrid nanofluid showed the least cutting temperature at higher depth of cut and higher feed while copper nanofluid showed the least cutting temperature at higher cutting velocities.

Advanced machining of miniature unmanned aircraft vehicle components using nanostructured cutting tools

The advanced machining of components used in miniature unmanned aircraft vehicles is the focus of this study. The finite element method (FEM) is used to predict forces and temperatures using cutting tool inserts with a thin nanostructured film of high integrity. Similarity models are used to validate the finite element results and to understand the influence of micromachining parameters on cutting temperatures generated when machining Al 380-0 alloy. The predicted results are compared to experimental forces and temperatures using a three-dimensional piezoelectric function dynamometer and a short-range infra-red wavelength thermal camera. Nanostructured thin layer coatings lower machining forces and temperatures, which are validated through FEM predictions and experimental observations. The experimental results suggest that increasing the cutting tool’s rake angle at higher depths of cut will reduce cutting temperatures, which are predicted using the similarity models for micromachining.

Investigations on chip formation of turned novel AM alloy

Manufacturers across varied segments look for materials having appreciable machinability and surface integrities. Machinability of Mg alloys is a vital aspect during their acceptance for different applications. The chip shape generated in the cutting operation is a crucial attribute dominating the surface roughness, besides the dimension’s precision and the tool lifespan. The study discusses the chip-formation through the dry turning of a novel AM alloy (Mg alloy with 7 wt%Al-0.9 wt%Mn) using carbide insert with a 0.4 mm nose radius. During the experiments, three chip dimensions, namely chip-thickness, chip-length, and chip-width were measured. The turning variables, namely cutting speed( v), depth of cut (DOC), and feed ( f) is altered and applied to the workpiece. The chip shape was mostly dependent on the grouping of turning parameters. It was seen that favorable continuous chip formed at high feed and low DOC. The % contribution of each turning parameter on the chip shape was calculated. The experimental results are validated with the help of analysis of variance (ANOVA). The results show that the % contribution of feed, speed, and DOC on chip-thickness is 58.49%, 28.91%, and 12.49%; the contribution on chip-length is 76.89%, 20.81%, and 2.23%; and on chip-width, it is 25.28%, 0.48%, and 74.33%, respectively. Further, the chip shapes were compared with the shapes that were predicted by FEM software. The study offers vital insights for parameter selection to improve chip shape, which, in turn, contributes to higher surface quality.

Semi-empirical model for depth of cut in abrasive waterjet machining of metal matrix composites

Abrasive waterjet machining (AWJM) is one of the versatile unconventional machining processes presently followed in several industries in the machining of variety of engineering materials. Achieving maximum depth of penetration is a prime requirement to achieve higher productivity. As the AWJM involves several process variables, selecting the right combinations of process variables to achieve maximum depth of cut (h) is a cumbersome and time-consuming process. Thus, scientific way of choosing process variables is being attempted by many researchers through suitable modeling techniques. This paper focuses on the development of semi-empirical model using Buckingham’s π theorem to predict the depth of cut (h) during AWJM of unreinforced and reinforced aluminum metal matrix composites (MMCs) and is compared with regression model and experimental data. Experiments were designed according to Box–Behnken method, and cutting trials were performed on unreinforced aluminum and 5%, 10% and 15% volume fraction of boron carbide (B4C)-reinforced 6063 aluminum alloys, MMCs by keeping the process parameters of water pressure (p), mesh size (ms), mass flow rate (ma) and traverse speed (u) each at three levels. The experimental results of depth of cut (h) at different levels of process parameters were analyzed through ANOVA. Based on the experimental results, the combinations such as #80 mesh size, 340 g/min mass flow rate, 200 MPa water pressure and 60 mm/min traverse speed, resulted in higher depth of cut (h). The experimental, semi-empirical and regression models were compared. The models’ predictions are in good agreement with the experimental data under the corresponding conditions.

