数控系统对数控机床加工精度的影响因素探究

Exploring the Factors Influencing the Processing Accuracy of CNC Machine Tools by CNC Systems

【目的】为了进一步提高国产数控系统的综合性能,提高产品竞争力,使国产制造走向高端制造、精密制造,探究清楚数控系统对数控机床加工精度的影响因素十分重要。【方法】笔者在数控机床结构、机械硬件和环境相同的情况下,分别采用华中数控系统和FANUC数控系统加工二维、三维六边形零件和三维球面零件,然后用加时特蔡司三坐标与华中雷尼绍三坐标测量仪对相同的数据点进行采集、测量、比较,分析导致其加工精度不同的原因。【结果】1)在设计加工测量零件时,没有设计合理的测量基准供三坐标使用,造成三坐标无法测量或测量误差整体偏大。2)测量基准的加工尺寸及表面质量差,直接影响到三坐标测量时建立坐标系的基准误差,造成测量尺寸偏大。3)多把刀加工、手动对刀等也会导致加工后与测量基准不一致。4)加工时,零件本身存在误差,如编程精度、模型造型精度等都会影响加工尺寸的精度。【结论】国产数控系统与国外数控系统的加工精度基本一致,但在一些局部加工特征方面,整体的数控系统加工设计还需要进一步优化。

[Objective]In order to further improve the comprehensive performance of domestic CNC systems,enhance product competitiveness,and move domestic manufacturing towards high-end and precision manufacturing,it is important to explore the factors that affect the machining accuracy of CNC machine tools by CNC systems.[Method]The author uses Huazhong CNC system and FANUC CNC system to process two-dimensional,three-dimensional hexagonal parts and 3-sphere parts respectively under the same condition of the structure,mechanical hardware and environment of CNC machine tools.Then,the same data points are collected,measured and compared with the time-lapse Zeiss CMM and Renishaw CMM,and the reasons for the different processing accuracy are analyzed.[Result]1)During the design and processing of measuring parts,there was no reasonable Geodetic datum designed for the use of three coordinates,which caused that three coordinates could not be measured or the overall measurement error was too large.2)The processing size and surface quality of the Geodetic datum are poor,which directly affects the datum error of establishing the coordinate system during the three coordinate measurement,resulting in the measurement size being too large.3)Machining with multiple cutters,manual tool setting,etc.will also lead to inconsistency between the processed tool and the Geodetic datum.4)During machining,there are errors in the parts themselves,such as programming accuracy and model modeling accuracy,which can affect the accuracy of machining dimensions.[Conclusion]The machining accuracy of domestic and foreign CNC systems is basically the same,but in some local machining features,the overall machining design of the CNC system still needs further optimization.