Tool Temperature Distribution Research Articles

Effect of cutting fluid supply conditions on tool loads during continuous and interrupted orthogonal cutting

AbstractIn metalworking, cutting fluids play an important role by reducing heat and friction during machining, extending tool life, and improving surface finish. Although the positive effects of cutting fluid have been confirmed in many studies, the relevant cutting fluid parameters such as nozzle cross-section area and supply pressure, as well as their influence on the thermo-mechanical loads of the cutting tool, have been insufficiently investigated. This study investigates the effects of cutting fluid supply conditions on tool loads during continuous and interrupted orthogonal cutting processes. The research specifically addresses the impact of nozzle geometry and fluid jet orientation on the thermo-mechanical loads on the cutting tool, which have been underexplored in previous studies. A prototype tool holder, designed and additively manufactured for this purpose, allows for variations in nozzle geometry and jet orientation. Experiments were conducted under varying cutting parameters, nozzle geometries, and fluid pressures, with tool temperature being monitored through an embedded thermocouple. The results show that nozzle geometry significantly affects chip shape, which directly affects cooling efficiency and, consequently, tool temperature. The study also uses an inversely calibrated analytical model to analyze the tool temperature distribution, which shows that the highest temperatures occur in the tool-chip contact area, while temperatures outside this area decrease rapidly. In addition, the percentage of heat conducted into the tool decreases with increasing Péclet number, which is consistent in both continuous and interrupted cutting scenarios. These findings provide a deeper understanding of how cutting fluid nozzle design affects tool performance and establish a foundation for model-based temperature analysis in machining processes.

Multi-point thermometry tool and in-situ measurement of temperature fields

In-situ real-time measurement of instantaneous milling temperature distribution is a key issue to realize efficient machining. For the foregoing reasons, the milling model of Inconel 718 was established, and the cloud diagram of tool temperature distribution during milling was obtained. A multi-point temperature measurement tool for milling temperature with an integrated thin-film temperature sensor was designed. The real-time temperature distribution of the tool during milling was obtained from 27 sets of milling tests. The impact of each milling parameter on the milling temperature was analyzed by ANOVA.

A simulation-based analysis on the cooling effect and the tool temperature distribution in modulated turning (MT)

Modulation assistance is widely used for breaking chips of highly ductile materials in turning. This process is also known as the “modulated turning” (MT) or the “modulation assisted machining (MAM)”. The process transforms continuous single point turning into an intermittent cutting process where the tool tip briefly disengages from the workpiece generating discrete short chips. Resembling the milling process mechanics, periodic tool disengagements in modulated turning introduces cyclic cool-down periods and thus it can potentially attenuate tool-tip temperatures. It has been hypothesized that this effect can greatly lower maximum and the average tool-tip temperatures improving wear resistance of the process. This paper presents a thermal model to predict the tool-tip temperature distribution in modulated turning. A generalized chip formation formulation is first developed to predict the uncut chip thickness variation, cutting forces and the tool engagement/disengagement phase durations. Thermomechanical behavior of tool-chip contact is then modeled to predict the rake face temperature distribution. Simulation studies are presented to analyze the temperature distribution and understand peak temperature (hot) spots on the rake face. It has shown that the phase angle parameter – the frequency ratio between workpiece rotation and tool modulation– of MT plays a key role in controlling the hot spots on the rake and can be used as a tool to influence the wear regime.

3D finite element simulation for tool temperature distribution and chip formation during drilling of Ti6Al4V alloy

A comprehensive 3D finite element simulation study has been conducted to investigate the tool temperature distribution along cutting edge and chip formation during drilling of Ti6Al4V alloy by using commercial finite element software Abaqus/Explicit. The Johnson–Cook material constitutive model and material failure criterion were implemented across the formulations to achieve the tool temperature and chip formation in the drilling process. The effect of different mesh sizes on simulation results was also analyzed. To assess and verify the accuracy of the simulation model, the corresponding experiment studies were carried out by measuring the thrust force, tool temperature, and chip morphology. Compared results show that the predicted thrust force, temperature distribution, and chip morphology are in good agreement with those tested from experiments. According to the combination of both simulations and experiments, it can be not only found the whole varying pattern of the thrust force but also reveal that the temperature decreases from drill center to outer corner along the primary cutting edge. In addition, it can provide a more detailed and profound knowledge about chip formation. All these are assumed to be recommendations for the optimization of tool geometry and drilling processing.

