共查询到17条相似文献,搜索用时 153 毫秒
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为解决铣削加工热传导正问题求解中时变热流的确定问题,构建了基于热传导逆问题的热流辨识方法。首先,推导了铣削加工过程的热传导数学模型。其次,介绍了应用粒子群算法(PSO:Particle Swarm Optimization)开展时变热流辨识的方法。再次,以给定的二维热传导问题为例验证了方法的可行性。最后,结合实验数据对AISI1045钢在铣削过程中的热流变化情况进行了分析。结果表明:全局界面热流呈三阶段的非线性变化;全局辨识过程中,粒子群最优位置的适应值最大为65.638 5;界面热流计算值与实测值之间的偏差为2.635%。基本满足热流辨识的误差要求,为研究铣削加工的温度分布提供了理论依据。 相似文献
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三维有限元分析在高速铣削温度研究中应用 总被引:8,自引:0,他引:8
高速切削过程中切削温度对刀具磨损、工件加工表面完整性及加工精度有极大的影响。应用有限元法对高速铣削铝合金薄壁件过程中工件与刀具接触面温度、工件内部的温度分布进行了仿真研究,仿真过程中考虑了切削速度、进给量对切削温度的影响。通过红外热像仪对不同主轴转速下工件表面温度的测量,验证了仿真结果与试验结果比较接近。得出在高速切削铝合金过程中,随着切削速度的增加,刀具与工件接触区的温度变化存在二次效应。该结论对铝合金薄壁件加工具有重要的实用价值。 相似文献
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《工具技术》2015,(12):31-35
大进给铣削是提高钛合金等难加工材料粗加工效率的先进工艺技术之一,但其切削机理因与常规铣削不同而仍有待进一步研究。为此,以有限元法为研究手段,应用有限元分析软件Deform-3D对Ti6Al4V钛合金大进给铣削过程进行了模拟,分析了每齿进给量对铣削力和铣削温度等参数的影响。结果表明:随着每齿进给量的增加,铣削力和铣削温度均随之增加,每齿进给量对径向切深方向的铣削分力影响最大,最高切削温度出现在切屑与刀具前刀面接触且靠近刃口的位置,工件的最大等效应力分布在第一变形区。此外,与试验结果的对比分析表明,有限元模拟值与实测值的变化趋势一致,铣削力模拟值与实测值数值较为接近,但铣削温度模拟值与夹丝法半人工热电偶实测值仍相差一定数值。 相似文献
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为了获得铣齿切削时切削区域的温升分布,在分别对铣削热产生和传出的机理,以及刀具和工件之间几何关系分析的基础上,得出包含对应虚拟镜像热源的热源模型。考虑到剪切面热源和刀屑接触面摩擦热源对工件、切屑和刀具的温升作用效果的不同,根据傅里叶导热定律推导出顶刃切削时相应热源的温升计算公式,分别对3者的温升分布进行计算可以获得整个切削区域的温升分布。结果表明,铣削过程中温度随切削的深入而升高,在不改变工件和刀具材料的情况下,进给速度是影响切削温度的主要因素,改变刀盘转速对温升的影响不大。 相似文献
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J. Y. Sheikh-Ahmad F. Almaskari F. Hafeez Fanyu Meng 《Machining Science and Technology》2019,23(4):530-546
An inverse heat conduction method was used to determine the energy balance at the cutting zone in edge trimming of carbon fiber-reinforced polymer composites. Three-dimensional transient heat conduction problem was modeled and solved independently in Abaqus for both the workpiece and cutting tool. Temperatures at specific locations were also measured during cutting using thermocouples and infrared thermography. Minimizing the difference between measured and calculated temperatures allowed the estimation of the heat flux applied in each problem. The total electric power consumed in machining was also measured. The heat partition was determined from the measured and calculated energies to be 0.07, 0.56 and 0.37 for the workpiece, tool and chips, respectively. The temperature distribution in the workpiece indicated that heat penetration is shallow due to poor thermal conductivity. It was also found that the extent of estimated machining thermal damage in the workpiece is within 0.35?mm below the machined surface. 相似文献
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Hendrik Puls Fritz Klocke Drazen Veselovac 《The International Journal of Advanced Manufacturing Technology》2016,82(1-4):737-751
Thermal effects often limit the performance of cutting processes. The energy spent in cutting is almost completely converted into heat which partly flows to workpiece, chip, and tool during the process. Therefore, knowledge about this partition is valuable for the process, tool, and coolant system design or for the compensation of thermal deformations of the workpiece and machine tool. For this reason, a simulation model based on the finite element method was developed to analyze the heat partition in dry metal cutting. The model utilizes the coupled Eulerian-Lagrangian method to simulate the chip formation in orthogonal cutting and to calculate the temperature distribution within workpiece, chip, and tool. This distribution was used to compute the heat partition between workpiece, chip, and tool in dependence of relevant process parameters. Furthermore, the results were validated by orthogonal cutting experiments and summarized in a formula to calculate the rate of heat flow into the workpiece as a function of those parameters. 相似文献
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Prediction of heat transfer process in helical milling 总被引:2,自引:0,他引:2
Jie Liu Chengzu Ren Xuda Qin Hao Li 《The International Journal of Advanced Manufacturing Technology》2014,72(5-8):693-705
This paper represented a three-dimensional heat transfer model which describes the temperature distribution with the time variation in solid with conduction-convection boundary during the helical milling process. On the basis of the kinematic mechanisms of helical milling, two types of heat sources were presented; one was the first heat source (FTHS) resulting from the peripheral cutting edge, and the other one was the second heat source (STHS) resulting from the bottom cutting edge. Both effects of the FTHS and the STHS on the temperature distribution of the workpiece were investigated. The FTHS was defined as one semicircle which acted on a helical path; the STHS was defined as one straight line and the movements of which consisted of three ways: rotating around the axis of the tool, turning around the center of the hole, and moving along the axial direction. In order to accurately study the heat transfer model, a stationary coordinate established in the hole and a moving coordinate established in the heat source were developed. The transformation of coordinates and the trajectory of the moving coordinate had been illustrated. Under the two coordinates, a nonhomogeneous partial differential equation (PDE) containing heat source term was derived and was solved using the Green function approach. The heat source term was depicted using the Dirac delta function. A series of experimental tails for Ti-6Al-4V were organized. The experimental results agreed well with the data calculated using the model. The effects of different cutting parameters on the temperature rise were also investigated. 相似文献
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In view of the serious problem of milling heat in milling nickel-based superalloys Inconel 718, this paper investigates the heat transfer performance of internal cooling in end milling Inconel 718, and the superiority of internal cooling milling cutter's heat exchange ability during processing is explored. The flow field characteristics of cutting fluid and milling temperature are studied by Computational Fluid Dynamics (CFD) and Finite Element Method (FEM). Compared with external flood cooling, the principle of internal cooling with excellent heat transfer performance is explained and the influence of coolant pressure on lubrication performance is analyzed. Experiments for end milling of Inconel 718 under different cutting speeds and cooling conditions have been carried out. The results indicate that the simulated and measured temperatures showed an acceptable agreement. The internal cooling has better heat transfer performance compared with flood cooling. With the increase of coolant pressure, the heat exchange efficiency is gradually enhanced. When the coolant pressure rises from 2 bar to 10 bar, the milling temperature at the measured point inside the workpiece reduces by 27.55 °C, the surface roughness reduces by 12.0%, the surface residual compressive stress increases by 68.37 MPa and better surface morphology is obtained. Besides, in the experimental range, with the increase of cutting speed, milling temperature increased, the pile-up effect on the sides of scratching was weakened and better machined surface integrity was found. 相似文献