Cutting Tool Temperature Research Articles

Transient Temperature at Tool-Chip Interface during Initial Period of Chip Formation in Orthogonal Cutting of Inconel 718.

Machining nickel-based super alloys such as Inconel 718 generates a high thermal load induced via friction and plastic deformation, causing these alloys to be among most difficult-to-cut materials. Localized heat generation occurring in machining induces high temperature gradients. Experimental techniques for determining cutting tool temperature are challenging due to the small dimensions of the heat source and the chips produced, making it difficult to observe the tool-chip interface. Therefore, theoretical analysis of cutting temperatures is crucial for understanding heat generation and temperature distribution during cutting operations. Periodic heating and cooling occurring during cutting and interruption, respectively, are modeled using a hybrid analytical and finite element (FE) transient thermal model. In addition to identifying a transition distance associated with initial period of chip formation (IPCF) from apparent coefficient of friction results using a sigmoid function, the transition temperature is also identified using the thermal model. The model is validated experimentally by measuring the tool-chip interface temperature using a two-color pyrometer at a specific cutting distance. Due to the cyclic behavior in interrupted cutting, where a steady-state condition may or may not be achieved, transient thermal modeling is required in this case. Input parameters required to identify the heat flux for the transient thermal model are obtained experimentally and the definitions of heat-flux-reducing factors along the cutting path are associated with interruptions and the repeating IPCF. The thermal model consists of two main parts: one is related to identifying the heat flux, and the other part involves the determination of the temperature field within the tool using a partial differential equation (PDE) solved numerically via a 2D finite element method.

Leveraging IoT in Auto Component Manufacturing to Monitor Surface Roughness and Tool Temperature

Surface finish is an important requirement in Auto Component Manufacturing that defines the quality of work piece obtained from turning operations. Thus to reduce downtime due to rejection of work piece for its surface finish a continuous monitoring of surface roughness based on its cutting parameter and vibration signal is required. Similarly it is also important to monitor the cutting tool temperature to have a longer tool life. With the emerging trend of Internet-of-Things (IoT) it has become very easy to collect the required data, storing it, analysing it and also alerting the required personnel through the mobile application, e-mail and SMS. The stored data and analysis could reveals in depth the process, which leaves a large scope for improvement of the system. The paper discusses the implementation of IoT to collect data of vibration signal and cutting tool temperature of dry turning operation, for cutting parameter like 1) spindle speed 2) feed rate and 3) depth of cut for three different material mild steel (MS), brass and aluminium (Al). A correlation was obtained to predict surface roughness and tool temperature. The system developed could give a real time monitoring of surface roughness on a smart phone that can be used as a tool for optimizing the turning process to give improved quality and increased production volume.

Leveraging IoT in Auto Component Manufacturing to Monitor Surface Roughness and Tool Temperature

Surface finish is an important requirement in Auto Component Manufacturing that defines the quality of work piece obtained from turning operations. Thus to reduce downtime due to rejection of work piece for its surface finish a continuous monitoring of surface roughness based on its cutting parameter and vibration signal is required. Similarly it is also important to monitor the cutting tool temperature to have a longer tool life. With the emerging trend of Internet-of-Things (IoT) it has become very easy to collect the required data, storing it, analysing it and also alerting the required personnel through the mobile application, e-mail and SMS. The stored data and analysis could reveals in depth the process, which leaves a large scope for improvement of the system. The paper discusses the implementation of IoT to collect data of vibration signal and cutting tool temperature of dry turning operation, for cutting parameter like 1) spindle speed 2) feed rate and 3) depth of cut for three different material mild steel (MS), brass and aluminium (Al). A correlation was obtained to predict surface roughness and tool temperature. The system developed could give a real time monitoring of surface roughness on a smart phone that can be used as a tool for optimizing the turning process to give improved quality and increased production volume.

Real Time Cutting Tool Temperature Monitoring in Lathe Turning of AISI 1018 Steel using IoT applications with Arduino

Real Time Cutting Tool Temperature Monitoring in Lathe Turning of AISI 1018 Steel using IoT applications with Arduino

Minimum Quantity Lubrication An emerging technology for sustainable development

The machining of metals has traditionally involved the use of large quantities of water and oils for dissipating the cutting tool temperature, improving the surface finish of parts and increasing tool life. Invariably, the cutting fluid has become contaminated with use, has required being environmentally disposed and has accounted for approximately 17% of the total production cost of parts. The purpose of this article is to review the relevant literature in machining using minimum quantity lubrication particularly as it pertains to environmental and health issues and outline future potential research in this technology. The findings of this study show that MQL may be an economical and environmentally compatible lubricationtechnique. Keywords—MQL, cutting fluid, sustainability.

