In CNC vertical lathe processing, it is crucial to find the workpiece positioning datum plane, because the selected positioning datum can directly affect the positioning accuracy and reduce the deformation of the workpiece. The following are the general steps for finding the workpiece positioning reference plane:

1. Analyze the shape and processing requirements of the workpiece: First, it is necessary to carefully study the shape, size and processing requirements of the CNC vertical lathe workpiece. Understanding the characteristics of the workpiece can help determine the best reference plane for positioning.

2. Select the positioning datum plane: CNC vertical lathe processing generally focuses on end face positioning or positioning on the inner and outer circle center axis. According to the characteristics and processing requirements of the CNC vertical lathe workpiece, select the appropriate positioning datum plane. For example, for a workpiece with a regular shape, the outer circular surface can be selected as the positioning datum; for a workpiece with a central hole, the center hole can be selected as the positioning datum.

3. Design fixtures and clamping solutions: The CNC vertical lathe designs appropriate fixtures and clamping solutions based on the selected positioning datum plane. The CNC vertical lathe fixture should be able to hold the workpiece stably and ensure that the positioning datum plane is aligned with the coordinate system of the machine tool.

4. Adjust the machine tool coordinate system: After installing the fixture and workpiece on the CNC vertical lathe, the machine tool coordinate system needs to be adjusted so that the origin of the coordinate system coincides with the positioning datum plane. This can be achieved by using the measuring function of the machine tool or external measuring equipment.

5. Verify the positioning accuracy: After the CNC vertical lathe completes the coordinate system adjustment, conduct trial processing or measurement operations to verify whether the positioning accuracy of the workpiece meets the processing requirements. If the requirements are not met, the fixture, clamping plan or positioning datum needs to be readjusted.

In the process of finding the workpiece positioning reference plane, you should also pay attention to the following points:

1. Ensure that the CNC vertical lathe positioning reference surface has sufficient stability and accuracy to avoid errors or deformation during the processing process.

2. Minimize the number of CNC vertical lathe clamping times and the frequency of fixture replacement to improve processing efficiency and reduce production costs.

3. When designing fixtures and clamping solutions for CNC vertical lathes, the processing sequence and processing path of the workpiece should be fully considered to ensure the smooth progress of the processing process.

In short, finding the CNC vertical lathe workpiece positioning reference plane is a key step in CNC vertical lathe processing. Factors such as workpiece characteristics, processing requirements, fixture design, and machine tool adjustment need to be comprehensively considered. Through reasonable selection and adjustment, the positioning accuracy and processing quality of the workpiece can be ensured.