Machining process simulation (original) (raw)
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Manufacturing and Materials Processing Journal, 2018
This paper presents an original method of predicting temperature distribution in orthogonal machining based on a constitutive model of various materials and the mechanics of their cutting process. Currently, temperature distribution is commonly investigated using arduous experiments, computationally inefficient numerical analyses, and complex analytical models. In the method proposed herein, the average temperatures at the primary shear zone (PSZ) and the secondary shear zone (SSZ) were determined for various materials, based on a constitutive model and a chip-formation model using measurements of cutting force and chip thickness. The temperatures were determined when differences between predicted shear stresses using the Johnson-Cook constitutive model (J-C model) and those using a chip-formation model were minimal. J-C model constants from split Hopkinson pressure bar (SHPB) tests were adopted from the literature. Cutting conditions, experimental cutting force, and chip thickness were used to predict the shear stresses. The temperature predictions were compared to documented results in the literature for AISI 1045 steel and Al 6082-T6 aluminum in multiple tests in an effort to validate this methodology. Good agreement was observed for the tests with each material. Thanks to the reliable and easily measurable cutting forces and chip thicknesses, and the simple forms of the employed models, the presented methodology has less experimental complexity, less mathematical complexity, and high computational efficiency.
Applying a Numerical Model to Obtain the Temperature Distribution while Machining
Acta Physica Polonica A, 2017
The turning process is one of the best used processes in the mechanical industry. Therefore, the choice of the cutting parameters is very important in order to obtain a good machined surface quality. In this study, an analytical model and a modeling of the contact of the cutting tool with the work piece are developed for an orthogonal cutting process with a thermal analysis at the contact. The main aim is to predict the temperature while machining. By using the high-speed machining, we notice that the greater part of the heat, generated by the cutting process, is discharged into the cutting tool and the work piece. Indeed, when the cutting parameters, such as the cutting speed or the feed increase, the temperature increases too.
Modelling of temperature distribution in orthogonal machining using finite element method
2017
This work employs finite element method (FEM) to model the temperature distribution of a mild steel with a carbide cutting tool insert in an orthogonal machining. The finite element model was simulated with MATLAB and validated with experimental data. The temperature rise on the shear plane and the effect of different cutting parameters such as rake angles, cutting speed and forces were investigated. The results obtained were contour and surface plots at a bottom surface z = 0 and surface z = 0.02. It shows that the minimum and maximum temperatures of 200 and 400 K were recorded at the extreme end and tip of the tool respectively, due to high friction on the tip contact area, at the bottom surface z = 0. The minimum and maximum temperatures of 285 and 310 K at the extreme end and tip of the tool were recorded respectively, at a surface z = 0.02. In addition, it was observed that an increase in temperature caused an increase in cutting speed at different rake angles. Similarly, an in...
Determination of Thermal Material Properties for the Numerical Simulation of Cutting Processes
Research Square (Research Square), 2021
Thermal properties of work materials, which depend significantly on the change in cutting temperature, have a considerable effect on thermal machining characteristics. Therefore, the thermal properties used for the numerical simulation of the cutting process should be determined depending on the cutting temperature. To determine the thermal properties of the work materials, a methodology and a software-implemented algorithm were developed for their calculation. This methodology is based on analytical models for the determination of tangential stress in the primary cutting zone. Based on this stress and experimentally or analytically determined cutting temperatures, thermal properties of the work material were calculated, namely the coefficient of the heat capacity as well as the coefficient of thermal conductivity. Three variants were provided for determining the tangential stress: based on the normal stress calculated using the Johnson-Cook constitutive equation, based on the experimentally determined cutting and thrust forces as well as by directly calculating the tangential stress. The thermal properties were determined using the example of three different materials: AISI 1045 and AISI 4140 steel as well as Ti10V2Fe3Al titanium alloy (Ti-1023). With the developed FE cutting model, the deviation between experimental and simulated temperature values ranged from approx. 7.5% to 14.4%.
