Temperature Field Of Workpiece Research Articles

Modelling and simulation of heat flow in indexable insert drilling

In machining, the heat generated during the process deforms the components and the final shape might not meet specified tolerances. There is therefore a need for a compensation strategy which requires knowledge of the workpiece temperature field and the associated thermal distortions. In this work, a methodology is presented for the determination of the heat load for indexable insert drilling of AISI 4140. Compared to previous research, this work has introduced a varying heat load. The heat load is extracted from thermo-mechanical finite element simulations for different nominal chip thicknesses and cutting speeds using the coupled Eulerian-Lagrangian formulation of an orthogonal turning process. The heat load is then transferred to a simplified 2D axisymmetric heat transfer model where the in-process temperature field in the workpiece is predicted. To verify the methodology, the predicted temperatures are compared to the experimentally measured temperatures for various feed rates. It is found that the model is capable of predicting the workpiece temperatures reasonably well. However, the methodology needs to be further explored to validate its applicability.

Multi-Zone Integrated Iterative-Decoupling Control of Temperature Field of Large-Scale Vertical Quenching Furnaces Based on ESRNN

Temperature uniformity within a large vertical quenching furnace is the key factor to determine the properties of aluminum workpieces. The existing temperature control method for quenching furnaces cannot overcome the influence of multi-zone coupling issues, which lead to unstable product performance and a lack of key performance. Based on a workpiece temperature field model, a spatial-temporal dimensional extrapolation method is proposed to realize fast and accurate solving of the temperature model. In view of the over-burning and under-burning problems during the temperature rising period, a self-incentive nonparametric adaptive iterative control algorithm is presented, which realizes consistent temperature rising of multiple heating zones. Aiming at the strong coupling problem of the multi-zone heating manner during the temperature holding period, the decoupling problem of multiple control loops is converted into a multi-loop integrated control optimization problem. An eigenvector self-update recurrent neural network (ESRNN) is constructed to determine the Jacobian information and tune the control parameters of each loop controller in real time, thereby realizing the integrated intelligent decoupling control of multiple heating loops. Simulation and industrial results verify the superiority of the proposed method, which can realize high-precision and high-uniformity control of a large-scale temperature field and effectively improve the quality and performance of aluminum alloy workpieces.

Numerical simulation of workpiece temperature field during radial shear rolling of biomedical Co-Cr-Mo alloy

This paper describes the analysis of temperature field of workpiece during radial shear rolling (RSR) of biomedical Co-28Cr-6Mo alloy. In the process of hot metal forming, the temperature distribution in the deformation zone has a significant influence on the quality and properties of the final product. In some cases, the deformation within a narrow temperature range is required to provide the desired properties. To obtain data on change in temperature, the computer simulation of RSR was carried out using finite element method. According to simulation results, the temperature distribution of bar depending on the variable process parameters such as temperature of workpiece, rotary velocity of rolls, elongation ratio, diameter of workpiece, and temperature of tool was evaluated. It was determined that the most significant parameters influencing on the distribution of the temperature field are the workpiece heating temperature and the rolling speed. The RSR process makes it possible to effectively manage the distribution of temperature field due to selecting technological parameters and, thereby, control the formation of the alloy structure. The data obtained can be useful for developing the modes of RSR of Co–Cr–Mo alloy.

Laser scribing of fluorine-doped tin oxide coated on glass substrate in air and water

Fluorine-doped tin oxide (FTO) is one of the conductive layers used in the emerging perovskite solar cell technology, and the layer is typically scribed by a laser beam. However, thermal damage induced by laser deteriorates the scribe quality and in turn reduces the efficiency of the solar panel. This paper compares five different laser scribing techniques for isolating the FTO on the film and substrate sides both in air and water environments. The width and depth of laser-scribed channels, as well as burrs height, produced by using the different techniques were examined and compared. A clean and consistent scribe with negligible burrs was achievable by ablating the FTO film in the flowing water layer. Using this technique, its burr height index was found to reduce by 62.5% compared to the laser scribing of FTO film in air. A three-dimensional transient heat transfer model was also developed in this study to simulate the temperature field of workpiece subjected to the laser scribing in air and in flowing water environments. The thermal damage region was substantially small when the ablation was performed in the flowing water film. This could be a promising technique for the P1 scribing step in the manufacturing of emerging perovskite solar modules.

