Valve housing machining on a CNC vertical turning center is a high-precision CNC machining method. Here are the steps that might be involved in a typical situation:

1. CNC program writing: First, you need to write a CNC program, which is usually generated by CAM software. The program contains the geometric information of the workpiece, tool path, cutting speed, feed speed and other parameters.

2. Workpiece clamping: Firmly clamp the valve housing on the workbench of the CNC vertical turning center. Make sure the workpiece is clamped securely to prevent movement or vibration during machining.

3. Tool selection: Select appropriate tools according to processing requirements. This depends on the workpiece material, shape and processing steps. Common tools include turning tools, drill bits, milling cutters, etc.

4. Coordinate system setting: Determine the coordinate system of the CNC system to ensure that the tool path in the program matches the actual position of the workpiece.

5. Process parameter setting: Set cutting speed, feed speed, cutting depth and other processing parameters. The selection of these parameters depends on the workpiece material and the required machining accuracy.

6. Automatic measurement and compensation: CNC systems usually have automatic measurement functions that can detect tool wear and compensate for it to maintain machining accuracy.

7. Processing operation: Start the CNC program, and the CNC vertical turning center will automatically process according to the predetermined path and parameters. This may include operations such as turning, drilling, milling, etc.

8. Cooling and Lubrication: Coolant is used to cool the tool and workpiece during machining, while providing lubrication to reduce friction.

9. Quality inspection: After completing processing, quality inspection is performed to ensure that the workpiece meets the design requirements. Measurements of dimensions, surface roughness, etc. may be required.

10. Cleaning and maintenance: Clean the processing area, regularly inspect and maintain various components of the CNC vertical turning center to ensure the normal operation of the equipment.

These steps may vary depending on the design requirements and material properties of the valve housing. Also, make sure to follow safe operating procedures to prevent accidents.