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How to maintain and maintain CNC machine tools in use?

Posted by: Chris Na 2021-05-26 Comments Off on How to maintain and maintain CNC machine tools in use?

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 maintenance content and rules also have their own characteristics. Specifically, according to the type, model and actual use of the machine tool, and with reference to the requirements of the machine tool manual, the necessary regular and graded maintenance system should be formulated and established. The following are some common and general daily maintenance points.

2.1 Maintenance of CNC system

1) Strictly abide by the operating procedures and daily maintenance system

2) Open the doors of CNC cabinets and power cabinets as little as possible

There are generally oil mist, dust and even metal powder in the air in the machining workshop. Once they fall on the circuit board or electronic device in the CNC system, it is easy to cause the insulation resistance between the components to drop, and even cause the components and the circuit board to be damaged. . In the summer, in order to make the numerical control system work for a long time, some users open the door of the numerical control cabinet to dissipate heat. This is an extremely undesirable method, which will eventually lead to accelerated damage to the numerical control system.

3) Regularly clean the cooling and ventilation system of the CNC cabinet

It should be checked whether each cooling fan on the CNC cabinet works normally. Check whether the air duct filter is clogged every six months or every quarter. If too much dust accumulates on the filter and it is not cleaned in time, the temperature in the CNC cabinet will be too high.

4) Regular maintenance of the input/output devices of the numerical control system

Most of the CNC machine tools produced before the 1980s were equipped with photoelectric paper tape readers. If the tape reading part is contaminated, it will cause errors in reading the information. For this reason, the photoelectric reader must be maintained in accordance with regulations.

5) Regular inspection and replacement of DC motor brushes

The excessive wear of the brushes of the DC motor will affect the performance of the motor and even cause damage to the motor. For this reason, the motor brushes should be regularly inspected and replaced. CNC lathes, CNC milling machines, machining centers, etc. should be inspected once a year.

6) Regularly replace the storage battery

Generally, the CMOSRAM storage device is equipped with a rechargeable battery maintenance circuit in the CNC system to ensure that the memory content of the system can be maintained during the period when the system is not powered. Under normal circumstances, even if it has not failed, it should be replaced once a year to ensure that the system works normally. The battery replacement should be carried out under the power supply state of the CNC system to prevent the information in the RAM from being lost during the replacement.

7) Maintenance of spare circuit board

When the spare printed circuit board is not used for a long time, it should be regularly installed in the CNC system and run for a period of time to prevent damage.

2.2 Maintenance of mechanical parts

1) Maintenance of the main drive chain

Regularly adjust the tightness of the spindle drive belt to prevent loss of rotation caused by belt slippage; check the constant temperature oil tank for spindle lubrication, adjust the temperature range, replenish the oil in time, and clean the filter; the tool clamping device in the spindle is used for a long time , There will be a gap, which will affect the clamping of the tool, and the displacement of the hydraulic cylinder piston must be adjusted in time.

2) Maintenance of ball screw thread pair

Regularly check and adjust the axial clearance of the screw thread pair to ensure the reverse transmission accuracy and axial rigidity; regularly check whether the connection between the screw and the bed is loose; the screw protection device should be replaced in time to prevent dust or Chips enter.

3) Maintenance of tool magazine and tool change manipulator

It is strictly forbidden to load overweight and overlong tools into the tool magazine to avoid tool loss or collisions between the tool and the workpiece or fixture when the manipulator changes the tool; always check whether the zero return position of the tool magazine is correct, and check whether the machine tool spindle returns to the tool change point. In place, and adjust in time; when starting up, the tool magazine and manipulator should be run dry, check whether each part is working normally, especially whether each travel switch and solenoid valve can operate normally; check whether the tool is locked reliably on the manipulator, and it is not found It should be handled in time if it is normal.

2.3 Maintenance of hydraulic and pneumatic systems

Regularly clean or replace the filters or sub-filters of the lubrication, hydraulic and pneumatic systems; regularly check the oil quality of the hydraulic system and replace the hydraulic oil; regularly drain the air filter of the pneumatic system;

2.4 Maintenance of machine accuracy

Regular inspection and correction of machine tool level and mechanical accuracy. There are two methods for correcting mechanical accuracy: soft and hard. The soft method is mainly through system parameter compensation, such as screw backlash compensation, fixed-point compensation of each coordinate positioning accuracy, machine tool reference point position correction, etc.; hard methods are generally carried out when the machine tool is overhauled, such as rail repair scraping, ball rolling The screw nut pair is pre-tightened to adjust the backlash, etc.