Modeling of plasma temperature distribution during micro-EDM for silicon single crystal

In silicon single crystal micro-electrical discharge machining (Micro-EDM), the plasma channel and workpiece temperature field directly affect the machined parts. For Si single crystal, with short single discharge time and small inter-electrode gap, the temperature cannot be easily measured directly. Based on the theory of energy conservation and heat conduction, combined with Micro-EDM process, in this paper, thermodynamic analysis of plasma in Micro-EDM process is conducted, and a plasma temperature distribution model considering latent heat of fusion is established. Adopting Gaussian distribution heat flux boundary condition and the temperature field distribution of the workpiece surface is simulated by FLUENT. The relationship between material removal rate (MRR) and surface roughness (SR) corresponding to temperature distribution under different peak current and pulse width conditions is analyzed. The results show that plasma temperature has a positive correlation with peak current and pulse width. The increase of peak current and pulse width within the processing parameter range leads to the increase of MRR and SR. The experimental results verify the correctness of the model.

Analytical modeling of machining-induced residual stresses in milling of complex surface

The distribution of residual stresses has a significant effect on fatigue life in milling process. In previous works, the predicted model of residual stresses was focusing on orthogonal cutting, while milling residual stresses is seldom reported. An analytical model for the generation of residual stresses induced by complex surface milling is proposed. Estimates of the mechanical stresses induced by the milling process have been determined through contact mechanics and the geometric transformations within the part. The temperature field of workpiece induced by milling is predicted by analytical model. Estimates of the residual stresses were obtained using an elastic-plastic model and a relaxation procedure. The proposed model is validated with milling experiments. This work can be further applied to improve surface integrity of workpieces by machining parameters optimization.

Estimation of residual stresses in gear form grinding using finite element analysis and experimental study based on grinding force and heat flux distribution models

Form grinding is one of the most important finishing methods to produce precision gears with high surface quality; however, the generation of high temperatures in the ground zone due to very high energy density induces a complex residual stress field during this process. In the present research, temperature distributions in the workpiece were examined using the finite element method (FEM). The heat generation process was assumed as a three-dimensional distribution of moving heat flux, and different grinding factors, including nonlinear distribution of tangential grinding force, grinding parameters, heat partition ratio along the tooth profile, and triangularly distributed heat source along the contact arc, were considered for thermal analysis. The workpiece temperature field was used as thermal loading in stress calculations, and thermal stresses were determined by thermal elastic–plastic FEM with temperature-dependent material properties and a bilinear kinematic hardening model. Further, grinding forces along the tooth profile were measured using a force dynamometer; surface temperatures were estimated by thermocouples pre-embedded along tooth profile; and surface residual stresses in both grinding direction and tooth profile direction were measured by X-ray diffraction (XRD) analysis. Experimental results of temperatures and residual stresses were utilized to validate the FEM results, and the comparison between numerical and experimental results suggests that the proposed model can be adopted to estimate residual stresses in gear form grinding.

Simulation on Temperature Field of Friction Stir Welding of 2A14 Aluminum Alloy Based on Equivalent Film Method

Backing plate has an important influence on the temperature field of workpiece during the friction stir welding process. In order to predict the temperature field of workpiece accurately, a thermal-fluid coupled friction stir welding calculation model including workpiece and backing plate was developed. In the model, an equivalent film method was proposed to simplify the contact heat transfer between workpiece and backing plate to a heat conduction problem. The computational fluid dynamic software FLUENT was ultilized to simulate the friction stir welding process of 2A14 aluminum alloy. As a result, the steady-state temperature field during the friction stir welding process was predicted and analyzed. The welding process test was carried out to verify the simulation results of temperature field. The compared results show that the simulated temperature and the measured values of all measuring points are in good agreement. Using the simulation method proposed in this paper, the calculation accuracy of temperature field during the friction stir welding process could be relatively high and the maximum error is 4.61%. In addition, there is a good corresponding relationship between the temperature distribution and the various regions of weld cross section.

