在镗床上加工箱体类零件,往往一个零件上有许多孔,由于结构上的原因,有些孔的中心连线与定位基准面成一夹角。一个孔加工完后,刀具必须同时在x,y方向作相对移动才能加工另一个孔。由于设计和加工工艺的要求,图纸上一般只给出两孔中心距的基本尺寸及公差,同时给出直角坐标系中的一个坐标尺寸(见图1)。在加工过程中,设计尺寸C~(+δc)必须由尺寸 In the boring machine processing parts of the box, often a hole on the part, due to structural reasons, some of the holes in the center line and the positioning of the reference plane at an included angle. After a hole is machined, the tool must be relatively moved in the x and y directions to machine the other hole. Due to the design and processing requirements, the drawing generally only gives the basic dimensions and tolerances of the center distance of the two holes, and at the same time gives a coordinate size in the Cartesian coordinate system (see Figure 1). In the processing, the design size C ~ (+ δc) must be the size