Development of a Computational Model to Investigate the Thermo-Mechanical Behaviour of Cutting Tools
2019
During machining, the cutting tool wears out and affects the machined surface quality and overall production cost. The prediction of tool wear and analysis of cutting mechanics has significant importance for process optimization and cutting-edge design. In this present study, an efficient FE simulation approach (Arbitrary Eulerian-Lagrangian) on the Abaqus/Explicit platform has been developed to improve the predictability of flank wear and to select the appropriate tool edge geometry in the orthogonal turning operation. The FE model was calibrated by comparing the simulation and experimental force values. A new approach was applied to capture the worn tool geometry based on the frictional stress value acting on the cutting tool. The effect of wear geometry on the cutting zone was investigated with respect to temperature, normal stress, sliding velocity, and plastic deformation. The experimental tool wear pattern and characteristics for the differently prepared edges were studied and compared to the thermo-mechanical value retrieved from the FE model. Tool wear for differently prepared edges was calculated using Usui's wear rate equation, which was calibrated using a hybrid calibration method. The efficiency of the calibration method was investigated at different cutting speeds and feed rates. The performance of pre-coating edge preparation was evaluated in both experimental and numerical studies.
Procedia CIRP, 2013
The paper considers the problem of the influence of constitutive model parameters on the results of FEM-based modelling of the turning process under simple orthogonal arrangement. In these simulations C45 (AISI 1045) carbon steel and multilayer-coated carbide tool were used. The orthogonal cutting model was used with varying cutting speed of v c =100-330 m/min and constant feed rate f=0.16 mm/rev and depth of cut a p =2 mm. The simulations were based on the power constitutive law (PL) with a special consideration of the temperature-related thermal influences. Both sets of literature data, i.e. Ozel's and Kalhori's models and own data in the form of multi-regressive equations for the substrate and coating components were applied. The novelty of this study is that the sensitivity analysis concerns the material flow stress in the PL model. As outputs, the average interface temperature, the distribution of temperature on the rake face and within wedge body, as well as cutting forces were determined, compared and discussed. Quite satisfactory results with simulation errors lower than 15% were obtained.
The International Journal of Advanced Manufacturing Technology, 2019
Elevated temperature in the machining process is detrimental to the cutting tool due to a thermal softening effect. The increased material diffusion deteriorates the quality of the machined part. Experimental techniques and finite element method-based numerical models in temperature investigation are limited by the restricted accessibility and high computational cost respectively. Physic-based analytical models are developed to overcome those issues. This study investigated three analytical models, namely a modified chip formation model, Komanduri-Hou two heat sources model, and Ning-Liang material flow stress model, in the prediction of machining temperatures in orthogonal cutting. The evaluation and comparison between three models aim to promote the use of the analytical models in real applications, in which real-time prediction is highly appreciated. Temperatures in machining AISI 1045 steel were predicted under various cutting conditions. Acceptable agreements were observed between predictions and documented values in the literature. In the modified chip formation model, machining temperatures and forces were solved iteratively with complex mathematical equations, which reduced computational efficiency, and thus prevented a real-time temperature prediction. The heat partition factors were empirically determined, which resulted in unoptimized prediction accuracy. In Komanduri-Hou model, the input lengths of two shear zones and shear angle cannot be easily obtained from experiments due to the restricted accessibility. With the benefits of high prediction accuracy, high computational efficiency, and low experimental complexity of model inputs, Ning-Liang model was favored in the real-time prediction of machining temperatures.
The International Journal of Advanced Manufacturing Technology, 2010
A better understanding of heat partition between the tool and the chip is required in order to produce more realistic finite element (FE) models of machining processes. The objectives are to use these FE models to optimise the cutting process for longer tool life and better surface integrity. In this work, orthogonal cutting of AISI/SAE 4140 steel was performed with tungsten-based cemented carbide cutting inserts at cutting speeds ranging between 100 and 628 m/min with a feed rate of 0.1 mm/rev and a constant depth of cut of 2.5 mm. Cutting temperatures were measured experimentally using an infrared thermal imaging camera. Chip formation was simulated using a fully coupled thermo-mechanical finite element model. The results from cutting tests were used to validate the model in terms of deformed chip thickness and cutting forces. The coupled thermo-mechanical model was then utilised to evaluate the sensitivity of the model output to the specified value of heat partition. The results clearly show that over a wide range of cutting speeds, the accuracy of finite element model output such as chip morphology, tool-chip interface temperature, von Mises stresses and the tool-chip contact length are significantly dependent on the specified value of heat partition.