Turning experiment of Ti-6Al-4V by using uncoated carbide insert

Titanium alloy Ti-6Al-4V is widely being used in the blades, discs, rings, airframes, fasteners, components, vessels, cases, hubs, forgings and biomedical implants. Nevertheless, the properties of titanium alloys which are low thermal conductivity, low modulus of elasticity and high chemical activity cause it very difficult to machine. Excessive elevated temperature due to low thermal conductivity of these alloys make it favorable for tool wear. In this paper, an experiment using orthogonal array L4 is conducted to explore the effect of cutting parameters e.g. cutting speed, depth of cut and feed rate in terms of surface roughness and tool wear. The cutting tool uncoated carbide is used in performing orthogonal cutting of Ti-6Al-4V in this study. It is found low cutting speed, feed rate and high depth of cut is favourable in producing good Ra and minimum flank wear.

Effects of Turning Parameters and Parametric Optimization of the Cutting Forces in Machining SiCp/Al 45 wt% Composite

Cutting force in the machining process of SiCp/Al particle reinforced metal matrix composite is affected by several factors. Obtaining an effective mathematical model for the cutting force is challenging. In that respect, the second-order model of cutting force has been established by response surface methodology (RSM) in this study, with different cutting parameters, such as cutting speed, feed rate, and depth of cut. The optimized mathematical model has been developed to analyze the effect of actual processing conditions on the generation of cutting force for the turning process of SiCp/Al composite. The results show that the predicted parameters by the RSM are in close agreement with experimental results with minimal error percentage. Quantitative evaluation by using analysis of variance (ANOVA), main effects plot, interactive effect, residual analysis, and optimization of cutting forces using the desirability function was performed. It has been found that the higher depth of cut, followed by feed rate, increases the cutting force. Higher cutting speed shows a positive response by reducing the cutting force. The predicted and experimental results for the model of SiCp/Al components have been compared to the cutting force of SiCp/Al 45 wt%—the error has been found low showing a good agreement.

Evolution of chemo-mechanical effects during single grit diamond scratching of monocrystalline silicon in the presence of potassium hydroxide

Efficiency and workability of silicon wafers for various applications depend on theirs surface integrity and damage free structures. Productivity of mechanical processing on silicon wafers is always limited by occurrence of cracks and brittle mode material removal at high depth of cut. This study presents a method of using controlled concentration of KOH solution during diamond micro-scratching of silicon and investigates the chemo-mechanical effects of KOH solution with respect to cutting speed. To establish the chemo-mechanical theory of cutting, responses of physical and material properties of silicon in presence of KOH solution are captured and correlated with mechanical responses during micro-scratching. Zeta potential and nanohardness are greatly reduced in KOH environment. Ductile mode is found to be extended by using 10 wt% KOH. Crack/chipping length is observed to be first increasing with increase in cutting speed at low range (0.6–20 mm/min) and then decreasing on further increase in the cutting speed (20–200 mm/min). Stability in cutting force signature and behavior of material flow along the scratch length is also found to be improved by using KOH. Adhesive wear and abrasive wear are found to be the main forms of single grit wear, which is significantly reduced in the presence of KOH. The experimental results on different mechanical and physical phenomena in this study are of great importance for establishing the theoretical insight into material removal behavior and selection of machining parameters during micro-machining of silicon wafer.

Experimental Investigation and Optimizing Geometrical Characteristics and Surface Quality in Drilling of AISI H13 Steel

The aim of this paper is to investigate and optimize surface quality and geometrical characteristics in drilling process of AISI H13 steel, because they are critical items for precision manufacturing. After conducting the experiments, two regression models are developed to extensively evaluate the effect of drilling parameters on process outputs. After that, evolutionary multi-objective optimization algorithm is employed to find the optimal drilling conditions. Non-dominated Sorting Genetic Algorithm (NSGA-ІІ) is developed and regression functions are taken into account as objective functions of algorithm to simultaneously optimize the surface roughness and deviation of circularity. The optimization results are successfully in agreement with experimental findings and finally the set of optimal drilling conditions is reported that can be selected by process engineer according to the priority and application. It is shown that, an increase in Cutting speed and liquid coolant intensity decreases the surface quality, while higher depth of cut, tool diameter and reed rate improve it. It is also found that tool diameter and depth of cut are the most effective input parameters on deviation of circularity. Finally, it can be concluded that, the implemented approach in this research provides an efficient method for other manufacturing processes to increase the performance and reduction of production costs.

