Critical interference error can be mostly resulted from illogical tool-path generations in the penetration and retraction segments of internal cylindrical thread helical milling. Therefore, a less interference tool-path planning method is proposed for the quarter revolution penetration and retraction trajectories in internal cylindrical thread helical milling. Firstly, the parametric expression of the complete tool path of internal cylindrical thread helical milling is established; after that, a definition of eccentricity parameter m is given to adjust the radius of the penetration and retraction trajectories, and Z-axis coordinate of any point on the tool path is defined as a function of the θ; thus, the planned penetration and retraction trajectories in internal cylindrical thread helical milling with the m are derived; finally, the proper eccentricity parameter m is decided to improve the machining accuracy of thread by exploring the influence of the m on the interference error. Taking the experimental of milling, an M20 × 1.5 thread using a φ8 × 1.5 cutter as one of the examples that indicate the maximum interference error of the planning method (m = 0.4) can be reduced by 30.93%, compared with the original trajectory, and can dramatically improve the precision of internal cylindrical thread helical milling.

严重的干涉误差主要是由于内螺纹螺旋铣削的切入和退回段中刀具路径不合逻辑造成的。因此，针对内螺纹螺旋铣削中的四分之一转贯入和退回轨迹，提出了一种较少干涉的刀具路径规划方法。首先，建立了内螺纹螺旋铣削完整刀具路径的参数表达式；之后，给出偏心参数m的定义以调整穿透和缩回轨迹的半径，并将刀具路径上任何点的Z轴坐标定义为θ的函数。; 因此，推导了以m为单位的内螺纹螺旋铣削中的计划进退轨迹。最后，通过研究m对干涉误差的影响，确定合适的偏心率参数m，以提高螺纹的加工精度。以铣削实验为例，使用φ8 ×1.5铣刀作为M20×1.5螺纹的示例之一，表明铣削方法的最大干涉误差（m = 0.4）与原始轨迹相比可减少30.93％ ，可以显着提高内螺纹螺旋铣削的精度。