阀体零件其主孔内往往带有许多沉割槽,而这些沉割槽一般都有严格的几何尺寸要求,(各槽与基准面的轴向尺寸公差多数都是±0.20 mm),这就大大地增加了这种零件的加工难度。例如图1所示是Oy5型、 Oy8型液压汽车起重机使用的分配阀的阀体,主孔直径仅φ25 mm,孔深却达66mm,而且还有 The body parts often have a large number of undercut grooves in their main bore, and these undercut groves generally have strict geometry requirements (most of the axial dimension tolerances for each groove and datum are ± 0.20 mm) Greatly increased the difficulty of processing such parts. For example, Figure 1 shows the Oy5 type, Oy8 type hydraulic truck crane using the distribution valve body, the main hole diameter is only φ25 mm, the hole depth is up to 66mm, but also