The paper discusses a new method of square surface for NC processing.The problem is analyzed on existent processing method.Error is calculated in the convexity and concavity processing.

• 针对目前二阶表面加工存在的问题,论述了一种二阶表面数控加工的新方法,分析现存方法存在的问题,计算了凹凸面加工中的偏差。