共查询到10条相似文献,搜索用时 187 毫秒
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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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Zhongqun Li Qiang Liu 《The International Journal of Advanced Manufacturing Technology》2013,66(9-12):1415-1425
Helical milling is used to generate holes with a cutting tool traveling on a helical path into the workpiece in which the diameter of the hole can be adjusted through that of the helical path. Based on an improved Z-map model, a 3D surface topography simulation model is established to simulate the surface finish profile generated after a helical milling operation using a cylindrical end mill. The surface topography simulation model incorporates the effects of the relative motion between the cutting tool and the workpiece, in which the effect of the insert runout error of the cutting tool is considered. Furthermore, the roughness parameters are deduced from simulations of the 3D surface topography. The experimental result shows that the proposed simulation algorithm can predict well the surface roughness in a helical milling operation. The surface topography simulation model is used to study the effects of cutting conditions such as the tangential feedrate, the diameter of the cutting tool and the hole, the insert runout error of the cutting tool, as well as the revolution of the cutting tool around the axis of the hole on the surface finish profile. It is found that the surface quality can be improved by optimization of the cutting conditions. As a result, the proposed model will be helpful in determining the cutting conditions to meet surface finish requirements in helical milling operation. 相似文献
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Hao Li Gaiyun He Xuda Qin Guofeng Wang Cui Lu Linjing Gui 《The International Journal of Advanced Manufacturing Technology》2014,71(5-8):1511-1523
This paper focused on combined study on the evolution of tool wear and its influence on borehole quality in dry helical milling of Ti-6Al-4V. The carbide tools with TiAlN coating were used in this experimental investigation. The tool wear characteristics both at front and periphery cutting edges were investigated using an optical microscope and SEM-EDS techniques. The experimental results demonstrate that the combined effects of chipping/fracture, diffusion, and oxidation have significant bearings on front cutting edge failure, while the flank wear was predominant at the periphery cutting edges. The cutting speed was correlated with tool failure mechanizes, and the different wear rates at front and periphery cutting edge caused different variation trends of cutting force in thrust and horizontal direction during hole-making process. The quality of machined holes was evaluated in terms of geometry accuracy, burr formation, and surface roughness. The exit-burrs of machined hole were closely correlated with front cutting edge wear. However, high hole quality was observed even the near end of tool life from the point of view of diameters, roundness error, and surface finish due to the smooth wear pattern at periphery cutting edges. Severe tool wear at front cutting edges will cause excessive exit-burrs, but it has no obvious effect on geometry and surface roughness in helical milling of Ti-6Al-4V. 相似文献
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AbstractIn drilling in titanium alloys, heat trapped in a hole adversely affects tool life, hole surface quality and integrity. Therefore, modeling temperature distribution in drilling is vital for effective heat dissipation and improving quality of drilled surfaces. The existing numerical and finite element models consider only frictional heat, whereas the effect of shear heat generation and tertiary heat generation is neglected. In the present work, a comprehensive thermal model of the drilling process is developed by considering all heat generated in shear, friction and tertiary zones. The drill cutting edges are divided into a series of independent elementary cutting tools (ECT). The calculated heat flux loads are applied on an individual ECT in the finite element model to determine the temperature distribution and the maximum temperature around the cutting edge. The temperature in the drill was also measured experimentally with the help of an Infrared (IR) camera. The results of numerical simulations lie within the error of ~8.75% when compared to the prior studies, and ~5.41% when compared to our experimental work. The thermal model gives the temperature distribution, and the maximum temperature observed at the corner of cutting edge was 604.2°C at a cutting speed of 35?m/min. 相似文献
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A theoretical cutting force model for helical end milling with cutter runout is developed using a predictive machining theory, which predicts cutting forces from the input data of workpiece material properties, tool geometry and cutting conditions. In the model, a helical end milling cutter is discretized into a number of slices along the cutter axis to account for the helix angle effect. The cutting action for a tooth segment in the first slice is modelled as oblique cutting with end cutting edge effect and tool nose radius effect, whereas the cutting actions of other slices are modelled as oblique cutting without end cutting edge effect and tool nose radius effect. The influence of cutter runout on chip load is considered based on the true tooth trajectories. The total cutting force is the sum of the forces at all the cutting slices of the cutter. The model is verified with experimental milling tests. 相似文献
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对ABAQUS软件进行了二次开发,以实现拼接模具铣削过程仿真前处理的快速建模。对铣削力、应力和刀具温度进行仿真,并与铣削实验结果对比,验证了仿真模型的准确性。对不同前角、后角、螺旋角及刃口半径的球头铣刀铣削拼接模具的过程进行模拟仿真,采用遗传算法优化铣刀结构,将优化后的结构参数与传统结构参数代入刀具磨损、工件表面质量的对比实验,从而验证了优化的有效性。研究表明,对仿真前处理进行快速建模的二次开发运行成功,模拟结果准确。研究结果为降低制造成本、提高铣刀寿命和工件表面质量提供了理论参考。 相似文献
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