Temperature and strain distribution during friction stir welding of AA6061 and AA5052 aluminum alloy using deform 3D

This study investigated the effect of heat generation during friction stir welding (FSW) on dissimilar aluminium alloy plates AA6061 and AA5052 using process variables such as tool rotational speed, feed rate and temperature distribution. Temperature distributions on the workpiece were recorded at advancing side and receding side during welding by using thermocouples and revealed that temperatures on the advancing side are greater than those on the receding side. The FSW process was simulated at the tool speed of 1000, 1200 and 1400 rpm, feed rate of 20, 40, 60 mm/min. A Taguchi OA has been used for designed the experiments. The findings of the micro hardness test at the welded zone analysed using Vickers’s tester. Microstructure analysis of AA6061 identical welds reveals that grains are slightly reduced at HAZ, while analysis of AA5052 and AA6061 dissimilar welds reveals that grain are significantly enlarged at weldment than base metal. It also found that, the tool speed increases while maintaining a steady feed rate, increased the amount of heat generated in weld zones. On the other hand, increasing feed rate while maintaining constant tool rotational speeds results in a decrease in the amount of heat created in weld zones. Analysis of variance (ANOVA) revealed, the optimal condition of temperature distribution and heat generation is T3F1 (i.e., tool speed of 1400 rpm and feed rate of 20 mm/min). A model of the workpiece and tool was developed using Deform-3D Software for friction stir welding, and thermal analysis was performed to analyse the temperature distribution.

Numerical investigations on the optimal tool temperature distribution for the integrated manufacturing of hybrid structures

The combination of hot-stamped steels and fibre-reinforced thermoplastics (FRTP) offers great potential for lightweight design. The process steps of hot stamping and thermoforming for the manufacturing of such hybrid structures are usually carried out in two separate steps. After hot stamping, the blank has to be reheated for the application of FRTP in order to enable the bonding of FRTP to the blank. Process integration of the individual processes means that reheating of the blank during thermoforming is no longer necessary. Due to non-uniform contact conditions during hot stamping between blank and tool, an inhomogeneous temperature distribution in the blank occurs, which would lead to non-uniform bonding properties between blank and FRTP after thermoforming. The aim of this work is to determine this non-uniform contact and the resulting heat transfer by a numerical model. By segmenting the tool in the model, a possibility is shown to control the non-uniform contact and to achieve a homogeneous temperature distribution in the blank after hot stamping. Furthermore, the temperature adaptability of the used tool and the resulting temperature distribution in the blank is investigated. Finally, the manufactured structures are tested in a numerical three-point bending test in order to be able to make a statement about their performances.

A Novel Fluid–Structure Interaction (FSI) Modeling Approach to Predict the Temperature Distribution in Single-Point Cutting Tool for Condition Monitoring During Turning Process

A Novel Fluid–Structure Interaction (FSI) Modeling Approach to Predict the Temperature Distribution in Single-Point Cutting Tool for Condition Monitoring During Turning Process

Analytical thermal model of orthogonal cutting process for predicting the temperature of the cutting tool with temperature-dependent thermal conductivity

High temperatures generated in cutting processes significantly affect the surface integrity of machined parts and tool wear, leading to workpiece thermal damage, tensile residual stresses in the workpiece and a reduction in tool life. In recent years, different analytical thermal models to predict cutting temperatures have been developed in literature based on 2D modeling of the cutting process and the assumption that thermal conductivities of workpiece and chip are not dependent on temperature. However, this dependence of conductivity on temperature may have a significant influence on predicted temperatures and must be taken into account. In this paper, a thermal model of the orthogonal cutting process that considers thermal conductivity of materials (chip and tool) to be dependent on temperature is developed. A linear variation of thermal conductivity with temperature is assumed for chip (workpiece) and tool materials. The model is based on application of: (1) the Kirchhoff transformation in order to convert the nonlinear heat conduction problem into a linear one, (2) the theory of moving and stationary heat sources in semi-infinite and infinite mediums in order to model primary and secondary deformation zones and (3) imaginary heat sources to meet adiabatic boundary conditions in the chip and tool. Imaginary heat sources were defined in the thermal model proposed in this paper in such a way that the effect of the tool-chip interface dimensions and of cutting tool width on the tool temperature could be taken into account. This allows the temperature on the rake face and lateral faces of the tool to be predicted. To this end, a new methodology that considers the temperature-dependent thermal conductivity of materials was developed in order to estimate heat partition ratio along the secondary heat source (tool-chip interface), which is assumed to be non-uniform. Orthogonal cutting tests were also performed in order to verify model predictions by comparing them to tool temperature distributions measured using an IR camera.

