球头刀三轴数控铣削的机床几何误差补偿研究

Study on Compensation of Machine Geometry Error for Three-axis CNC Milling with Ball-end Mill

工艺系统中机床几何误差使零件产生加工误差,为避免此误差,本文以球头刀三轴数控铣削为背景,利用激光干涉仪与“九线法”辨识方法,测量并辨识机床几何误差。基于多体系统理论和旋量理论,建立球头刀三轴数控铣削空间误差模型,将机床几何误差映射到球头刀刀心的位置误差。根据球头刀三轴数控铣削时工件表面成形原理、刀心曲面与设计曲面/工件表面之间的计算模型,建立编程刀心曲面。将编程刀心曲面导入CAM软件进行数控编程,利用生成的加工程序进行加工,即可补偿机床几何误差。

There are various errors in the process system,which will cause machining errors in the parts,among which the machine geometry error is the more influential factor.Based on three-axis NC milling with ball-end mill,the geometric error of machine tool is measured and identified by laser interferometer and"nine line method"identification method.Based on the multi-body system theory and the screw theory,the three-axis milling spatial error model of the ball-end mill is established,and the geometric error of the machine tool is mapped to the position error of the ball-end mill center.According to the forming principle of workpiece surface in three-axis milling with ball-end mill,the programming cutter center surface is established by establishing the forward and reverse calculation model between the cutter center surface and the design surface/workpiece surface.The programmed tool center surface is imported into the CAM software and CNC programmed for the surface,which is machined using the generated machining program to compensate for machine geometry errors.