Multi-zone multi-phase temperature field modelling of aluminum alloy workpieces in large-scale vertical quench furnaces

Fast and accurate acquisition of the temperature information of a workpiece is essential to achieve temperature uniformity control in the quenching process. Based on the special quenching technique, a three-dimensional multi-zone multi-phase thermal model of aluminum alloy workpieces has been developed. The boundary conditions of the developed model are determined according to the multi-phase heating feature. Considering the detailed furnace geometric parameters and the multi-zone heating manner, the radiative heat flux is calculated by a simplified zone method. To satisfy the desired computational precision, a novel double-extrapolation finite element method (EFEM), which has high accuracy and time efficiency, is proposed to solve the transient temperature field of the workpiece. The efficiency of the mathematical model is validated by a comparison with experimental data obtained from a measurement campaign with a test workpiece. Compared with the finite element method (FEM), the simulation results show that the presented EFEM is accurate enough for engineering purposes. The application results demonstrate that the developed model provides a reliable workpiece temperature field and is helpful for temperature uniformity control of large-scale vertical quench furnaces.

Experimental Investigation and 3D Finite Element Prediction of Temperature Distribution during Travelling Heat Sourced from Oxyacetylene Flame

This paper presents a 3D transient finite element modelling of the workpiece temperature field produced during the travelling heat sourced from oxyacetylene flame. The proposed model was given in terms of preheat-only test applicable during thermally enhanced machining using the oxyacetylene flame as a heat source. The FEA model as well as the experimental test investigated the surface temperature distribution on 316L stainless steel at scanning speed of 100mm/min, 125mm/min 160mm/min, 200mm/min and 250mm/min. The parametric properties of the heat source maintained constant are; lead distance Ld =10mm, focus height Fh=7.5mm, oxygen gas pressure Poxy=15psi and acetylene gas pressure Pacty=25psi. An experimental validation of the temperature field induced on type 316L stainless steel reveal that temperature distribution increases when the travelling speed decreases.

Numerical Analysis of Hot Stamping Mold Cooling System Based on FLUENT

Cooling is very important in the process of hot stamping process of a link, directly affect the mechanical properties and service life of the forming parts. Mold cooling system is effective and reasonable, therefore, is the important indicators of the hot stamping process performance. This paper deeply analyzes the hot stamping process and heat transfer theory, summarizes the main factors affecting mold cooling system performance. At the same time, the fluid analysis software FLUENT is adopted to U artifacts a numerical simulation of the hot stamping process analysis of mold during the cooling process, the work piece temperature field change, for the hot stamping mold cooling system design to provide theoretical reference.

DEFORM-3D Based on Machining Simulation during Metal Milling

Machining of metals make use of thermal mechanical FEM model. Analysis of nonlinear elastoplastic finite element simulation of milling of 45 # steel material use software of DEFORM-3D that is finite element simulation technology. DEFORM-3D software could be carried out on prediction of the milling force. Through finite element analysis, distribution of stress field, strain field and temperature field of workpiece and tool is obtained under the influence of thermal mechanical. The prediction accuracy of the model was validated experimentally and the obtained numerical and experimental results were found in good agreement.

Thermal Mechanical Coupled 3D Finite Element Simulation of Large H-Beam in Hot Rolling Process

In order to research the forming process of H-beam, based on the large H-beam production line of HN600x200, the Standard and Explicit solver of ABAQUS are synthetically used to establish finite element model for rolling process and inter-pass thermolysis process. The reciprocation multi-pass rolling process simulation procedure based on the re-meshing technology is used to simulate the whole production process form blanks to finish products, and the continuity of data is ensured. Based on the simulation results, the deformation and rolling force of the roller as well as the metal flowing law and temperature field of workpiece are discussed emphatically. The results clearly show that the displacement of roller contains the elastic deformation and the deflection, and the counterforce of left adds to the counterforce of right is about equal to the resultant force. The simulation results are compared with the measuring results, which proves the correctness of simulation.

Finite Element Simulation of Large H-Beam in X-H Rolling Process

In order to research the hot rolling process of large H-beam, the thermal-mechanical coupling analysis and big distortion theory are used to simulate the whole X-H rolling process of HN900x300 by ABAQUS, in which the re-meshing technique is taken into simulation to increase the accuracy. Based on the simulation results, the stress and deflection of the roller as well as the metal flowing law and temperature field of workpiece are discussed emphatically. The results clearly show that the roller is subjected to alternating shear force and compressive stresses of three directions, and the metal of flange tends to flow from outside to inside. The simulation results are compared with the measuring results, which proves the correctness of simulation.

