自由曲面三元叶轮5轴数控粗加工刀位生成算法

针对自由曲面三元叶轮的特点，将鼓锥形刀具引入到三元叶轮粗加工中，提出了基于动态模型的刀位生成算法．该算法引入时间因素，即时计算各时间节点叶轮特征曲面，建立了动态模型模拟加工过程，能真实地反映刀具与叶轮的空间关系，降低了加工病害发生的可能性；采用等距离偏置法生成走刀轨迹，进而计算粗加工刀位信息，并通过干涉检验进行刀位修正．由于鼓锥形刀具与被加工曲面具有良好的曲率匹配性，从而增大了加工带宽，可实现宽行线接触加工．与此同时，通过对进刀深度、偏置距离的合理优化，避免走刀冗余，减少了刀迹总长度，从而提高了加工效率．实例证明由此生成的粗加工刀位具有高效、可靠的特点，效率比同直径球头刀具等距离偏置法提高约27．5％．

Cutter Location Path Generation for 5-Axis Numerical Control Rough Machining of 3-D Sculptured Surface Impeller

According to the characteristics of the 3-D sculptured surface impellers, a drum-taper cutter was adopted in NC rough machining of impellers and a new algorithm of cutter location path generation was proposed based on the dynamic model.By introducing a time factor into calculating characteristic surfaces of each time node, this algorithm builds a dynamic model which represents correctly the spatial relation between the cutter and impeller in the machining process, and reduces the possibility of machining faults.The cutter-contact path was obtained via offsetting characteristic surface with constant distance and it was calculated and corrected by the interference checking.Because of the good curvature match between the cutter and the surface, the machining width in each path is increased and thus the line-contact machining is realized.In addition, cutter path redundancy is avoided and the total length of path is reduced by the reasonable optimizing of feed depth and offset distance, and the manufacturing efficiency is largely improved.The machining example shows that this proposed algorithm is efficient and reliable. Compared with constant-distance offset method using the ball-end tool with same diameter, the efficiency of this algorithm is improved about 27.5%.