Real-Time Cutting Temperature Measurement in Turning of AISI 1045 Steel through an Embedded Thermocouple—A Comparative Study with Infrared Thermography

During machining processes, a high temperature is generated in the cutting zone due to deformation of the material and friction of the chip along the surface of the tool. This high temperature has a detrimental effect on the cutting tool, and for this reason, it is of the utmost importance to assess the cutting temperature in real time during these processes. Despite all the advances and investigation in this field, accurately measuring the cutting temperature remains a great challenge. In this sense, this work intends to contribute to solving this problem by experimentally evaluating the potential of the developed approach for embedding thermocouples into the rake face of cutting tools for measuring cutting temperature in real time during dry turning of AISI 1045 steel for different cutting parameters and comparing the obtained results with infrared thermography measurements at the exact same point. A well-defined, smooth micro-groove with good surface quality was produced by laser surface modification. Then a laser-welded K-type thermocouple was fixated in the micro-groove with a MgO ceramic adhesive, ensuring protection from wear and chips, which allowed the creation of WC-Co cutting inserts with the ability to measure cutting tool temperature with a maximum error of 0.96%. Results showed that, despite yielding the same trend, the tool temperature measured by the IR thermographic camera was always lower than the temperature measured by the K-type embedded thermocouple. The proposed embedded thermocouple method proved to be a reliable, precise, accurate, and cost-effective approach for real-time temperature measurement capable of providing useful information for cutting parameter optimization, thus allowing increased productivity and tool life.

Computational Fluid Dynamics Simulation on Thermal Performance of Al/Al2O3/SWCNT Nanocoolants for Turning Operations.

The objective of this study is to numerically investigate the thermal performance of cutting fluids dispersed with nanoparticles for effective heat removal during turning operations. The simulations are performed using Ansys Fluent software, and the problem is modelled as a three-dimensional turbulent incompressible single-phase flow. The computational domain consists of a heated cutting tool and work piece, and nanocoolants are sprayed from a nozzle located above the machining zone. The nanocoolants are prepared by mixing mineral oil with nanoparticles of Al2O3 (Aluminium Oxide), Al (Aluminium) and SWCNT (Single Walled Carbon Nanotube). The heat transfer performances of different nanocoolants are compared by varying the nanoparticle volume fraction (φ) and coolant velocity (Uc) in the range of 2% ≤ φ ≤ 8% and 1 m/s ≤ Uc ≤ 15 m/s, respectively. The results indicated a drastic drop in the cutting tool temperature with an increase in the volume fraction of dispersed nanoparticles and coolant velocity. The increase in volume fraction decreases the average cutting tool temperature by 25.65% and also enhances the average heat transfer rate by 25.43%. It is additionally observed that SWCNT nanocoolants exhibited a superior thermal performance and heat removal rate compared with Al and Al2O3 nanocoolants. The analysed numerical results are validated and are in good accordance with the benchmark results validated from literature.

Experimental and Numerical Study of Different Methods' Effects on Lubricant Flow on Temperatures and Strains of Turning Cutting Tool (HSS)

The aim of the present study is to facilitate the machining process of cast steel (HSS) through cooling and lubricating by compressed air with liquid in three directions and consisting of (oil, soap, carbolic acid, and sculpture) and was compared with the lubricant process in one direction and at different cutting speeds (2.08, 6.25, 10.4, and 14.16 m/sec). The Auto Desk Inventor programme is used to simulate the cutting process by applying cutting forces to the tool's shear surface. The interface equipment is used to measure cutting tool strains by the response of a strain gauge and the Arduino equipment to measure cutting tool temperature. In addition, the tool strain equations were used assuming that the cutting tool is fixed between the two walls (fixing region and surface of the workpiece) to get the best results at the same speed. The results refer to the lubricant in three directions, which is better than one direction due to decreasing cutting tool strain, reaction of cutting force on the shear surface of the cutting tool, and cutting tool temperature. The experimental results show that a cutting speed of 10.4 m/sec is the best for the cutting process. Furthermore, the numerical results are converged with practical results in a small correction factor (0.428), preventing the tool from vanishing.