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.

Analysis of turbulent two-phase flow and heat transfer using nanofluid

Finite element analysis of turbulent two-phase flow and heat transfer was conducted in the present investigation to analyze the effect of adding Al2O3 nanoparticles to the minimum quantity lubrication (MQL) cooling fluid on the cutting tool temperature distribution. Discrete phase model (DPM) was used to describe the trajectory of the mist in the fluid domain. The numerical results presented in this investigation were in good correlation with the experimental results. The findings of this investigation demonstrated that the average temperature of the cutting tool was found to decrease with adding Al2O3 nanoparticles. Further, the results demonstrated that the temperature variation was significant in the vicinity of the tool tip compared to a faraway point. The compressed air pressure was found to have a profound effect on the temperature of the cutting tool. This study was an effort to determine the performance of the cutting tool using MQL based nanofluid and utilizing discrete phase model.

Thermal analysis of pentagonal profiled friction stir welding tool using Ansys

In friction stir welding process heat generation in the welding zone is most common due to the friction in between the tool and the weldment. When the heat concentration in the weld zone, then the flow of heat through the tool as well as in the weldment. It is requisite to dissipate the heat in order to weld continuously and to increase the weld distance. It is up to the tool design and tool profiles. By doing the thermal simulation in the tool, the tool temperature distribution and compare the number of tools with respect to temperature and able to finalize the tool which has maximum heat dissipation. In this work, 3 tools are designed in total with a pentagon pin profile with different volumes. Which is modeled in solid works software and converted into the Ansys file, then the material properties to be selected, each tool has different materials. Then it gives the corresponding mesh size and boundary conditions such as Temperature, Convection, etc. The tool has been mesh and found out the solution for all tools. As a result, it is found that tool number 1 has a maximum heat dissipation.

RETRACTED: Evaluation of tool temperature distribution in MQL drilling of aluminum 2024-T351

Minimum quantity lubrication (MQL) as a green technology is widely employed in metal removal manufacturing, which can achieve lower cutting temperature and higher machining efficiency environmentally. However, how to evaluate the tool temperature distribution in drilling process with MQL is still significantly lacking. For this purpose, a tool-foil thermocouple system was developed and the influence of cooling conditions and cutting variations on tool temperature has been experimentally analyzed during high-throughput drilling of aluminum alloy AA2024 in current study. Results indicate that the maximum temperature along cutting edge is observed near drill center due to heat accumulation. Using MQL can decrease the temperature difference between drill center and outer corner compared with dry and air cooling conditions. Temperature distribution profiles are more sensitive to feed rate than cutting speed. Increasing feed rate can result in a great increasing of average temperature. Chipping is only observed on the peripheral corner under MQL condition, while adhesion and built up edge (BUE) almost extend across the whole cutting edge under dry drilling due to the absence of lubrication and coolant.

Simulation of thermo-mechanical behaviour of friction drilling process

Friction drilling is a novel technique for producing holes in thin sheet metal without plastic shear and material removal. In this process, no chip comes out, the displaced material in the region of hole thus made, forms a bushing by a conical friction drilling tool. During the process of producing holes in the sheet metal, severe plastic deformation of workpiece material occurs and eventually, the temperature distribution in tool and workpiece is very high. Hence, simulation of the process is necessary to predict the direction of material flow and high temperature distribution which are challenging to measure by experimentation alone. The objective of this work is to numerically analyse the pattern of bush formation in thin sheet metal of galvanised steel during the process and to predict the temperature distribution, axial force, and torque in the work piece. Validation shows high degree of agreement between the numerical results and experimental results.

