从建立４ 轴球体研磨机弹簧加压球体研磨的力学模型入手，运用高点切削作用机制和误差趋小化效应，解释了球体圆度误差趋小化机理并得到了试验验证。由４ 研具对球面研磨的包络原理，提出了未研磨包络区是产生残存圆度误差（圆度误差趋小值）的主要因素，并用试验结果证明了研磨压力、研磨速度、磨料粒度是决定球体研磨圆度趋小化进程的主要工艺参数。 Starting with the establishment of the mechanical model of 4-axis ball mill spring-loaded ball grinding, the mechanism of high-point cutting and the effect of the error reduction are explained, and the mechanism of the ball roundness error reduction is explained and verified by experiments. According to the principle of envelope grinding of 4 grinding tools, it is proposed that the non-grinding envelope area is the main factor that causes the residual roundness error (the rounding error is small), and the test results prove that the grinding pressure, grinding speed, It is the main process parameter that determines the rounding process of ball grinding.