Improving thermal conductivity of Inconel 718 through thermoelectric coupling to reduce cutting temperature

Inconel 718 is hard to machine with higher cutting temperature generated during machining process due to its low thermal conductivity. The thermal conductivity of materials consists of phonon and electronic thermal conductivity. The increase of electrical conductivity of material will improve its electronic thermal conductivity based on the Wiedemann–Franz law. A novel surface conductive active medium (SCAM) coating method is proposed. The SCAM is coated on the surface of Inconel 718 to be machined to decrease tool cutting temperature. The composition of electronic and phonon thermal conductivity of Inconel 718 is inspected by four-probe experiments. Two SCAMs including copper conductive adhesive (1.7 × 106 S m) and silver conductive adhesive (3.3 × 106 S m) are sampled in this research. The effect of SCAMs on improving the thermal conductivity of Inconel 718 is analyzed based on the serial electrical conductivity theoretical model. The maximum temperature of cutting tool during orthogonal cutting experiment decreases with the increase of SCAM electrical conductivity, which is agreed with the cutting temperature distribution predicted by theoretical calculations. It is demonstrated that the cutting tool temperatures can be reduced by improving thermal conductivity of Inconel 718 through coating surface conductive active mediums with high electrical conductivity.

Analysis of droplet characteristics and cooling lubrication effects in MQL milling of 316L stainless steel

The infiltration and cooling effect of lubricant droplets in the cutting zone largely depend on setting minimum quantity lubricant (MQL) system parameters appropriately. The study determines the optimal spray angle and spray distance relying on the geometric position relationship between the nozzle and the overall cutting zone. A numerical model that combines computational fluid dynamics (CFD) and discrete phase model (DPM) is presented to simulate droplet transport process for dynamic milling and one-tooth milling by flow field distribution and droplet characteristics. The influences of different spray distances and spray angles on the infiltration process and cutting tool temperature are analyzed. The experiments aimed at verifying the results of the analysis are conducted by measuring cutting force, cutting temperature, surface roughness, surface microtopography and tool wear. The result indicates that the spray distance has a significant impact on the jet divergence, and insufficient lubrication or excessive lubrication is effectively avoided with the optimal cutting distance. Spraying in the direction of cutting-out promotes the accessibility of the lubricant and greater concentration of droplets in the cutting zone, especially later in the cutting process, which results in increased infiltration, reduced friction, and improved heat dissipation. Moreover, experiments demonstate that the optimal state of jetting in the direction of cutting-out is 46 °C lower than that of dry cutting, the surface roughness is reduced by 19.8%, and the wear amount is reduced by roughly 34%. This study has a better understanding of the setting of spray distance and spray angle in MQL milling and the development of equipment, which provides theoretical guidance for the optimization of MQL system parameters in practical applications.

Estimating Machinability Factors in Turning of Inconel 625 under different lubricating conditions using 3D DEFORM FE Analysis

This paper contributes to the investigation of machinability factors in turning the nickel- based Inconel 625 superalloy with PVD coated TiAlN tungsten carbide cutting insert. The machinability parameters – cutting force (Fc), tool wear rate (𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑⁄), and tool temperature (T) are visualized graphically using the FE model based Deform 3D software interface. The paper discusses the application of boundary conditions, and meshing used for simulating results. The results of the dry turning simulation showed a maximum level of cutting force, tool-tip temperature, and tool wear rate in comparison with conventional MQL and NMQL conditions. The NMQL conditions showed a reduction in cutting force with the use of h-BN NMQL environment compared with dry and conventional MQL machining by 41% and 27%, respectively. Further, the comparison of cutting tool temperature for three simulated conditions showed a clear-cut reduction of temperature in NMQL conditions in comparison with dry and conventional MQL, by 44% and 30%, respectively.

Experimental investigation on machining characteristics of EN24 alloy steel using desirability approach

The metal cutting process has been signed an improved surface finishing of components to minimize the assembling difficulties. The machining was performed in EN24 alloy steel using carbide inserts. The Central Composite Design (CCD) of Response Surface Methodology (RSM) was followed to determine the number of cutting trials. Twenty cutting trials were carried out by varying cutting speed, feed rate and depth of cut. The experiment results were analyzed in Design Expert −11 software and the developed regression models verified the competence of each input variable on responses. This research identifies the optimized level of cutting parameters to obtain better results on the surface roughness (SR), cutting tool temperature (CTT) and metal remove rate (MRR). The multi responses were enhanced with aid of a single solution by using the desirability approach. Optimal cutting parameters were found at 1000 rpm, 0.1 mm and 0.75 mm speed, feed rate and depth of cut respectively. The input factor of speed reveals the most significant contribution on surface finish and cutting tool temperature, however, depth of cut implies a better contribution to metal removal rate. The validation trial results are agreed with the predicted values.

