Before using a CNC (computer numerical control) milling machine, it is important to understand the following:

1. The basics of CNC technology: Understanding the basic principles of CNC technology, including how the machine is controlled and programmed, is essential for proper use.

2. Programming languages: CNC milling machines use specific programming languages, such as G-code, to control the machine's movements and cutting operations. Familiarity with these languages is essential for creating accurate and efficient programs.

3. The different types of CNC milling machines: There are various types of CNC milling machines, each with its own unique capabilities and limitations. It's important to understand the specific capabilities and limitations of the machine you will be using.

4. Safety procedures: As with conventional milling machines, CNC milling machines can be dangerous if used improperly, so it's important to understand and follow proper safety procedures.

5. Machine maintenance: CNC milling machines require regular maintenance to ensure they function properly. Understanding how to properly maintain the machine is essential for prolonging its lifespan and maintaining accuracy.

6. CAD (Computer-Aided Design) and CAM (Computer-Aided Manufacturing) software: CNC milling machines typically rely on specific CAD and CAM software to create and edit designs, as well as create the machine code. Familiarity with these software will help you to design and create complex parts.

7. How to set up and operate the machine: It's important to understand how to properly set up and operate the CNC milling machine, including loading and editing programs, setting up the workpiece, and monitoring the machine during operation.

Using a CNC Milling Machine:

1. Make sure the machine is plugged in and turned on.
2. Load the appropriate program into the machine's control system.
3. Set up the workpiece on the machine's table, making sure it is securely fastened.
4. Press the start button or initiate the program to begin cutting.
5. Monitor the machine during operation to ensure it is running correctly and make any necessary adjustments.
6. Once the cut is complete, turn off the machine and remove the finished piece.

Maintaining a CNC Milling Machine:

1. Keep the machine clean and free of debris.
2. Lubricate the machine as recommended by the manufacturer.
3. Check and tighten all bolts and screws on a regular basis.
4. Inspect the cutting tools and replace them when they become dull or damaged.
5. Check and adjust the alignment of the machine's components as needed.
6. Regularly check the machine's coolant levels and clean or replace filters as necessary.
7. Have the machine serviced by a qualified technician when necessary.
8. Always follow safety guidelines when using and maintaining the machine.
9. Keep the software updated and make sure the machine's control system is working correctly.
10. Make sure the machine is well calibrated, it will help you to achieve high precision.