立式坐标镗床静刚度正向设计方法
Top-down Design Method for Static Stiffness of Vertical Coordinate Boring Machine Tools
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摘要: 整机静刚度是评价数控机床加工性能的重要指标之一, 反映了整机结构在稳态切削力作用下抵抗刀具-工件间相对弹性变形的能力, 良好的静刚度是数控机床设计的出发点和目标。目前国内的静刚度设计多利用有限元建模仿真分析, 解算整机末端三维静刚度。在此基础上, 该文以精密立式坐标镗床为研究对象, 提出了一种结构部件静刚度系数表征方法, 基于多体系统理论构建了整机静刚度模型, 明确了整机末端与各构件静刚度之间的映射关系; 采用试验设计方法进行了各构件静刚度贡献率分析, 并借助神经网络模型建立了结构件静刚度与其关键尺寸参数之间的映射关系, 在此基础上, 实现了面向整机末端静刚度约束的构件静刚度匹配设计。最后借助于整机及结构件静刚度试验验证了理论方法的准确性, 形成了系统的立式坐标镗床整机静刚度正向设计方法。所提出的设计方法能够指导机床静刚度正向设计, 具有一定的实用价值。Abstract: The entire machine static stiffness is one of the critical metrics for assessing the machining performance of CNC machine tools, reflecting the machine's structural capability to resist relative elastic deformation between the tool and the workpiece under steady-state cutting forces. Adequate static stiffness is the fundamental starting point and target for the design of CNC machine tools. Currently, domestic static stiffness design predominantly relies on finite element modeling and simulation analysis to compute the three-dimensional static stiffness at the machine's terminal. On this basis, this paper took the precision vertical coordinate boring machine as the research object. Based on this, a static stiffness model of machine tool was established using multibody theory, a characterization method for the static stiffness coefficients of structural components was proposed, and the relationship between the entire machine static stiffness and the static stiffness of individual structural components was clarified. With the entire machine static stiffness required by users as the target, structural component static stiffness contribution analysis was conducted using experimental design methods, thereby achieving entire machine static stiffness matching and obtaining the static stiffness values of each component. By constructing a neural network model, a mapping relationship between structural component static stiffness and its dimensions was established, completing the design of vertical coordinate boring machine tool structural component dimensions. Finally, the accuracy of the theoretical results was verified through static stiffness experiments, forming a systematic forward design method for the entire machine static stiffness of machine tool. The proposed design method can guide the top-down design of machine tool static stiffness and has a certain practical value.
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