Different Depths Of Cut Research Articles

Experimental investigation into effects of natural stone properties on performance of a chisel tool

ABSTRACT The main purpose of this study is to determine how the linear cutting experiments should be performed on natural stones to better understand the stone cutting and predict cutting performance parameters from easily obtainable rock properties. A compiled database including thirty-four different natural stone samples in metamorphic, sedimentary and igneous geological origins is used to investigate the relationships between specific energy, mean normal and cutting forces and eleven different macro and micro properties of natural stones collected from quarries around Turkey. Linear cutting tests are performed by a portable linear cutting machine with a simple chisel tool at four different depths of cut in unrelieved (non-interactive) cutting mode. The difference in this study from previous investigations is the wide variety of stone samples with different characteristics to better explain the cutting mechanisms of natural stones. The results indicate that Shore scleroscope hardness and texture coefficient can be used to predict cutting performance parameters of natural stones. Additionally, using shallower depths of cut in linear cutting tests could lead to a better explanation of specific energy of natural stones.

Comparative analysis of cutting characteristics of simulated and bovine cortical bone

Simulated bone is widely used for surgical simulation, medical training, and especially for medical cutting device testing due to its mechanical properties similar to those of natural bone. However, studies on its cutting characteristics are still limited, especially for the simulated cortical bone. The cutting characteristics of natural cortical bone are often influenced by viscoelasticity and bone fiber structure that affect chip formation, as well as the variation of cutting forces at different cutting speeds or different depths of cut. In this work, orthogonal cutting experiments were performed on simulated cortical bone to investigate chip formation with cutting force variations and compared with bovine cortical bone. Experimental results show that the simulated cortical bone is similar to bovine cortical bone in viscoelasticity. Simulated bone has a relatively homogeneous composition with a simple hierarchy. Therefore, the difference in cutting force at small and large cutting depths is less significant than in natural cortical bone. In addition, because the glass fibers in simulated bone are randomly distributed, they do not accurately reflect the anisotropic properties of natural cortical bone. These findings can contribute to an in-depth understanding of the behavior of simulated bone during the cutting process and guide the improvement of simulated bone to better emulate the cutting characteristics of cadaveric bone for better application in the medical field.

Cutting performance and failure mechanisms of TiB2-TiC-Al2O3 multi-dimensional gradient ceramic tool in intermittent turning of hardened steel

The TiB2-TiC-Al2O3 multi-dimensional gradient ceramic tool (MDGCT), whose composition varied in two directions, were designed and fabricated via hot-pressed vacuum sintering. The cutting performance, including cutting force, cutting temperature and chip morphology, and failure mechanisms of MDGCT with different orientation angles in intermittent turning of SKD11 hardened steel were investigated in comparison with the homogeneous commercial ceramic tool CC650 at different depths of cut and cutting speeds. And the distribution of thermal residual stress of MDGCT was investigated employing FEM analysis. Results showed that the multi-dimensional gradient ceramic tool with orientation angle of 15 degree (TT3A15) had the optimal comprehensive cutting performance. The main failure mechanisms of CC650 tool were chipping and fracture caused by crack propagation, while the crack propagation was effectively inhibited in the TT3A15 tool, and its failure mechanism was chipping at the tool nose. The contribution of multi-dimensional gradient structure of TT3A15 tool to the increasing residual compressive stress of minor cutting edge, the favorable anti-crack capacity of flank face and the heterogeneity of physical and mechanical properties of rake face were responsible for its optimal cutting performance.

XRD analysis and surface roughness of AL2024 alloy produced through P/M route and machined by using CNC milling machine

The purpose of this analysis is to examine the surface roughness during machining of aluminum 2024 prepared through the powder metallurgical (P/M) route. Aluminium 2024 alloy is prepared with different compositions, such as pure Al, 1.5 W% of Mg, and 2–6% of Cu powders. Powders are blended with the ball milling machine according to the composition required, and green compacts are prepared in a square-shaped die (25*25mm) by applying a uniaxial load of 250 Mpa ±50. The sintering process was performed at a temperature of 594 °C for 60 minutes, and the heating profile consisted of a 10-minute isothermal keep at 594 °C followed by cooling in Furness. It presents and addresses compaction characteristics, green density, dimensional changes during sintering, sintering density, mechanical properties, and microstructures. Also determined were the surface roughness and MRR during machining with a CNC milling machine at different depths of cut.

