在薄壁件铣削过程中，颤振对工件表面质量有很大影响，在实际加工之前进行铣削稳定性预测，便于获取无颤振的加工条件。本文基于径向基函数逼近理论，提出一种铣削稳定性预测方法。通过试切法和锤击法获得了AL2A12薄壁件的切削力系数和模态参数，并基于所提出的方法推导了系统的状态转移矩阵，通过Floquet定理来判定系统的稳定性，从而获得了AL2A12薄壁件铣削过程的稳定性图。为了验证本文所提方法的计算效率，采用相同的系统参数来进行计算。通过与零阶半离散法和全离散法相比，表明在获得的铣削稳定性图一致的前提下，本文所提方法的计算效率最高。在预测的稳定性图中选择4个参数点，利用参数点所对应主轴转速和轴向切深来加工AL2A12薄壁件，将实际加工结果与稳定性预测结果进行比较，验证了所提预测方法的有效性。通过实际切削表明，在AL2A12薄壁件的加工过程中，当轴向切深相近时，较高的主轴转速可以获得更好的加工表面，同时也可以避免粘刀现象的产生。
Abstract
During a thin-walled workpiece's milling, its surface quality is greatly affected by chatter. Chatter free condition can be obtained if the milling stability is predicted before practical machining. Here, a milling stability prediction method was proposed based on the radial basis function approaching theory. The cutting force coefficients and modal parameters of the AL2A12 thin-walled workpiece were acquired with cutting tests and hammer tests, respectively. The state transfer matrix of the milling system was deduced with the proposed method, and the stability lobe diagram was determined with Floquet theorem. In order to verify the computational efficiency of the proposed method, the same system parameters were used in different methods. Compared with the zeroth-order semi-discretization method and the full-discretization method, it was indicated that the proposed method has the highest computational efficiency under the premise that the stability lobe diagrams obtained with different methods are coincident. Then, the AL2A12 thin-walled workpiece was machined with the given spindle speeds and axial cut depths being corresponding to the four points selected from the predicted stability lobe diagram. The effectiveness of the proposed method was verified through comparing the machining results with the prediction ones. The practical machining showed that better machined surface can be obtained with higher spindle speed when the axial cut depths are close to each other, the milling tool sticky phenomenon can also be avoided with higher spindle speed.
关键词
薄壁件 /
铣削稳定性 /
径向基函数 /
Floquet定理
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Key words
thin walled workpiece /
stability prediction /
radial basis function /
floquet theorem
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参考文献
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