Precautions when the machine tool is shut down for a long time


Good maintenance can keep the machining accuracy of the machine tool in the best state, prolong 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 state and improve production efficiency and processing effect.

 

Maintenance of CNC machine tool shutdown

There are many types of CNC machine tools, and various 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. Specifically, the necessary 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 instruction manual. Below are some common general maintenance points.

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

2. Anti-rust treatment: clean and wipe the worktable and apply anti-rust oil; the machine tool runs at a slow speed for one hour to lubricate the line rail; whether the cutting fluid needs to be replaced, give priority to the anti-rust treatment, and add it when the machine tool starts to work cutting fluid.

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

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

5. Anti-rodent treatment for machine tools: The machine tool is also treated against rodents to prevent rats from biting off the wires.

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Commissioning of CNC machine tools

CNC machine tool is a kind of mechatronics equipment with high technical content. It is very critical to start up and debug in the correct way, which largely determines whether the CNC machine tool can play normal economic benefits and its own service life.

Check before starting the machine: 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 product has deteriorated.

Start up step by step: the power supply voltage of the machine tool must be checked before starting up, and the power switch of the machine tool can be turned on only after the main power switch is turned on for about 10 minutes after the voltage is stable, and then other power switches in the electric box are turned on to check whether the voltage is phase-deficient or not. If it is too low, turn on the power of the machine tool under no abnormal condition, and observe whether there is any abnormal phenomenon and whether there is air leakage. If there is no alarm when the machine is turned on, do not perform any action, and leave the electrical components energized for 30 minutes.

Slow movement: Check whether there is interference, move the machine tool with the handwheel in the whole process, pay attention to whether there is any abnormal phenomenon, and then perform the step of returning to the origin.

Machine tool break-in: Automatically run the machine tool at slow speed for a long time, and rotate the spindle at low speed.

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Common faults of CNC machine tools

Fan failure: The fan in the machine tool can dissipate heat and cool down the core equipment, effectively avoiding overheating and damage to the equipment. At the end of long holidays, machine tool fans often “strike” due to oil contamination. When the machine tool is stopped, the fan inside the machine tool will also stop. At this time, the oil in the machine tool will flow into the bearing of the fan, causing the circuit of the fan to short-circuit, and the fan will alarm or fail to start when it is turned on again. The longer the downtime, the greater the risk. 5 axis cnc machining services

Seal failure: Seals must be used in both hydraulic and pneumatic devices of machine tools to ensure the airtightness of the device and maintain its normal pressure supply. Seals are generally rubber products, which are prone to aging, especially during long holidays, when the machine tool is not started for a long time and the hydraulic pressure does not flow, which is more likely to cause the hardening of the seals, resulting in oil leakage of the machine tool, insufficient pressure provided by the hydraulic device and other problems.

Blockage of the oil circuit: The reason for the blockage of the oil circuit is that the machine tool has been shut down for a long time and the dirt in the oil circuit is continuously deposited. Blockage of the oil circuit will cause the lubrication system of the machine tool to fail, and the failure of the lubrication system will lead to many other serious problems. According to statistics, more than 40% of all common machine tool failures are related to lubrication failures.

The machine tool travel switch fails: The machine tool travel switch is an important device that limits the mechanical travel range of the machine tool coordinate axis. When the moving parts of the machine are pressed against the transmission parts of the travel switch, its internal contacts act to connect, transform or break the control circuit. To 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 stress and deformation, the spring will lose its function, and the entire travel switch will also be stuck and invalid.

Failure of circuit boards such as drives, power supplies, and motherboards: In CNC machine tools, the role of circuit boards need not be said much. The circuit board has a large number of capacitors. If the power 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 failure of the circuit board is that if the circuit board is not used for a long time, the circuit board will be in a low temperature state for a long time, which will generate condensation water and cause a short circuit when it is turned on.

The machine tool battery fails: Generally, the CNC system is equipped with a battery. It should be noted that the battery mentioned here is not the power supply of the whole equipment, but a device that supplies power to some parts. For example, the system battery is used to save the system parameters; the battery used for the absolute position encoder is used to remember the zero position. The charge in these batteries slowly drains even when not powered on. If the machine is not turned on for a long time, it is easy to make the battery dead, resulting in the loss of machine data. 5 axis machining

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Avoidance of failures of CNC machine tools

1. For machine tools that have been used for a long time, try not to shut down 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. If it has been used for more than 3a, 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 circuit.

4. Regularly clean or lubricate the components with springs such as the process switch, knife arm spring, hydraulic valve spring, etc.

5. According to the situation that the drive equipment is contaminated with oil, it should be cleaned regularly.

6. Regularly replace the system battery for the machine tool and replace the desiccant for the machine tool electrical cabinet, especially before the shutdown for a long holiday, this step should not be forgotten.

7. After the long holiday, before restarting the machine, it is necessary to manually preheat each circuit board of the machine tool. You can use a hair dryer to heat each circuit board for a few minutes, and it is enough to have a little temperature .5 axis machining center

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


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