Experimental, Numerical and Statistical Investigation of Cutting Force in the Machining of AISI H13 Hot Work Tool Steel

Bu çalışmada, seramik kesici takımlar ile AISI H13 sıcak iş takım çeliğinin tornalanmasında kesme parametrelerinin kesme kuvveti üzerindeki etkileri araştırılmıştır. Tornalama deneyleri, üç farklı kesme hızında (120, 180 ve 240 m dak-1), üç farklı ilerleme miktarında (0.12, 0.15 ve 0.18 mm dev-1) ve üç farklı talaş derinliğinde (0.6, 1 ve 1.4 mm) kuru kesme şartlarında CNC torna tezgahında gerçekleştirilmiştir. Aynı zamanda, tornalama simülasyonları da sonlu elemanlar analizine (FEA) dayalı olarak Third Wave AdvantEdge yazılımı ile gerçekleştirilmiştir. Deneysel ve nümerik analizler ile elde edilen kesme kuvveti verileri, Taguchi methodu, Anova ve regresyon analizleri kullanılarak istatistiksel olarak analiz edilmiştir. Analiz sonuçları her iki yöntem ile elde edilen esas kesme kuvveti (Fc) değerleri üzerinde sırasıyla %80.97 ve %80.32 katkı oranları ile en etkin parametrenin talaş derinliği olduğunu göstermektedir. Dahası, tornalama simülasyonlarında ve deneysel olarak elde edilen esas kesme kuvveti (Fc) değerleri arasında ortalama %9'lik bir fark elde edilmiştir ve her iki yöntem ile elde edilen Fc değerleri için optimum parametre grubu A3B1C1 (kesme hızı = 240 m dak-1, ilerleme miktarı = 0.12 mm dev-1 ve talaş derinliği = 0.6 mm)’dir.

Optimization of Cutting Parameters Affecting Cutting Force and Surface Roughness in Machining of AISI P20 Die Steel

This study focuses on optimizing cutting parameters effective on cutting force (Fc) and surface roughness (Ra) in the machining of AISI P20 steel. The turning experiments have been performed in CNC lathe at three different cutting speeds (Vc) (120, 180, and 240 m/min), three different feed rates (f) (0.12 0.21 and 0.3 mm/rev), and three different depths of cut (a) (0.4, 0.8, and 1.2 mm) according to Taguchi L9 orthogonal array. The effect levels of the cutting parameters on Fc and Ra have been determined with analysis of variance (Anova). The analysis results indicate that the depth of cut is the most significant parameter affecting Fc while the feed rate is the most significant parameter affecting Ra. Moreover, the result analysis shows that cutting speed of 240 m/min, feed rate of 0.12 mm/rev, and depth of cut of 0.4 mm) factor levels were the optimum cutting parameters for the output parameters (Fc and Ra). In turning experiments performed at optimum cutting parameters, the lowest Fc and Ra values were measured as 178N and 0.412 µm, respectively.

Numerical modelling of size effects in micro-cutting of f.c.c. single crystal: Influence of strain gradients

A size effect is exhibited by metals in cutting processes at small scales: a nonlinear escalation in the cutting energy per unit volume with a decrease in the thickness of the uncut chip. To understand this phenomenon, a numerical model of orthogonal micro-cutting of f.c.c. single-crystal copper was developed, and three different depths of cut (0.8 μm, 1.4 μm and 2.0 μm) were considered. Enhanced models of crystal plasticity (EMCP) and strain-gradient crystal plasticity (EMSGCP) implemented in ABAQUS/Explicit through a VUMAT Fortran subroutine were used. Obtained results were compared with the experiments reported in the literature. The influence of size effect on deformation response of a single-crystal material was investigated extensively in terms of the distribution of field variables such as strain gradients, stresses, lattice rotations and activity of different slip systems. The influence of crystallographic orientation was also studied. It was observed that the size-effect phenomenon was predicted more accurately with the EMSGCP theory, where polar dislocations evolving during deformation were found to affect it significantly.

Post-processing of additive manufactured parts: a numerical strategy applied in maxillary implantology

To obtain a functional part from additive manufacturing (AM) technologies, some surfaces require post-processing by machining. An approach is developed using additive manufacturing supports as a clamping device for the milling operation. A model combining an analytical approach to determine the cutting forces with a finite element model (FEM) to predict the dynamical response of the workpiece-supports system is proposed. The complex structure of the supports is homogenized with a simplified geometry with equivalent stiffness and mechanical properties. A case study from the biomedical field is proposed: the finishing operation of a custom-made maxillary reconstruction plate is simulated. A parametric study is proposed with: (1) two different lattice geometries used as support structures; (2) up and down milling; (3) different depths of cut.