Numerical Simulation of Temperature Field of Linear Friction Welding of 45# Carbon Steel

A 3D finite-elements model of 45# carbon steel of linear friction welding is built with the dynamic explicit code ABAQUS/explicit. The temperature field of workpiece, and the temperature change of center point of welding interface are showed in results. The center temperature of welding interface soars to 800°C, but the temperature of both ends of the welding interface are only 400°C or so at 0.75s. Then, the interface temperature rises slowly to about 920°C and maintains until welding ends.

3D Numerical Simulation of Linear Friction Welding of 45# Carbon Steel

A 3D finite-elements model of 45# carbon steel of linear friction welding is built with the dynamic explicit code ABAQUS/explicit based on the solution of several key techniques, such as contact boundary condition treating, material properties definition, meshing technology, etc. Then the reliability of the model is validated by comparison with experiments in the literature. Furthermore, numerical simulation and analysis of the linear friction welding process of 45# steel have been carried out by using the model. The temperature field of workpiece, the temperature change of center point of welding interface and the metal flow behavior of welding interface are showed in results.

Analysis on Temperature Field of Work-Piece during Cross Wedge Rolling

Based on the rigid-plastic deformation finite element method and the heat transfer theories, the forming process of cross wedge rolling was simulated with the finite element software DEFORM-3D. The temperature field of the rolled piece during the forming process was analyzed. The results show that the temperature gradient in the outer of the work-piece is sometimes very large and temperature near the contact deformation zone is the lowest while temperature near the center of the rolled-piece keeps relatively stable and even rises slightly. Research results provide a basis for further study on metal flow and accurate shaping of work-piece during cross wedge rolling.

Research on 3D Numerical Simulation and Experiment of Cutting Temperature for High Speed Milling of Aerospace Aluminum Alloy

To investigate the distribution of cutting temperature in high speed milling for aerospace aluminum alloy 7050-T7451.The contact temperature of work piece with tool in high speed milling process of aerospace aluminum alloy 7050-T7451 is simulated based on the analysis and simplification of the heat transfer model for the milling process with helical tool.The key techniques are studied,which include the calculation of heat source strength and application of heat load.The milling experiment is carried out in the same cutting conditions.The simulation results agree well with the experiment results.It shows that the established cutting temperature model can be used to simulate the distribution of work piece temperature field accurately in high speed milling.

Laser ablation simulation for copper

In this paper, a laser milling simulator package is shown and discussed. The software system has been developed to simulate the micro-manufacturing process using solid state lasers with pulse width in the range of 10?100 ns. The system can simulate the effects of the laser beam on the workpiece, keeping into account the surface conditions, the evolution of the workpiece temperature field, the phase changes in the material and the plasma plume effects. Simplifications concerning fluidodynamic and energy dispersions of the plasma plume are proposed. In particular, two empirical tuning parameters are considered: the first one is a global dispersion factor that keeps in account the fraction of energy lost in the environment by the plume; the second one is a spreading factor that permits to model the irradiated energy of the laser beam hitting the workpiece. The direct and coupled effects of these two parameters are evaluated and discussed.

3D Thermal Mechanical Coupled Elasto-Plastic Finite Element Analysis in the Whole Rolling Process of H-Beam

In the H-beam rolling process, the deformations and temperature field of workpiece significantly influence the mechanical properties due to the change of product microstructure. Prediction of them is important for the groove design and passes sequences. To get the deformation behavior and the temperature field of workpiece, commercial FEM program LS-DYNA has been used to analyze the whole process of H-beam rolling. The approach is based on 3D thermal mechanical coupled finite element method. The rolling process is divided into several units for calculation. The mesh of workpiece is rebuilt in the simulation for reducing the influence of element distortion. The result shows that, the temperature at the wed to flange position maintains the highest during the whole rolling process, while area of the web the lowest. After the rolling, temperature difference is above 150K between the web’s surface and flange’s inside surface, approximate 130K on the flange’s outside surface and 200K in the cross section. The simulation results show good agreement with the measured temperature data.