共查询到20条相似文献,搜索用时 140 毫秒
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在切削稳定性预测原理的基础上,建立了薄壁零件铣削稳定性的动力学模型,推导出了在稳定性极限条件下,轴向切深和主轴转速的关系,并用Matlab进行了计算仿真,得到了不同的阻尼系数、固有频率条件下的颤振稳定性图。 相似文献
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在工程实际中,车削系统刚度、阻尼及切削力等参数的随机性严重影响车削加工的稳定性。针对此问题,提出了一种车削加工再生型颤振稳定性可靠度计算方法。考虑随机因素的影响,采用蒙特卡罗数值模拟方法,研究车削加工再生型颤振稳定性的统计分布规律。建立车削加工再生型颤振动力学模型,采用拉氏变换获取机床车削的极限切削宽度及所对应的主轴转速。根据数控车床切削系统动力学参数的分布信息抽取样本,代入再生型颤振模型进行计算,获取极限切削宽度的样本,并统计其概率特性,以实际切宽是否小于极限切宽为判别条件提出一种基于蒙特卡罗模拟的车削加工再生型颤振稳定性可靠度预测方法。 相似文献
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针对数控重型切削加工过程的切削稳定性具有不确定性的特点,提出了在切削稳定性和机床工作能力的约束下,获得最大材料去除率的工艺参数优化方法。根据重型切削加工的工艺特点建立三维动力学模型,以机床的固有频率、阻尼比、刚度和切削力系数作为不确定因素,结合排零定理和边理论对其进行不确定性分析,获得稳健的切削稳定性叶瓣图,结合切削深度、刀具直径和刀具齿数的关系,为加工过程选择能获得最大切削深度的刀具。在此基础上,建立工艺参数优化模型,选择最佳的轴向切削深度、径向切削深度和主轴转速的组合,最后以一台加工中心上某型号发动机缸体表面的粗加工过程为例进行了验证。 相似文献
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Fansen Kong Junyi Yu 《The International Journal of Advanced Manufacturing Technology》2007,33(7-8):677-683
Fuzzy mathematical theory is applied to drawing the fuzzy stability lobes in which each lobe is characterized by a membership
grade of experiential distribution of testing data in the theoretical distribution set of chatter signal. The judgement of
limit value of free-chatter cutting width is spread over the fuzzy domain in this paper. The fuzzy combination relationship
between the spindle speed and the depth of cut in milling is also addressed. According to the limit width, a safety criterion
on which the cutting process is stable is developed. Also, the concept and definition of safety criterion for the cutting
process stability operation for fuzzy stochastic meaning are given. Analysis indicates that the fuzzy stability lobes have
definite physical significance. First, they can tell us in which status the cutting process is for the drawn lobe. Second,
they reflect the probability distribution of the limit value of cut width in the fuzzy domain with respect to the identification
of chatter status (fuzzy event). Meanwhile, it indicates that there is a transition between unstable lobes and stable lobes
in a stability threshold graph with the influence of both fuzzy stochastic parametric excitation and fuzzy stochastic external
excitation. Testing value curves of the fuzzy allowed domain of the limited cutting width are developed via experiment. 相似文献
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Three-dimensional stability lobe and maximum material removal rate in end milling of thin-walled plate 总被引:2,自引:2,他引:0
Aijun Tang Zhanqiang Liu 《The International Journal of Advanced Manufacturing Technology》2009,43(1-2):33-39
Chatter phenomenon often occurs during end milling of thin-walled plate and becomes a common limitation to achieve high productivity and part quality. For the purpose of chatter avoidance, the optimal selection of the axial and radial depth of cut, which are decisive primary parameters in the maximum material removal rate, is required. This paper studies the machining stability in milling of the thin-walled plate and develops a three-dimensional lobe diagram of the spindle speed, axial, and radial depth of cut. Through the three-dimensional lobe, it is possible to choose the appropriate cutting parameters according to the dynamic behavior of the chatter system. Moreover, this paper studies the maximum material removal rate at the condition of optimal pairs of the axial and radial depth of cutting. 相似文献
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正交车铣偏心加工三维颤振稳定性的研究 总被引:1,自引:0,他引:1
针对正交车铣复杂运动产生变深度、变厚度的切削特性,基于其加工原理采用解析法提出三维颤振稳定域的理论模型.在模态试验基础上,仿真分析正交车铣偏心加工颤振稳定域叶瓣图,结果表明正交车铣加工产生颤振的条件除了与铣刀几何形状和啮合条件、机床结构的频响应函数、工件材料特性等有关外,主要与铣刀轴转速和切削深度密切相关.在正交车铣切削颤振稳定域试验过程中,切削力频谱分析的结果表明:当刀齿切入频率在力频谱中起主导作用时,切削过程是无颤振和稳定的;当系统结构模态频率在力频谱中起主导作用时,将产生颤振并测得切削力和表面粗糙度值都大于或高于无颤振情况.因此该理论模型及仿真结果可以有效预测正交车铣偏心加工颤振稳定性,为其加工表面质量和加工效率提供理论指导. 相似文献
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K. C. Cha N. Wang J. Y. Liao 《The International Journal of Advanced Manufacturing Technology》2014,71(1-4):605-620