Effect of Graphene Nanoplatelets Reinforcement on Grindability of Zirconium Diboride Ceramics

Abstract The effect of graphene nanoplatelets (GNPS) on the grindability of GNP reinforced ZrB2 was studied using a resin bonded diamond grinding wheel under dry and wet conditions. A comparative study of grinding forces was performed at selected wheel surface speeds and depths of cut for surface grinding. ZrB2-GNP showed lower normal grinding forces due to the improved fracture toughness and reduced hardness. The presence of GNP reinforcement in ZrB2 resulted in lower tangential forces and reduced specific grinding energy due to the role of GNP as a solid lubricant. The measured forces showed a good correlation with the micro cutting model for ZrB2 and ZrB2-GNP under dry conditions. The tangential forces showed the same trend as normal forces at different depths of cut and wheel surface speeds for ZrB2 and ZrB2-GNP with average force ratios of 0.3 and 0.35, respectively. The presence of porosity in ZrB2 increased the normal grinding forces during wet grinding. Scanning electron microscope (SEM) images of the grinding chips indicated a mixture of both the ductile mode and the brittle mode of material removal with predominantly brittle fractured chips. Energy-dispersive spectroscopy (EDS) confirmed the presence of GNPs in ZrB2-GNP grinding chips. The topography of the grinding wheel showed higher wheel loading after the dry grinding than that of wet grinding. The wet grinding resulted in relatively lower surface roughness (Ra values) than dry grinding.

Experimental Investigation on Surface Roughness and Metal Removal Rate of Aluminium 2024 Alloy

Abstract: The purpose of this work is to investigate experimentally the surface roughness and MRR while machining of aluminium 2024 alloy which is prepared by powder metallurgical technique. Aluminium 2024 alloy prepared with different composition such as Pure Al, 1.5 W% of Mg and 2-6 % of Cu powders. Powders are blended with ball milling machine according to the composition required and specimens are prepared in square shape die (25*25mm) by applying uniaxial load of 200Mpa. The sintering process was performed at 594 0C for 60 min and cooled at room temperature. SEM and XRD analysis was carried out to know various characteristics like green density, dimensional changes during sintering, sintering density, mechanical properties and microstructures. Finally the Surface roughness and MRR during machining with CNC milling machine at different depth of cuts was also evaluated. Keywords: Aluminium 2024 alloy, surface roughness, MRR, SEM and XRD analysis

Modeling of cutting forces while boring heat – resistant alloy Inconel 718

In this work, authors had made computer FEM (finite element method) simulation of machining holes in part made of heat-resistant alloy Inconel 718. For this simulation nonlinear solver LS – Dyna had been used. Material type for physical modeling of workpiece have been selected to Johnson – Cook formulation. Tool configuration is rigid and have dynamic stiffness in three dimensions in the fastening points. Graphs of cutting forces and moments of cutting for three different depths of cut had been obtained. In the beginning of the cutting, in addition to the smooth increase of cutting forces, high – frequency oscillations with amplitudes of 1 – 3 N also take parts. The resulting cutting force has pronounced harmonic oscillations at low frequencies. The maximum burst of amplitude occurs in the period from 0.9 to 1.3 seconds from the start of cutting. It is recommended to carry out a smooth increase of cutting forces at this time through cutting modes. High – frequency oscillations, which were insignificant in the context of each component of the cutting forces, due to the summation and oscillations of the holder play a crucial role in the oscillations of the boring moment.

Investigation of the Relationship between Schimazek's F-Abrasiveness Factor and Current Consumption in Rock Cutting Process

Predicting the current consumption of cutting machines in cutting building stones can be one of the most fundamental steps to achieve optimal conditions from energy consumption in the building stone cutting industry. Therefore, it is necessary to study the relationship between the operational characteristics of the machine and the work piece with the amount of consumed energy by the machine. In this paper, an attempt has been made to provide a precise model for predicting the current consumption of cutting machines using statistical studies. For this purpose, laboratory studies were performed under different operational conditions such as different depths of cut (15, 22, 30, and 35 mm) and different feed rates (100, 200, 300, and 400 cm/min). During the sawing process, 12 samples of soft and hard rock were studied by using a cutting machine on a laboratory scale (with the ability to change machining parameters and equipped with measuring current consumption). Following laboratory studies, rock samples were transferred to the rock mechanics laboratory to determine Schimazek's F-abrasiveness factor. After determining the abrasion of the samples, statistical studies were performed by using the SPSS software. Thus, the new statistical models were presented to predict the current consumption of the cutting machine based on the abrasion of the building stone sample, cutting depth, and the progress rate of the workpiece as an independent variable. The proposed statistical models can be used with high reliability to estimate the current consumption in the cutting process.

