Interference and Prevention of CNC System
Abstract： CNC system is one of the most important technologies in modern industry, while the interference of the system affects its stable operation. This article will make an analysis of the common interference and the potential reasons for the interference of CNC system, and take some common prevention measures.
Keywords: CNC system; interference; prevention
1 Introduction
CNC system is a modern advanced control method which widely used in machine manufacturing industry. With its abnormal control technology, it has provided correct control commands to processing machining centers, with the assistance of corresponding computer control system and software program, it can realize high precision, high speed, economical and efficient production. However, during the operation of the equipment using CNC system, various interference will occur, which will affect its normal operation, so the prevention of interference become a top priority.
2 Common Interference of CNC System
2.1 Magnetic Induction Interference
Magnetic induction interference refers to the interference caused by the current or voltage of AC or DC in the power grid as well as the external coil to the CNC system of the equipment. The common harmful magnetic induction interference often comes from the motor, transformer, welding machine, high-voltage line, public power and switch on and off. The magnetic induction interference of the CNC system is easy to cause the miss operation of the power circuit, time deviation and the increase of the ground resistance.
2.2 Electrostatic Interference
Electrostatic interference is an interference form that is generated due to the movement of charge to the electronic components and the rapid change of potential in the system. In the CNC system, electrostatic radiation come mostly from static electricity, static charge induction and static charge discharge. It has the characteristics of strong directivity and strong frequency.
2.3 Radio Frequency Interference
Radio frequency interference is an interference form generated by the working of high-frequency circuit and the interference caused by high-frequency wave generated by the electromagnetic wave itself. In terms of CNC system, it is caused by the emissions of high-frequency devices such as radio waves, radar waves, microwave ovens and communication devices.
3 Causes of CNC System Interference
3.1 Inadequate grounding
Grounding or earthing, is the most basic and effective maintenance to eliminate interference. When the static potential equals to zero, the static electricity cannot be induced again and cannot interfere with the CNC system. Therefore, if the grounding is not proper, the electrostatic interference will be present in the CNC system.
3.2 Excessive electrical network noise
Electrical network noise is the noise generated by the high frequency working of the electromagnetic field. When it passes through the long distances, it will cause high frequency and voltage noise in the CNC system. The electrical network noises can be generated by motors, welding machines, induction cookers, fluorescent lamps and electronic ballasts. When the interference of electrical noise is strong enough, its possible for the CNC system to be affected.
3.3 Radio frequency interference
Radio frequency (RF) interference can be generated from a variety of sources, including communication devices, such as mobile phone base stations, radio and TV transmits, as well as equipment that utilizes RF technologies, such as WiFi routers, Bluetooth and microwave ovens. These devices have unexpected powerful electromagnetic radiationwhich can introduce significant noise into a CNC system if left unchecked.
4 Prevention of CNC System Interference
4.1 Grounding
Grounding or earthing should be one of the most important maintenance operations when using CNC system, it is a measure of safety, common and effective way to eliminate interference. To ensure the link between the power and neutral line is reliable and correct grounding, no matter what type of grounding is used, check it regularly and ensure its fastening during maintenance.
4.2 Shielding
Shielding is another effective measure to protect the control system from interference. Shielding can be used to protect the equipment from interference caused by external magnetic and electrostatic interference. The shielding room should be made of good conductive material and the surface should be processed into a smooth ground state to reduce the pollution of electrostatic interference.
4.3 Filter and Decoupling
Using filter and decoupling device can effectively reduce the noise voltage and eliminate the low frequency and high frequency interference. Using ferrite cores to enhance the filter effect can effectively suppress the interference signal to the CNC system.
5 Conclusion
Interference has become one of major problems for CNC system in recent years, it can pose a serious threat to the stable function of the CNC system. This article analyzes the common interference and potential causes of the CNC system, and takes some common prevention measures. It is hoped that these measures could help CNC system maintain its correct and stable operation.