Analyze the Effect of Crater Cutting Tool Wear Modeling in the Machining of Aluminium Composite

The present investigation is used to analyze the effect of crater wear modeling in the machining of aluminium composite. Response surface methodology (RSM) is one of the best optimization technique used to bring out the optimal values of speed, feed and depth of cut for attain minimum surface roughness, cutting tool temperature and tool wear. AA7075 alloy with 15wt% of silicon carbide has been investigated in the dry machining condition. The double layered TiCN/Al2O3 coated tool was preferred. The worn surface analysis in coated tool was concentrated. The outcomes of the machining conditions were expected to improve surface finish. Novel approach of this investigation is to analyze the surface morphology to visualize the surface peak and valley profile of the coated tool and analyzed with various surface parameters that decide the surface roughness of the profile.

Micro-texture dependent temperature distribution of CVD diamond thick film cutting tools during turning of Ti-6Al-4V

Machining titanium alloys such as Ti-6Al-4V results in a high thermomechanical load on cutting tools and consequently short tool lifes. With respect to a necessary reduction of the resulting cutting tool temperatures, ultrashort pulse (USP) laser fabricated micro-textured rake faces offer direct supply of cooling lubricant into the cutting zone and lead to a reduced heat induction. As a result, micro-textured CVD diamond thick film cutting tools are also capable of machining high-performance materials due to reduced contact temperatures. In the scope of the research, the resulting temperature distribution for micro-textured rake faces will be compared under both dry and wet process conditions. Measurements show a reduction of the resulting cutting tool temperatures of Δϑt = 27.9 % using micro-textured cutting tools compared to non-textured cutting tools. A validated simulation provides valuable information about the contact temperatures enabling a specific development of the micro-texture geometry. As a result, a reduction of the contact temperature between chip and rake face by ΔϑT = 24.7 % was possible.

Performance evaluation of graphene added nanofluids and self-lubricating tools in machining Inconel 718

PurposeInconel 718 is difficult to machine due to its high toughness and study hardenability. Though the use of cutting fluids alleviates the problem, it is not sustainable. So, supply of a small quantity of specialized coolant to the machining zone or use of a solid lubricant is a possible solution. The purpose of the present work is to improve machinability of Inconel718 using graphene nanoplatelets.Design/methodology/approachIn the present study, graphene is used in the machining of Inconel 718 alloy. Graphene is applied in the following two forms: as a solid lubricant and as an inclusion in cutting fluid. Graphene-based self-lubricating tool and graphene added nanofluids are prepared and applied to turning of Inconel 718 at varying cutting velocities. Performances are compared by measuring cutting forces, cutting temperature, tool wear and surface roughness.FindingsGraphene, in both forms, showed superior performance compared to dry machining. In total, 0.3 Wt.% graphene added nanofluids showed the lowest cutting tool temperature and flank wear with 44.95% and 83.37% decrease, respectively, compared to dry machining and lowest surface roughness, 0.424 times compared to dry machining at 87 m/min.Originality/valueGraphene could improve the machinability of Inconel 718 when used in tools as a solid lubricant and also when used as a dispersant in cutting fluid. Graphene used as a dispersant in cutting fluid is found to be more effective.

Three-dimensional transient cutting tool temperature field model based on periodic heat transfer for high-speed milling of compacted graphite iron

The new material, compacted graphite iron, plays a key role in the reliability of engine and the realization of high emission standard, but it is a difficult-to-machine material. In high-speed milling process of compacted graphite iron, thermal crack induced by thermal stress is the main reason for tool breakage and chipping. In order to reveal the initiation and propagation mechanisms of thermal cracks, and improve tool life by controlling the formation of thermal crack, it is necessary to study the three-dimensional transient cutting tool temperature field under the condition of periodic heat transfer in intermittent cutting. In this paper, the three-dimensional transient FEM cutting tool temperature field model for high-speed milling of compacted graphite iron was established by using the heat source method. The uneven spatial distribution of the heat flux on the rake face of the tool, and the changes of heat flux density due to the transient cutting thickness and tool-chip contact length over time were considered, and the influence of boundary conditions in the cutting stage and the non-cutting stage were also all taken into account. The heat flux action time and the ratio of cutting time and non-cutting time in the model were set according to the experimental conditions of actual milling process. The established three-dimensional transient cutting tool temperature field model was finally verified by measuring the real temperature in high-speed orthogonal turning experiment. The results showed that the predicted value of the model was consistent with the experimental value, and the predicted error was less than 6.0%, indicating that the model has high accuracy for simulation. This model has great theoretical significance for the development of new tool materials for compacted graphite iron processing, studying the mechanism of thermal crack, controlling and preventing tool failure caused by thermal crack.