Energy expenditure measured for various tillage practices for various speeds of operation at different depths of cut in two different soil types

Tillage involves a lot of energy expenditure, generally in terms of fuel consumed by the tractor. The fuel consumption for the different tillage practices needs to be quantified and this paper presents quantification for the same. The experiment was carried out at the fields of two different soil types viz. sandy loam (S1) and silty loam (S2). Six tillage practices, designated as P1, P2, P3, P4, P5 and P6, were undertaken in the present study. The six practices were one pass of harrow-cultivator-planker combination (P1), two passes of harrow-cultivator-planker combinations (P2), one pass of rotavator (P3), two passes of rotavator (P4), one pass of spading tillage machine (P5) and two passes of spading tillage machine (P6). Different implements have their own, i.e. different recommended speeds and depths of operation. For experimental study, two different depth of cut ranges, designated as D1 & D2 and two forward velocity ranges, designated as V1 & V2, suitable to every implement, were selected. The conventional tillage practices consumed more fuel and time as compared to multi-powered tillage tools practices but were found to move considerable volume of soil and shows lower rate of fuel consumption per unit of soil moved than other practices, whereas, rotavator and spading machine takes lesser time and fuel for tillage operation.

Development of a frictionally damped boring bar for chatter suppression in boring process

A novel boring bar was developed for chatter reduction of machining processes. By proposing an internal frictional damping structure, additional energy dissipation during bending vibrations was imposed to the boring bar. The structure consisted of some pins longitudinally press-fitted inside the boring bar. This structure resisted against bending of the boring bar during machining processes. After introducing the structure, an analytical model was presented to determine the amount of energy dissipated by the damper. Using the analytical model and finite element modeling (FEM), the most effective configuration was obtained for the proposed frictional damper structure. After determining the best configuration, a damped boring bar specimen was fabricated for experimental comparison with a regular boring bar. The modal and cutting tests were performed on the specimens. The modal test revealed a significant increase in the structural damping of the boring bar. The cutting tests were performed at different depths of cut and different spindle speeds, and the process was investigated through sound analysis and surface finish observation. Experimental comparisons indicated the higher performance of the proposed tool.

Analysis of Surface Roughness, Sound Level and Machine Current in the Turning of Hardened AISI S1 Steel

In this study, surface roughness values, sound levels and instantaneous current values were measured with calibrated devices in accordance with the experimental parameters. In this study, turning tests were carried out on AISI S1 steel material workpieces at three different depth of cuts, three different feed rates and 3 different cutting speeds without coolant. A full factorial experimental design method was used. Three different cutting speeds (135, 155, 175 m/min), feed rates (0.045, 0.090, 0.135 mm/rev) and depth of cuts (0.04, 0.08, 0.12 mm) as control factors have been selected. The effect levels on the surface roughness of the control factors with analysis of variance (ANOVA) performed using the experimental results were determined. Finally, the confirmation tests were performed and showed that the analysis is successfully implemented. As a result of analysis, the most effective cutting parameter on all the output parameters was found to be the feed rate. Its influence on the sound level was found to be 60.26%. The feed rate was followed by the cutting speed (22.87%) and the depth of cut (6.58%), respectively. The motor current values were influenced by feed rate, cutting speed and depth of cut by 52.71%, 18.73% and 23.88%, respectively.

Experimental studies using a new portable linear rock cutting machine and verification for disc cutters

This study aims at verifying the experimental results of a newly developed portable linear rock cutting machine (PLCM) and its usability for proper selection, design and predicting performance of TBMs instead of full-scale rock cutting machine. PLCM minimizes some of the disadvantages of full-scale linear rock cutting machine (FLCM) such as requiring experienced manpower to run the tests, large blocks of rock samples, which are usually difficult to obtain and expensive, and time consuming procedures. Relieved and unrelieved cutting tests at different depths of cut are performed in this study on different rock samples with the PLCM by using a mini-scale constant cross-section (CCS) disc cutter having a diameter of 145 mm and a tip width of 4.7 mm and the FLCM by using a real-life CCS disc cutter having a diameter of 432 mm and a tip width of 12 mm. Line spacing is 20 mm for mini scale disc cutter and 60–80 mm for real-life disc cutter in cutting tests in relieved mode. The results from both of the experimental devices are correlated for using prediction of cutting performance parameters of FLCM, which is commonly preferred and well-proven testing device for predicting the performance of any type of mechanical miner excavating hard rock. Then, another set of rock sample is obtained from Uskudar-Umraniye-Cekmekoy (UUC) metro tunnel construction site using EPB TBMs, of which their field performance (penetration and/or cutting rate, specific energy) and operational parameters (TBM thrust, cutterhead torque, power and rotational speed) are recorded. Based on the PLCM tests performed on the samples obtained from the field, the performance of the TBM is estimated theoretically (deterministically) and compared with the realized field performance to verify the results of the PLCM tests. The results indicate that the experimental cutting performances of the PLCM and the FLCM are well correlated and the PLCM can be used for predicting performance, design and selection of TBMs excavating hard rocks. Additional studies are required for developing more reliable models for predicting excavation performance.

