Fault Analysis and Situation Diagnosis of NC Thread Rolling Machine Servo System
Abstract: As an important industrial automation control system, the servo system of NC thread rolling machine has complex components and various fault forms, which put forward higher requirements for fault diagnosis and analysis capabilities. This paper introduces the operation principle of servo system and its fault analysis and situation diagnosis.
Key words: Servo system, NC thread rolling machine, fault analysis and diagnosis
1 Introduction
The thread rolling machine is used to mechanically increase the size of the root to the range of specification requirements. The traditional thread rolling machine is a mechanical machine. It adopts the method of manually entering parameters to adjust the machine according to the product. With the development of modern automation technology, NC thread rolling machines have been widely used, especially servo thread rolling machines, which can greatly save manpower and improve product accuracy and stability.
The main components of NC thread rolling machine servo system are servo motor, speed reducer, synchronous belt and corresponding encoder. Similarly, there are many fault forms and causes of servo system, and the process of fault diagnosis is also vary. This paper introduces the principle of servo system and puts forward the fault analysis and situation diagnosis method of the servo system for the reference of the fault analysis and incidence of the servo thread rolling machine operators.
2 Principles of servo system
The servo system of NC thread rolling machine is composed of servo motor, speed reducer, synchronous belt and corresponding encoder. Driven by the servo motor, the speed reducer drives the rolling shaft and rib rollers of the thread rolling machine through the synchronous belt to realize the thread rolling effect. The encoder is the sensor of the servo motor, which can detect and feed back the actual speed and position of the servo motor to the control system.
The servo system of the NC thread rolling machine can pass the number of revolutions of the rolling shaft to realize the control of the rolling force, rolling speed, rolling length and other parameters. According to the rolling parameters and product requirements, the corresponding numeral quantity is entered into the control system, the corresponding control and adjustment commands are generated, and the servo motor and speed reducer are driven to complete the control and adjustment of the thread rolling process.
3 NC thread rolling machine servo system fault analysis and situation diagnosis
The servo system of NC thread rolling machine mainly has two parts: servo motor and speed reducer. Due to the complex structure and wide range of applications, it often fails in working. Before fault analysis, it is necessary to understand the operating parameters and relevant working specifications of the servo system.
3.1 Fault Analysis of Servo Motor
The faults of servo motor mainly include (1) Alarm blinking: in the electric drive panel, the alarm light blinks, and the alarm sound alarm is normal, which is mainly caused by the over-temperature shutdown of the motor. (2) Unstable speed of drive motor: increasing the acceleration/deceleration time can eliminate the phenomenon that the response speed of electric drive is too slow. (3) Strange sound: Generally, it is caused by bearing damage or lacking of lubrication oil. It is necessary to check whether there is lubrication oil in the servo motor bearing housing, and whether the lubrication oil is suitable for the servo motor. If necessary, add or replace the lubrication oil to the required capacity. (4) Vibration: If the vibration is severe and the cause is unclear, the vibration of the motor bearing can be checked. In normal operation, the vibration of the motor bearing is small, and it is different when the bearing is damaged. It should be checked with a vibration radar.
3.2 Speed Reducer Fault Analysis
There are mainly three common faults of speed reducer: (1) Too much noise: Generally, the sound is caused by the damage of bearing, gear and sliping belt of speed reducer. It is necessary to open up parts to check the condition of parts such as bearings, gears and belts. (2) The speed reducer cannot output power normally: it is common in the process of running in or the temperature change of the speed reducer. It is necessary to check the temperature and speed change of the speed reducer in real-time. If it is caused by external environment, the fault is easy to solve. (3) Low efficiency and large temperature rise: It is mostly caused by poor lubrication and poor clearance of speed reducer. It is necessary to check and adjust the clearance of speed reducer regularly, and replace the lubrication oil.
3.3 Fault Indication and Troubleshooting of Servo System
In order to accurately diagnose the fault of servo system of NC thread rolling machine, it is necessary to understand the fault information from the fault indicator. (1) The control panel of the servo system displays the fault when the fault occurred, the detailed fault code and the corresponding fault phenomenon. (2) Check the running current of the servo motor and the abnormality of the speed reducer. (3) According to the fault phenomenon and the fault information displayed by the control panel, check the corresponding parts for fault. If the fault is not clear, try to change the spare parts.
4 Conclusion
The servo system of NC thread rolling machine is composed of servo motor, speed reducer, synchronous belt and encoder. The process of fault analysis and situation diagnosis of servo system is very important and comprehensive, which requires operators to have a correct understanding of the servo system, the ability to analyze and diagnose the fault information accurately, and to maintain the servo system in time. This paper introduces the principles and fault diagnosis methods of servo system comprehensively. It is hoped that this paper can help operators know more about the servo system of NC thread rolling machine and master the maintenance measures of NC thread rolling machine servo system.