Analytical Modeling of Shear Localization in Orthogonal Cutting Processes

AbstractThis paper presents an analytical thermo-mechanical model of shear localization and shear band formation in orthogonal cutting of high-strength metallic alloys. The deformation process of the workpiece material includes three stages: homogeneous deformation, shear localization, and chip segmentation. A boundary layer analysis is used to analytically predict the temperature, stress, and strain rate variations in the primary shear zone associated with the shear localization. The predictions of shear band spacing and width from the proposed model are verified by experimental characterization of the chip morphology. The rolling of shear bands on the tool rake face is discussed from the experimental observations. The cutting tool temperature, which is influenced by the heat generated during the shear band formation, is simulated and compared with finite element simulations. The proposed analytical model reveals the fundamental mechanism of the complete shear localization process in orthogonal cutting and predicts the stress and temperature variations with high computational efficiency.

Analytical prediction of cutting tool temperature distribution in orthogonal cutting including third deformation zone

The present study introduces a novel model for the prediction of temperature in a cutting tool while the effects of all three deformation zones are considered. The model considers the effect of cutting-edge radius and the third deformation zone for the first time in the literature in terms of temperature prediction using thermo-mechanical approach with dual-zone friction model. The material behavior is defined by the Johnson-Cook constitutive model. For the calculation of heat flux on the rake and flank faces, a dual-zone model was used. The temperature distributions at the tool-chip and tool-workpiece boundaries were determined analytically, and the temperature distribution inside the tool was calculated using the Finite Difference Method. In order to verify the model, experiments were performed with AISI1050 steel and Al7075 workpiece materials using tungsten-carbide cutting tools. A good agreement is observed between the model predictions and the test results. This study also examined the effects of cutting-edge geometry and cutting conditions on cutting temperature, which can be used in optimized selection of cutting parameters and tool geometry.

Influence of machining conditions on tool wear and surface characteristics in hot turning of AISI630 steel

Hot machining as one of the clean production techniques is used to improve the machinability of hard-to-cut materials. In this technique, an external heat source is used to soften the workpiece material and improves its machinability and sustainability by reducing the machining forces and eliminating cutting fluid application. In the present work, the conventional and hot turning of precipitation-hardened AISI630 stainless steel was evaluated in both numerical and experimental methods. Turning experiments were carried out using PVD-(Ti, Al)N/(Al, Cr)2O3-coated carbide tools, and the flank wear was measured by using scanning electron microscopy (SEM). Numerical analysis was carried out by finite elements method (FEM) to calculate the cutting tool temperature, cutting force values, and cutting force fluctuation. The numerical results showed that the hot turning not only decreases the cutting force but also decreases the amplitude of cutting force fluctuations up to 47%. The experimental results showed that hot turning at 300 °C reduces the tool’s flank wear and machined surface roughness up to 33% and 23%, respectively. Therefore, hot machining could be one of the realistic alternatives that can rise the machining processes on a sustainable level.

Minimum Quantity Lubrication-Alternative to Flood Cutting and Dry Cutting

For any machining process cutting tool temperature, surface roughness value of work piece, cutting forces are the performance deciding parameters. These parameters directly, indirectly affect the tool life and thus affect machine cycle time, product cost and productivity. Cutting fluids are used to improve the machining performance however its cost and environment unfriendliness raise several questions. Researchers have documented several adverse health and environment effects of cutting fluids through their work. Plenty are efforts are going on to reduce the cutting fluid costs and to minimize its harmful effect to the environment. There is urgent need to provide sustainable, low cost and productive alternative to conventional machining processes. Minimum quantity lubrication is emerging as a tool to minimize the quantity exposure to the cutting fluids. In present work, low cost minimum quantity lubrication is used to verify its performance in terms of temperature, cutting forces and surface roughness. Results are compared for dry, flood and MQL cutting. Performance of MQL is better as compared to dry and flood cutting.