Doing a good job in maintenance can keep the machining accuracy of the machine tool in the best condition, extend the service life, and adopt the correct startup and debugging method for the CNC machine tool. In the face of new challenges, it can show a good working condition and improve the production efficiency and processing effect.

 

Maintenance of CNC machine tool shutdown 

There are many types of CNC machine tools, and all types of CNC machine tools have different characteristics due to their different functions, structures and systems. The content and rules of its maintenance also have their own characteristics. The specific maintenance system should be formulated and established according to the type, model and actual use of the machine tool, and with reference to the requirements of the machine tool manual. The following are some common general maintenance points.

 

1. Machine tool cleaning: clean up the workpieces, fixtures, iron filings, etc. in the machine tool, clean the iron filings in the external chip conveyor; wipe clean the external sheet metal, clean the air conditioner of the electric control box, and the filter of the oil cooler.

 

2. Anti-rust treatment: clean and wipe the workbench and apply anti-rust oil; the machine tool runs slowly for one hour to lubricate the rail; whether the cutting fluid needs to be replaced, give priority to rust prevention, and add it when the machine tool starts to work Cutting fluid.

 

3. Do the general power off, gas and liquid supply in the workshop: run the Y-axis of the CNC machine tool to the middle, return the Z-axis to zero, and turn off the power switch of the machine tool, the line switch of the transformer, and the air source.

 

4. Waterproof and moisture-proof: close the electrical box for protection.

 

5. Anti-rodent treatment of the machine tool: The machine tool should also be treated with anti-mouse to prevent the mouse from biting the wire.

 

Commissioning of CNC machine tools 

The CNC machine tool is a kind of high-tech mechatronics equipment. It is very important to start and debug in the correct way. This determines to a large extent whether the CNC machine tool can exert normal economic benefits and its own service life.

 

Check before starting: Check the peripheral environment of the machine tool, whether there is any abnormal phenomenon such as water in the electrical box, and whether the oil has deteriorated.

 

Step-by-step startup: The power supply voltage of the machine tool must be checked before startup, and the power switch of the machine tool must be turned on after the main power switch is turned on for about 10 minutes after the voltage is stable, and then turn on the other power switches in the electrical box to check whether the voltage is missing phase and If it is too low, turn on the power of the machine tool if there is no abnormality, and observe whether there is any abnormality or air leakage. Do not perform any actions when there is no alarm when the machine is turned on, and let the electrical components energize for 30 minutes.

 

Slow movement: Check for interference, move the machine tool all the way with the handwheel, and pay attention to whether there is any abnormality, and then perform the origin return step.

 

Machine tool running-in: Run the machine tool automatically and slowly for a long time, and rotate the spindle at low speed.

Frequent failures of CNC machine tools

Fan failure: The fan in the machine tool can dissipate heat and cool down the core equipment, effectively avoiding damage to the equipment due to overheating. At the end of the long vacation, the machine fan often "strikes", which is caused by oil pollution. When the machine is stopped, the fan inside the machine will also stop. At this time, the oil in the machine tool will flow into the fan's bearing, causing the fan's circuit to short-circuit and fail, and the fan will alarm or fail to start when it is turned on again. The longer the downtime, the greater the risk.

 

Seal failure: Seals are indispensably used in the hydraulic and pneumatic devices of the machine tool. The purpose is to ensure the airtightness of the device and maintain its normal pressure supply. Seals are generally rubber products and are prone to aging, especially during long holidays, when the machine does not operate for a long time and the hydraulic pressure does not flow. This is more likely to cause hardening of the seals, resulting in oil leakage from the machine tool, and insufficient pressure provided by the hydraulic device.

 

Blockage of the oil circuit: The reason for the blockage of the oil circuit is due to the long-term shutdown of the machine tool and the continuous deposition of dirt in the oil circuit. Blockage of the oil circuit will cause the machine's lubrication system to malfunction, and the lubrication system failure will give rise to many other serious problems. According to statistics, more than 40% of the common failures of machine tools are related to lubrication failures.

 

Failure of the machine tool travel switch: The machine tool travel switch is an important device that limits the mechanical travel range of the machine tool coordinate axis. When the moving part of the machine presses on the transmission part of the travel switch, its internal contact action will switch on, change or break the control circuit. Meet the control requirements of the circuit. The travel switch is generally equipped with a spring. If it is not turned on for a long time, the spring will not be able to return to its original state due to long-term force deformation, the spring will lose its function, and the entire travel switch will also be stuck and fail.

 

Driver, power supply, motherboard and other circuit board failures: In CNC machine tools, the role of the circuit board need not be said. The circuit board has a large number of capacitors. If it is not energized for a long time, these capacitors will age, reduce the capacity, and cause damage to the machine tool circuit. In addition, the main reason for the circuit board failure is that the circuit board will remain in the bottom temperature state for a long time without being used for a long time, which will produce condensed water and cause a short circuit when starting up.

 

Machine tool battery failure: Generally, the CNC system is equipped with a battery. It should be noted that the battery mentioned here is not the power source of the entire equipment, but a device that supplies power to some parts. For example, the system battery is used to save the system parameters; the battery for the absolute position encoder is used to remember the zero position. Even when it is not turned on, the power in these batteries will slowly drain. If the battery is not turned on for a long time, the battery will be drained and the machine data will be lost.

 

Avoidance of CNC machine failure

 

1. For machine tools that have been used for a long time, try not to turn off the machine during the long holiday, and you can take a picture of the emergency stop.

 

2. Regularly check the system fan. If it is contaminated with too much oil, it should be replaced or cleaned up. If it has been used for more than 3 years, it must be replaced.

 

3. Regularly check the hydraulic oil pressure, liquid level and hydraulic impurities in the hydraulic system to ensure the smooth flow of the oil path.

 

4. Regularly clean or lubricate the parts with springs such as the stroke switch, knife arm spring, hydraulic valve spring and so on.

 

5. According to the oily contamination of the drive equipment, clean it regularly.

 

6. Regularly replace the system battery for the machine tool and replace the desiccant for the electrical cabinet of the machine tool, especially before shutting down during a long holiday.

 

7. After the long vacation is over, before restarting, each circuit board of the machine tool should be preheated manually. A hair dryer can be used to heat each circuit board for a few minutes to a little temperature.

The degree of automation of CNC machine tools is very high, with high precision, high efficiency and high adaptability, but its operating efficiency, equipment failure rate, length of service life, etc., to a large extent also depend on the correct use of users And maintenance. A good working environment, good users and maintainers will not only greatly extend trouble-free working time and increase productivity, but also reduce the wear of mechanical parts, avoid unnecessary errors, and greatly reduce the burden on maintenance personnel.