Hybrid Edge–Cloud-Based Smart System for Chatter Suppression in Train Wheel Repair

The contact profile of a train wheel has a key role in its operation performance. Rolling smoothly and with reduced resistance results in an increase in the efficiency and safety of rail transport. The original shape and dimensions of the profile of the wheel are altered under operation of the train, especially due to braking events and the presence of external objects between the wheel and the railway. With the purpose of recovering the optimum contact profile, train wheels are periodically machined using special lathes. This repair operation is particularly critical in freight trains, which are only reshaped a few times throughout their service life and, therefore, high depths of cut are required to recover the wheel in a productive way. As the presence of chatter vibrations limits the productivity of these operations, a hybrid edge–cloud computing approach has been developed for chatter vibration suppression. An expert system based on automatic chatter detection and suppression has been developed in the edge. The expert system is based on continuous real-time vibration monitoring and combines continuous spindle speed variation (CSSV) and cutting speed reduction to suppress chatter. Cloud computing is used to extract wheel profile machining fingerprints and obtain insights from multiple aggregated machined wheels. An industrial implementation of the system is described in the present work.

Study The Effect of Process Parameters of CNC Milling Surface Generation Using Al-alloy 7024

A wonderful unique research developments in modeling surface roughness and optimization of the predominant parameters to get a surface finish of desired level since only suitable selection of cutting parameters can get a better surface finish, so the objective of this work is to study the milling process parameters which include tool diameter, feed rate, spindle speed, and depth of cut resulting in optimal values of the surface roughness during machining AL-alloy 7024. The machining operation implemented on XK7124 3-axis CNC milling machine. The effects of the selected parameters on the chosen characteristics have been accomplished using Taguchi’s parameter design approach. The parameters considered are – depth of cut with two levels (0.2, 0.5 mm), tool diameter with two levels (6, 8 mm), spindle speed with two levels (1000, 2500 rpm), and finally feed rate with two levels (200, 500 mm/min). Analysis of the results showed that the optimal settings for low values of surface roughness are large tool diameter (8 mm), high spindle speed (2500 r.p.m), low feed rate (200 mm/min) and high depth of cut (0.5 mm). Response Table for mean of surface roughness showed that tool diameter has the most effected factors (rank one) followed by feed rate (rank two) then depth of cut which is the third effected factors and finally spindle speed with the less effected factors of surface roughness (rank four).

Analysis and simulation of process damping in HPC milling

The use of tools with chamfered cutting edges is an essential part of high performance cutting (HPC) as a rough milling process strategy for manufacturing structural components in the aerospace industry. Due to an interaction between the chamfer and the undulated workpiece surface, tool vibrations can be damped allowing high depths of cut without the occurrence of harmful dynamic effects. Hence, a significant increase in efficiency is possible. As a result of process damping, the stability boundary predicted by linear stability analysis provided for instance by analytical or geometric physically-based simulations will generally underestimate the experimentally determined one. Consequently, the object of this procedure, namely to reduce the number of test runs until sufficient process parameter values are determined, could not be met. Therefore, the damping effect induced by chamfered tools was analysed in this paper. It is shown that the use of chamfered cutting edges leads to a significant limitation of chatter amplitudes when exceeding the stability limit. The strength of this effect depends on the cutting speed and the engagement situation, which influence the intensity and number of interactions between the chamfer and the workpiece surface and, thus, the resulting process damping. Moreover, a dynamic process damping model presented in the literature was chosen and implemented in a geometric physically-based milling simulation. An evaluation of its validity points out the challenges regarding the simulation of process damping.