阀芯零件激光再制造工艺方法及试验研究

为了实现损伤阀芯零件的高质量修复，提出了一种基于几何重构与路径位姿规划的阀芯再制造工艺方法。引入再制造边界预制原则对阀芯损伤部位进行预处理设计并制定其实施步骤，基于NURBS理论实现了再制造边界曲面及待修复阀芯模型的高精度重构；采用等距截平面法生成再制造工艺路径，根据直线逼近和误差控制原理计算了各插补点坐标，并将光斑面积与插补点姿态相结合确定激光喷头动态位姿；运用ABB机器人系统进行路径与位姿校验并导出代码进行了阀芯再制造实践。结果表明：所提方法中规划路径及位姿能够有效跟随阀芯再制造边界曲面进行熔覆，形成了无气孔、无裂纹的致密涂层，涂层晶粒尺寸和平均硬度分别为14～54μm和573.6HV_0.5±51.8HV_0.5,耐冲蚀腐蚀性能提高了30.8%,满足阀芯再制造要求。

Research on Laser Remanufacturing Method and Experiments of Valve Core Parts

 In order to achieve high-quality repair of damaged valve core parts， a remanufacturing process method was proposed based on geometric reconstruction and path-pose planning. The principles of remanufacturing boundary preprocess were introduced to design the geometric characteristics of damaged parts in valve core and the implementation steps were described in detail. The boundary surface and the three-dimensional model of the valve core to be repaired were reconstructed with high precision based on NURBS theory. The remanufacturing processing path was generated using a cross-sectional plane method， and each interpolation point coordinates were calculated according to the line approximation and the error control principles. The spot area was combined with the interpolation point gesture to determine the dynamic positions of laser spray head. An ABB robot simulation system was used to verify the correctness of the laser cladding paths and the laser spray head positions. Subsequently， the remanufacturing experiments of valve core parts were performed through the execution code generated by the simulation system. The results show that the planned path and positioning in the method may effectively follow the remanufacturing boundary surface in valve core parts. The formed molten coating is relatively dense and does not find pores and cracks. The coating grain size and average hardness are as 14～54 μm and 573.6HV0.5±51.8HV0.5， respectively. The erosion resistance of the coating is improved by 30.8%. The processing method may meet the remanufacturing requirements of damaged valve core parts.