CNC vertical lathe can complete thread cutting through the following steps:

1. Determine processing parameters: Before thread processing, it is necessary to determine the specifications and parameters of the thread, such as pitch, thread direction, nominal diameter, etc. According to the thread parameters, set the appropriate CNC programming.
2. Workpiece clamping: Fix the workpiece that needs to be threaded on the workbench of the CNC vertical lathe to ensure the stable clamping of the workpiece to ensure the accuracy and quality of thread processing.
3. Select the tool: Select the appropriate cutting tool according to the thread parameters, usually use the thread cutter for thread processing. Tool selection should consider factors such as thread specification and workpiece material.
4. Set the cutting speed and feed: according to the workpiece material and tool type, set the appropriate cutting speed and feed. These parameters have a significant impact on the quality and efficiency of threading.
5. Write NC programs: Write NC programs according to thread parameters and processing requirements. Programs include tool paths, cutting parameters, feed commands, etc. to achieve correct threading operations.
6. Start processing: load the CNC program into the control system of the CNC vertical lathe, and start the processing process. The machine tool will automatically perform threading operations according to the set tool path and cutting parameters.
7. Inspection of thread size and quality: After processing, use thread measuring tools, such as thread micrometers or thread gauges, to inspect the size and quality of processed threads. According to the inspection results, evaluate the eligibility of thread processing.

Please note that before threading, the operator needs to have corresponding operating skills and knowledge, and be familiar with the operation and programming methods of CNC vertical lathe. In addition, different models and brands of CNC vertical lathes may have different processing characteristics and operating requirements, so it is recommended to refer to the operation manual of the machine tool and the guidance provided by the manufacturer.