脉冲Nd:YAG激光熔覆技术是精密修复塑料模具最有效的方法之一，激光器的电压、电流、脉冲宽度、脉冲频率与激光的扫描速度、光斑直径等工艺参数直接影响着熔覆的质量。为了综合考虑各工艺参数的影响和简化工艺调整过程，提出了重叠率的观念，建立了重叠率的计算方程。分别采用预置熔覆法和手动送丝法在低碳钢基体上熔覆Ni基合金，获得了最佳工艺参数：单脉冲能量为6.7 J，重叠率为97.4%。利用扫描电子显微镜观察了手动送丝熔覆层存在的冶金缺陷，对其产生的原因进行了初步探讨。

The pulsed Nd:YAG laser cladding is one of the most effective methods of the precise repairing technology. It is decided by the voltage, electric current, pulse length, pulse frequency, scanning speed and beam diameter of the Nd:YAG laser. In order to fully consider the effect of these processing parameters and simply the adjustment processing parameters, spot overlap rate definition is referred. And the calculation equation of spot overlap rate is formulated. The experiment was carried out with precoated layer and wire feeding laser cladding repairing. The clad layers are found perfectly at single pulsed energy of 6.7 J and spot overlap rate of 97.4%. Different kinds of defects produced by wire feeding laser cladding are observed by SEM. The reasons of producing defects are preliminarily probed.