Temperature Field Measurement in a Cutting Tool by Laser Interferometry

To increase machining efficiency, in addition to determining the temperature distribution on the tool surface, it is also necessary to determine the internal temperature distribution. The existing methods for determining the cutting tool temperature distribution and temperature field measurement have significant disadvantages, which limit their applicability and accuracy. The purpose of this study is to develop and test a novel cutting tool temperature field measurement method. The method involves recording the cutting tool thermal expansion fields by laser interferometry and calculating the tool material temperatures with its coefficient of thermal expansion (CTE). Compared with the methods employing infrared thermometry, the method developed in the present study has a higher spatial resolution and a lower achievable field of view due to its usage of light in the visible region. In addition, since the oxidation film has a higher reflection coefficient for visible light, the present method is less sensitive to the thin-film interference on an oxidized tool surface than those using infrared thermometry, eliminating the false shift of the measured temperature. Moreover, by utilizing cheaper optical components and equipment for interference fringe pattern registration, this method is more affordable. Unlike the emissivity coefficient in infrared thermometry, CTE is independent of changes in the surface quality and can be measured with high accuracy by modern dilatometry. Therefore, the developed method, which employs CTE to calculate the temperature, has a higher reliability. In the present study, the efficiency of this method is tested by the orthogonal turning of difficult-to-cut martensitic heat-treated steel with a cemented tungsten carbide tool. Through the experiment, the temperature distributions along the rake face and flank of the tool, as well as the temperature field inside the tool, were obtained. The results can improve the temperature field measurement in machining cutting tools.

A Coupling Approach Combining Computational Fluid Dynamics and Finite Element Method to Predict Cutting Fluid Effects on the Tool Temperature in Cutting Processes

In metal cutting processes, the use of cutting fluids shows significant effects on workpiece surface quality by reducing thermomechanical loads on cutting tool and workpiece. Many efforts are made to model these thermomechanical processes, however without considering detailed heat transfer between cutting fluid, tool, and workpiece. To account for heat transfer effects, a coupling approach is developed, which combines computational fluid dynamics (CFD) and finite element method (FEM) chip formation simulation. Prior to the simulation, experimental investigations in orthogonal cutting in dry and wet cutting conditions with two different workpiece materials (AISI 1045 and DA 718) are conducted. To measure the tool temperature in dry as well as in wet cutting conditions, a two color pyrometer is placed inside an electrical discharge machining (EDM) drilled cutting tool hole. Besides tool temperature, the cutting force is recorded during the experiments and later used to calculate heat source terms for the CFD simulation. After the experiments, FEM chip formation simulations are performed and provide the chip forms for the CFD mesh generation. In general, CFD simulation and experiment are in reasonable agreement, as for each workpiece setup the measured temperature data are located between the simulation results from the two different tool geometries. Furthermore, numerical and experimental results both show a decrease of tool temperature in wet cutting conditions, however revealing a more significant cooling effect in a AISI 1045 workpiece setup. The results suggest that the placement of drilling holes has a major influence on the local tool temperature distribution, as the drilling hole equals a thermal resistance and hence leads to elevated temperatures at the tool front.

Thermal characteristics testing and thermal error modeling on a worm gear grinding machine considering cutting fluid thermal effect

The coolant absorbing cutting heat has strong influence on thermal behaviors for high precision machine tool using flood cooling technique. However, the majority of applied thermal error compensation models are without considering cutting fluid thermal effect, which results in poor simulation accuracy of thermal deformation. This paper experimentally investigated the effect of coolant temperature on the thermal characteristics of a worm gear precision grinding machine. Experiments were carried out under three conditions: no-load with coolant, no-load with heated coolant, and load test. Moreover, a real-time thermal error compensation model was theoretically developed and validated based on the experimental data involving the cutting fluid thermal effect. The results show that the temperature distribution of the machine tool was more uniform and the temperature gradient was decreased when the grinding heat was partially considered using heated coolant, which indicates that coolant can positively affect the thermal behavior if it is controlled to flow correctly. The thermal error compensation model was built based on the optimal four temperature variables and with a high accurate prediction and robustness. For the no-load operating conditions, the maximum absolute errors and mean absolute errors are 2.7 μm and 1.5 μm respectively. For the load operating conditions, the prediction accuracy of the model built by no-load measuring data is also greatly improved because the grinding heat is partially considered by heated coolant in the no-load test. And the maximum prediction error is 13.0% when the influence of the feed drive system adjustment is considered.

