Abstract

Geometric error measurement is crucial for error compensation and machining accuracy of CNC machine tools. However, traditional double-ball bar (DBB) method cannot be used for full-scale measurement of geometric errors due to the constant length of bars. In this paper, a full-scale measurement of geometric errors for CNC machine tools with high efficiency is carried out based on the double ball bar with a ball joint (J-DBB) method. Firstly, the principle of J-DBB is introduced. The J-DBB can be used for a full-scale measurement thanks to its freely measuring radius. Then, the equations of geometric errors which include squareness error, straightness error, roll error, pitch error, and yaw error of the axes are theoretically analyzed. In the end, we compared the theoretical trajectories of circular interpolation with the actual ones. The geometric errors between theoretical trajectories and actual ones can be measured and shown by J-DBB method. The results revealed that the J-DBB can be applied to conduct the full-scale measurement of geometric errors in CNC machine tools. Besides, the measurement range of geometric errors is extended from a two-dimensional circle to a three-dimensional sphere with a radius of 0.259L to 2L.

中文翻译：

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数控机床的全尺寸测量

摘要

几何误差测量对于CNC机床的误差补偿和加工精度至关重要。但是，由于棒的长度恒定，传统的双球棒（DBB）方法不能用于几何误差的全面测量。本文基于带球接头的双球杆（J-DBB）方法，对数控机床的几何误差进行了满量程测量。首先介绍了J-DBB的原理。J-DBB的自由测量半径可用于满量程测量。然后，从理论上分析了包括轴的直角误差，直线度误差，侧倾误差，俯仰误差和偏航误差在内的几何误差方程。最后，我们将圆弧插补的理论轨迹与实际轨迹进行了比较。理论轨迹和实际轨迹之间的几何误差可以通过J-DBB方法进行测量和显示。结果表明，J-DBB可以应用于数控机床的几何误差的全尺寸测量。此外，几何误差的测量范围从二维圆扩展到半径为0.259的三维球大号至2大号。