Predict the flow stress of the hardness for AISI 4340

Micro-machining technology has gradually become the frontier and hotspot of modern scientific research. The flow stress described by high strain, strain rate, and temperature is usually applied to simulate the machining process under various conditions. In this work, a novel method to predict the flow stress for various hardness of AISI 4340 was proposed using the micro-milling process simulation. The phase fraction for different hardness is calculated combined with a Johnson-Cook (JC) constitutive model to develop flow stress mathematics model, and then the model is modified and used to simulate the micro-milling process and predict the cutting force in different depths of cut. All results showed a good agreement with the experimental data. The research also provides a reference method for predicting the flow stress of other materials.

Investigation on the effect of machining parameters on surface roughness during turning of kenaf fiber-reinforced composite using non-contact vision method

Machinability studies on natural fiber-reinforced composites (NFRCs) in the past have been limited mainly to drilling. There is limited work published on the effects of machining parameters on the surface finish quality during turning of NFRCs. The objective of this research is to investigate the effects of spindle speed and feed rate on the surface finish quality of kenaf fiber-reinforced composites during turning. A non-contact machine vision method was used to determine the surface roughness parameters. The image of the edge profile of each composite specimen after machining was captured using a high-resolution digital camera with the aid of backlighting. The edge profiles were extracted to sub-pixel accuracy from the digital images. Six roughness parameters were determined from each extracted profile and plotted against feed rate. The results show that high spindle speed generally produced poor quality surface finish at all feed rates tested. This was mainly due to the centrifugal forces caused by the high rotational speed of the workpiece, which tends to stretch out the loose uncut fibers radially. Different depths of cut were found to produce different surface roughness depending on whether the cutting tool passes fully through, partially, or in-between the fiber bundles. Better surface finish was obtained at low spindle speeds and low feed rates when the tool passes mainly in-between the fiber bundles.

Determination of Ideal Cutting Conditions for Maximum Surface Quality and Minimum Power Consumption During Hard Turning of AISI 4140 Steel Using TOPSIS Method Based on Fuzzy Distance

In this study, hard turning tests are carried out on the hardened AISI 4140 steel material. Power consumption, sound intensity, processing time and surface roughness values are measured for all combinations of cutting conditions such as three different cutting speeds, three different feed rates, three different depths of cut and two different tool cutting edge angle. According to these measurements, the ideal cutting condition is found by using the TOPSIS method which is integrated by fuzzy Hamming distance, Euclidean distance and Hausdorff distance measure methods. Also in case that machinability parameters have different importance degrees, ideal cutting condition is determined by using the weighted fuzzy distance measure method. According to the experimental results obtained, it is observed that the surface roughness value increased with the increasing feed rate. Roughness values obtained at 90 degree tool cutting edge angle are lower than 62.5 degrees. It is observed that the sound intensity increases with the increasing feed rate. The machining time is reduced with increasing feed rate, depth of cut and cutting speed. Thus, total power consumption is reduced.

ANALYSIS OF THE RELATION BETWEEN FRACTAL STRUCTURES OF MACHINED SURFACE AND MACHINE VIBRATION SIGNAL IN TURNING OPERATION

Investigating about the machined surface is an important issue in every machining operation. One of the factors that affect the quality of machined surface is the vibration of machine that is caused by different parameters such as the spindle speed. Therefore, the analysis of the relation between the machine vibration and surface quality of machined surface is very important. In this research, we analyze the relation between the machined surface and machine vibration from the complexity point of view. For this purpose, we employ fractal analysis. We investigate the variations of fractal structure of vibration signal collected from lathe machine versus the variations of fractal structure of the machined surface, for different depths of cut, feed rates and spindle speeds. Based on the obtained results, the variations of fractal structures of machined surface and vibration signal show a similar trend with the variations of depth of cut and feed rate, where by the increment of depth of cut and feed rate, vibration signal and machined surface get more complex. However, the obtained results in the case of variation of spindle speed do not show a consistent trend between variations of fractal structures of vibration signal and machined workpiece. The obtained method in this research can be applied to other machining operations in order to analyze the relation between the complexities of machine vibration and machined surface.