数控机床加工过程综合误差数学模型

Synthesis Error Model for Numerical Control Machining

针对影响数控机床加工精度的几何误差和切削力导致的误差,识别出了三轴数控铣床加工过程中的21项几何误差元素和35项切削力误差元素,应用齐次坐标变换原理,推导出了各部件存在误差时相对于相邻部件的齐次坐标变换矩阵。由于加工过程中的数控机床可以看成是一个传动链,链的一端是工件,另一端是刀具,并且工件的理论被切削点和刀具的理论切削点在机床基本坐标系中的坐标是相同的,根据此关系,推导出了包含几何误差和切削力误差的数控机床加工过程综合误差数学模型。

The geometric error and the error caused by cutting force of CNC machine tools co-existed,they affected the quality of the workpiece.The 21 geometric error elements and 35 error elements caused by cutting force of a 3-axis CNC machine tools were identified.Based on the homogeneous coordinate transformation method,the coordinate systems on the transmission components of machine tool were set up.Then the homogeneous coordinate transformation matrixes were deduced between the two connective movement components.So the cutting point of the tool and the point to be cut of the workpiece have the same space position in the base coordinate system.The error synthesis model of the geometric error and the error caused by cutting force is worked out.