The following factors should be considered when selecting the accuracy of CNC vertical lathe:

1. Processing requirements: First of all, it is necessary to clarify the accuracy requirements of the parts to be processed. According to the size, shape, material and functional requirements of the workpiece, determine the required range of machining accuracy. Different workpieces may have different requirements for precision.
2. Processing technology: Different processing technologies have different requirements for precision. For example, for parts that involve assembly and cooperation, such as bearing housings, higher precision may be required to ensure the accuracy of assembly. And some parts with simpler structures may have relatively lower precision requirements.
3. Cutting material: different materials have different machining accuracy requirements. Materials with higher hardness may require higher machining accuracy to ensure the quality and dimensional control of the machined surface.
4. Process stability: high-precision machining usually requires higher process stability. If there are problems such as large vibration, thermal deformation or insufficient rigidity of the machine tool itself during processing, it may affect the processing accuracy of the parts.

Generally speaking, the accuracy of CNC vertical lathe can be selected through the following aspects:

1. Understand the accuracy specifications provided by the manufacturer of the machine tool, such as the positioning accuracy of the workbench, repeat positioning accuracy and other parameters.
2. Consider the structural stability and rigidity of the machine tool, as well as the equipped precision servo system and measuring device.
3. Consider the control system capability of the machine tool, such as the control accuracy and feedback mechanism of the CNC system, and whether it can meet the required machining accuracy requirements.
4. Refer to the user feedback and evaluation of the machine tool to understand its machining accuracy performance in actual production.

In short, the accuracy of CNC vertical lathe selection should be comprehensively considered according to specific processing requirements, technology, materials and other factors, and evaluated in combination with the technical indicators and actual performance of the machine tool. If higher machining accuracy is required, a higher-precision CNC vertical lathe should be selected to ensure that the accuracy requirements can be met.