Common failures of CNC machine tools

1.destructive failure.

1) the fault will cause damage to the machine tool and the operator, resulting in machine tool damage or personal injury.

2) some destructive faults are caused by people.

3) the maintenance personnel shall not allow the fault to recur when making fault diagnosis. They can only analyze and troubleshoot the fault after inspection according to the introduction of on-site personnel.

4) the troubleshooting of such faults is technically difficult and has certain risks, so the maintenance personnel should be very cautious.

(2) non-destructive failure.

1) most of the faults are of this kind, which can be eliminated by "clearing zero".

2) maintenance personnel can reproduce such failures and analyze and judge the phenomena.

2. According to the fault nature of CNC machine tools:

(1) systemic failure.Usually refers to as long as meet certain conditions or more than a set limit, the work of CNC machine tools will inevitably occur.This kind of fault phenomenon is very common.For example, when the pressure value of the hydraulic system drops to a certain set parameter with the blocking of the hydraulic circuit filter, the hydraulic alarm will inevitably occur and the system will be cut off and shut down.Another example: lubrication system because of pipeline leakage caused by the oil standard to fall to the use of the limit value will inevitably occur liquid level alarm machine stop.Another example: machine tool machining because the cutting amount is too large to reach a certain limit will inevitably occur overload or overtemperature alarm, resulting in rapid shutdown of the system.

(2) random failure.Usually is the index control machine tool in the same condition when the operation only happens once or twice the fault.

Some people call this a "soft fault", because it only happens once or twice under the same conditions.Therefore, the cause analysis and fault diagnosis of random faults are much more difficult than other faults.Generally speaking, the occurrence of such faults is often related to installation quality, component arrangement, parameter setting, component quality, operational errors and improper maintenance, as well as the impact of the work environment and other factors.For example, the connector and the connecting component are not locked due to negligence, the components on the printed circuit board are loose and deformed or the solder joint is broken, the relay contacts, all kinds of switch contacts are corroded by pollution and the dc motor carbon brush is not good and the contact is not reliable.In addition, the working environment temperature is too high or too low, the humidity is too high, the power supply fluctuation and the mechanical vibration, the harmful dust and the gas pollution and other reasons can cause this kind of accidental failure.Therefore, strengthen the maintenance inspection of the numerical control system, ensure the sealing of the electrical box door, strictly prevent the invasion of industrial dust and harmful gas, etc., are as far as possible to avoid the occurrence of such trouble.

3. According to the fault parts of CNC machine tools:

(1) host failure.The main part of CNC machine tools, including machinery, lubrication, cooling, chip removal, hydraulic, pneumatic and protection devices.Common faults of the main engine include mechanical transmission failure or excessive friction of the guide rail caused by improper mechanical installation, debugging and operation.Its performance is the transmission noise, the processing accuracy is poor, the movement has the resistance.For example: the flexible coupling of the axial transmission chain is loose, the gear, the lead screw and the bearing are short of oil, the guide rail inserts are not adjusted properly, the guide rail is not well lubricated and the system parameters are not set properly.In particular, attention should be paid to the machine tool parts marked oil injection point (oil injection hole) must be timed, quantitative injection of lubricating oil (agent), which is the machine tool transmission chain to ensure the normal operation.

In addition, hydraulic, lubrication and pneumatic system failure phenomenon is mainly pipe block and poor sealing, therefore, CNC machine tools should strengthen the governance and eradicate the occurrence of "three leakage" phenomenon.

(2) electrical fault.Electrical faults are divided into weak current faults and strong current faults: weak current mainly refers to CNC devices, PLC controllers, CRT displays, servo units, input and output devices and other electronic circuits. This part is divided into hardware faults and software faults.

Hardware failure mainly refers to the failure of integrated circuit chips, discrete components, connectors and external connection components on the printed circuit board of the above devices.

Common software failures include: machining program error, system program and parameter change or loss, computer calculation error.

The strong current part is to point to circuit breaker, contactor, relay, switch, fuse, power transformer, motor, electromagnet, travel switch and other electrical components and their circuit composition, this part of the fault is particularly common, must cause enough attention.