CNC milling machines for precision machining come in a wide variety of configurations; although their specific components may differ, they share many common features. The following description uses the XK5040A CNC vertical milling machine with a lifting table as an example to illustrate its main components. The XK5040A is equipped with a FANUC 0i-MD CNC system and employs all-digital AC servo drives. The machine consists of six principal assemblies: the bed, the spindle head, the worktable, the cross-feed mechanism, the lifting table, and the cooling and lubrication system. The internal layout of the bed is well designed to ensure excellent rigidity, and four adjusting bolts are provided on the base to facilitate horizontal alignment of the machine. The coolant reservoir is integrated within the machine base.

1. Cooling System. The machine tool’s cooling system consists of a coolant pump, supply pipe, return pipe, valves, and nozzles. The coolant pump is mounted in the internal cavity of the machine tool base; it draws cutting fluid from the reservoir within the base and delivers it through the supply pipe to the nozzles, where it is sprayed onto the cutting zone to provide cooling.

2. Lubrication System and Method. The lubrication system consists of a manual lubrication pump, oil distributors, throttling valves, oil lines, and other components. The machine tool employs a periodic lubrication method: a manual lubrication pump delivers oil through the distributors to lubricate the spindle sleeve, the longitudinal and transverse guideways, and the three-axis ball screws, thereby extending the service life of the machine tool.

A Brief Discussion of Precautions in CNC Milling Machining:

1. When machining parts in the machining workshop, the safety guard door must be closed; heads and hands must not be extended into the guard door, and the guard door must remain closed throughout the machining process.

2. During the machining process, operators must not leave the machine tool without authorization; they shall maintain a high level of concentration and continuously monitor the machine’s operating status. If any abnormal conditions or accidents occur, the program must be immediately halted, the power supply disconnected, and the supervising instructor notified promptly; no other operations are permitted.

3. It is strictly prohibited to forcefully slap the control panel or touch screen, and it is also strictly prohibited to strike the worktable, indexing head, fixtures, or guideways.

4. It is strictly prohibited to open the CNC system control cabinet without authorization for inspection or touching.

5. Operators at the machining workshop shall not arbitrarily modify the internal parameters of machine tools. Intern students shall not call up or modify programs that were not written by themselves.

6. On the machine tool control microcomputer, no operations other than program operation, transmission, and program copying are permitted.

7. CNC milling machines are high-precision, large-scale equipment; except for tooling and workpieces placed on the machine table, no tools, fixtures, cutting tools, measuring instruments, workpieces, or other miscellaneous items shall be stacked on the machine.

8. Do not touch the blade tip or metal chips with your hands; metal chips must be removed using a metal hook or a brush.

9. It is prohibited to touch the rotating spindle, workpiece, or any other moving parts with your hands or by any other means.

10. It is prohibited to measure workpieces or manually change gears during machining; furthermore, it is strictly forbidden to wipe workpieces with cotton yarn or to clean the machine tool.

11. Trial operations are prohibited;

12. When moving the axes using the handwheel or the rapid traverse mode, first ensure that you can clearly see the “+” and “–” signs on the X, Y, and Z axes of the machine tool before proceeding with the movement. During movement, start by turning the handwheel slowly to verify that the machine is moving in the correct direction, and only then increase the speed.

13. When it is necessary to pause measurement of the workpiece dimensions during program execution, wait until the machine tool has come to a complete stop and the spindle has ceased rotating before proceeding with the measurement to prevent accidents.

14. If the machine tool is not used for several days, the NC and CRT sections should be powered on for 2–3 hours every other day.

15. When shutting down the machining center, wait for the spindle to come to a complete stop for 3 minutes before powering off.

Do you know what the advantages of precision parts machining are?

1. Precision part machining shortens the product manufacturing process chain and increases production throughput. Turn-mill composite machining enables all or most machining operations to be completed in a single setup, thereby reducing the overall process chain. This approach not only minimizes auxiliary setup time caused by frequent changeovers but also shortens the lead time for tooling and fixture fabrication as well as associated waiting periods, resulting in a significant boost in production rate.

2. Precision part machining reduces the number of setups, thereby enhancing machining accuracy. Fewer setups help avoid error accumulation caused by changes in datum references. Moreover, most modern turn-mill composite machining centers are equipped with on-machine inspection capabilities, enabling in-process measurement of critical manufacturing parameters and real-time precision control, which further improves product machining accuracy.

3. Precision part machining reduces floor space and lowers production costs. Although the unit price of turn-mill composite machining equipment is relatively high, the shortening of the manufacturing process chain, the reduction in the number of machines required for a given product, and the corresponding decreases in tooling and fixture inventory, workshop footprint, and equipment maintenance expenses all contribute to lower overall capital investment as well as reduced production operation and management costs.