The fault classification of the servo CNC drilling machine includes deterministic faults, random faults, transmission chain faults, spindle component faults and tool change manipulator faults, etc.; in addition, it must be noted that the voltage must be stable, and a voltage stabilizer must be installed if it is unstable. Next, I will introduce you to the detailed content.
1. Fault classification of servo CNC drilling machine
1. Deterministic failure
Deterministic failure refers to the damage of the hardware in the control system host, or as long as certain conditions are met, the failure of the CNC drilling machine will inevitably occur. This type of failure phenomenon is the most common on CNC drilling machines, but because it has certain rules, it also brings convenience to maintenance. Deterministic failures cannot be recovered. Once it happens，if it is not repaired, the machine tool will not work normally. It will automatically return to normal. However, as long as the root cause of the failure is found, the machine tool can be restored to normal immediately after the repair is completed. Correct use and careful maintenance are important measures to prevent or avoid malfunctions.
2. Random failure
Random failures are accidental failures that occur during the operation of an exponentially controlled machine tool. The cause of this type of failure is subtle, and it is difficult to find its regularity. Therefore, they are often referred to as "soft faults." It is difficult to analyze the causes of random failures and to diagnose failures. Generally speaking, the occurrence of failure is usually related to many factors, such as the installation quality of the components, parameter settings, the quality of the components, imperfect software design and the influence of the working environment. Random failures are recoverable and faulty. After the occurrence, the machine tool can usually be restored to normal by restarting and other measures, but the same failure may occur during operation.
3. Spindle component failure
Due to the use of a speed-regulating motor, the structure of the spindle box of the CNC drilling machine is relatively simple, and the components that are prone to failure are the automatic clamping mechanism and the automatic speed-regulating device inside the spindle. In order to ensure that the tool holder will not loosen during work or power failure, the automatic clamping device adopts spring clamping and is equipped with a travel switch to send a clamping or loosening signal. If the tool cannot be loosened after clamping, please consider adjusting the pressure of the hydraulic cylinder for loosening the knife and the stroke switch device, or adjusting the nut on the disc spring to reduce the spring compression. In addition, the problems of spindle heating and spindle box noise cannot be ignored.
4. Transmission chain failure
In the feed drive system of CNC drilling machines, ball screw pairs, hydraulic screw nut pairs, rolling guides, hydraulic guides and plastic guides are usually used. Therefore, there is a fault in the feed transmission chain, which is mainly reflected in the decline in the quality of motion. If the mechanical parts are not moved to the specified position, the operation is interrupted, the positioning accuracy is reduced, the gap is increased, the crawling, the bearing noise becomes larger (after a collision), etc.
5. Failure of automatic tool changer
The failure of the automatic tool changer is mainly manifested in: the tool magazine movement failure, excessive positioning error, unstable clamping of the tool holder by the manipulator, and large movement error of the manipulator. When the fault is serious, the tool change action will be stuck, forcing the machine tool to stop working.
6. Movement failure of the tool magazine
If the mechanical connection between the motor shaft and the worm shaft is loose or the mechanical connection is too tight, the tool magazine cannot be rotated. At this time, the screws on the coupling must be tightened. If the tool magazine does not rotate in the original position, it is caused by motor rotation failure or transmission error. If the current tool sleeve cannot clamp the tool, you need to adjust the adjustment screw on the tool sleeve, press the spring, and then tighten the clamping pin. When the upper and lower positions of the knife sleeve are not correct, check the position of the dial or the installation and adjustment of the limit switch.
7. Malfunction of the tool change manipulator
If the tool change manipulator is not tight and the knife falls, please adjust the clamping jaw spring to increase the pressure, or replace the clamping pin of the manipulator. If the tool does not open after clamping, adjust the nut behind the lock spring so that the maximum load does not exceed the rated value. If the tool is dropped during the tool change, it is because the headstock does not return to the tool change point or the tool change point drifts during the tool change. The head stock should be operated again to return it to the tool change position, and the tool point should be replaced.
8. The pressure switch failure of each axis stroke position
On the CNC drilling machine, in order to ensure the reliability of automation, a large number of travel switches are used to detect the movement position. After a long-term operation of the machine tool, the motion characteristics of the moving parts change, and the reliability of the limit switch pressing device and the quality characteristics of the limit switch itself have a great influence on the performance of the whole machine. Usually, it is necessary to check and replace the stroke turn-on time, so that the influence of bad switches on the machine tool can be eliminated.
9. Auxiliary equipment failure
Hydraulic system-The hydraulic pump should use a variable pump to reduce the heat of the hydraulic system. The filter installed in the fuel tank should be cleaned regularly with gasoline or ultrasonic vibration. The common faults are mainly pumping wear, cracks and mechanical damage. At this time, overhaul or replacement of parts is usually required.
10.Common troubleshooting methods for CNC drilling machines
Because the faults of CNC drilling machines are more complicated, and the self-diagnostic ability of the CNC system cannot test all the components of the system, this is usually an alarm number, indicating many reasons for the fault, making it difficult for people to get started.