Simulation of Material Removal Process in EDM with Composite Tools

With the development of (electrical discharge machining) EDM technology, composite tools with special features gradually replace the traditional single-material tools and have become widely used in specific processing conditions. In order to predict the wear of composite tool effectively, in this paper, a material removal model of single-pulse EDM with composite tools was established by using the finite element method. The surface temperature distribution of the composite tool was obtained by taking the copper-die steel tool as the analysis object. And the shape of discharge crater as well as the removal volume was obtained by the element birth and death method. The influences of discharge parameters and tool materials on the removal volume were analyzed respectively. The EDM experiments were carried out by using copper-die steel as the composite tool to verify the simulation results. It shows that the errors between actual machining results and the simulation results are less than 10%, which proves the accuracy of the simulation model.

Thermal Modeling of Tool Temperature Distribution during High Pressure Coolant Assisted Turning of Inconel 718.

This paper presents a finite-element modeling (FEM) of tool temperature distribution during high pressure coolant assisted turning of Inconel 718, which belongs to the heat resistance superalloys of the Nickel-Chromium family. Machining trials were conducted under four machining conditions: dry, conventional wet machining, high pressure coolant at 50 bar, and high pressure coolant at 80 bar. Temperature during machining plays a very important role in the overall performance of machining processes. Since in the current investigation a high pressure coolant jet was supplied in the cutting zone between tool and work material, it was a very difficult task to measure the tool temperature correctly. Thus, FEM was used as a modeling tool to predict tool temperature. The results of the modeling showed that the temperature was considerably influenced by coolant pressure: the high pressure jet was able to penetrate into the interface between tool and work material, thus providing both an efficient cooling and effective lubricating action.

Comparative study of energy efficiency and environmental impact in magnetic field assisted and conventional electrical discharge machining

Electrical discharge machining is a significant non-traditional technique, widely used in the precise manufacturing field. However, the electrical discharge machining process possesses plenty of energy consumption and hazardous exhaust emissions. Since a sustainable machining technique, external magnetic field assisted, could dramatically develop sustainable machining performance of electrical discharge machining process, this paper presents a comparative study energy efficiency and environmental impact in magnetic field assisted electrical discharge machining and conventional electrical discharge machining. A novel thermo-physical model was proposed to calculate energy distribution under the single/continuous discharge, which was verified by a series of corresponding experiments. Then, based on simulation and experimental methods, a comparative study on the magnetic field assisted electrical discharge machining and conventional electrical discharge machining was conducted to analyze the discharge energy flowing and temperature distribution of workpiece, electrode tool and debris. Moreover, the effects of external magnetic field on the machining performance, environmental impacts and energy efficiency were presented. Eventually, it can be found out that the effect of magnetic field contributes to increasing energy utilization efficiency by 15.2%, material erosion efficiency by 22.6%, and material removal rate by 21.9%. To balance energy efficiency and surface roughness (Ra), the optimal parameter combination is obtained as below: magnetic field intensity: 0.2T, discharge current: 7–9A, and pulse duration: 300s.

Impact of Flow Conditions in Cooling Channels on Thermal Cycling

In order to improve the set-up of industrial press hardening processes, companies and researchers are spending considerable efforts in the design and positioning of cooling channels. Following the increasing demands for modelling options, FEA software vendors have implemented corresponding features in their codes. Modeling cooling channels in FEA simulation facilitates a more accurate prediction of the location and dimensions of hot spots on the tool surface.The present simulation case study is based on a complete tool set up for a typical part. The FE-model of tool set-up, including a suitable cooling channel design, has been utilized for a study on press hardening of 22MnB5. The effectiveness of cooling channel design is determined by the flow conditions of the cooling media - here water. The flow rate and cooling media temperatures are the parameters with most influence on the thermal behavior of the tool. The impact of variations in these parameters on the final surface temperature distribution on tools, and the ramp-up of this distribution to thermal steady state, are the subject of this study. Beyond tool temperature distribution, the impact of the above parameters on the quality of produced parts is assessed by evaluating typical part quality metrics: hardness, martensite volume fraction in the part’s microstructure, and thermal distortion.It is observed that due to the complexity of the press hardening process, the details of cooling channel flow conditions do not carry a direct and proportional impact on part quality outcomes. This observation clearly indicates that engineers can derive descriptions of the cooling channel flow conditions from easy-to-use analysis tools that are fully integrated with the simulation of the forming process, rather than resort to extended, time consuming “offline” flow computations. An analytical method for calculation of cooling channel flow conditions is also introduced by the authors.