This paper aims to explore the dynamic characteristics and cutting stability of a surface grinder. In simulated grinding, the dynamically loaded worktable is described by the Euler–Bernoulli beam theory. In the model, the elastic worktable has both ends simply supported on a movable and massless rigid base. The analysis of the dynamics and stability of the worktable is complex due to the operating worktable being dynamically loaded in variable positions. With the Lagrange energy method combined with the assumed mode expansion method, the system dynamic equations are derived and a state space model for the dynamically loaded worktable subjected to simply supported conditions is developed. In this study, the maximum negative real part of the overall dynamic compliance and the limiting depth of cut are used as indicators to assess the structural static and dynamic performance of the worktable in various positions. The effects of worktable damping, contact stiffness, and damping between the tool and the workpiece on the system performance are studied. Based on the regenerative chatter and stability theory, the 3D stability lobes diagram is analyzed to optimize the maximum depth of cut at the highest available spindle speed. The cutting stability is verified by comparing the results obtained in the time domain analysis with the stability lobe diagram. The procedure illustrated in this study to improve the dynamics performance of a surface grinder can also be implemented in a similar fashion for many machine tool applications. 相似文献
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针对铝合金薄壁件的高速精密车削进行应用研究.专用向心结构夹具的设计应用,使得零件的几何精度特别是同轴度得到了有效的提高,为高速精密车削的正交试验奠定了必不可少的基础条件.PCD刀具切削铝合金的正交试验优化切削参数的研究,结果表明:在稳定的高速车削环境下,切削速度和切削深度对切削力和表面粗糙度影响较小,合理的进给速度是提升零件表面加工质量的关键因素.具有很强的实用性. 相似文献
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V. Thevenot L. Arnaud G. Dessein G. Cazenave-Larroche 《Machining Science and Technology》2006,10(3):275-287
Machining is a material removal process that alters the dynamic properties during machining operations. The peripheral milling of a thin-walled structure generates vibration of the workpiece and this influences the quality of the machined surface. A reduction of tool life and spindle life can also be experienced when machining is subjected to vibration. In this paper, the linearized stability lobes theory allows us to determine critical and optimal cutting conditions for which vibration is not apparent in the milling of thin-walled workpieces. The evolution of the mechanical parameters of the cutting tool, machine tool and workpiece during the milling operation are not taken into account. The critical and optimal cutting conditions depend on dynamic properties of the workpiece. It is illustrated how the stability lobes theory is used to evaluate the variation of the dynamic properties of the thin-walled workpiece. We use both modal measurement and finite element method to establish a 3D representation of stability lobes. The 3D representation allows us to identify spindle speed values at which the variation of spindle speed is initiated to improve the surface finish of the workpiece. 相似文献
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Machining is a material removal process that alters the dynamic properties during machining operations. The peripheral milling of a thin-walled structure generates vibration of the workpiece and this influences the quality of the machined surface. A reduction of tool life and spindle life can also be experienced when machining is subjected to vibration. In this paper, the linearized stability lobes theory allows us to determine critical and optimal cutting conditions for which vibration is not apparent in the milling of thin-walled workpieces. The evolution of the mechanical parameters of the cutting tool, machine tool and workpiece during the milling operation are not taken into account. The critical and optimal cutting conditions depend on dynamic properties of the workpiece. It is illustrated how the stability lobes theory is used to evaluate the variation of the dynamic properties of the thin-walled workpiece. We use both modal measurement and finite element method to establish a 3D representation of stability lobes. The 3D representation allows us to identify spindle speed values at which the variation of spindle speed is initiated to improve the surface finish of the workpiece. 相似文献