What are the common faults and troubleshooting methods for CNC machine tool servo systems?
The servo system is the link between the numerical control device and the machine host.It is used to receive the feed pulse or feed displacement information from the CNC device interpolator.After a certain signal conversion and voltage and power amplification,the servo motor drives the transmission mechanism.Finally,it is converted into a linear displacement or a rotary displacement of the machine table relative to the tool.
In order to improve the performance of CNC machine tools,high requirements are placed on the feed servo system for machine tools.Since the machining tasks performed by various CNC machine tools are different,the requirements for the feed servo system are also different.The following are common faults in the servo system.
1,overtravel.When the feed motion exceeds the software limit set by the software or the hardware limit set by the limit switch,an overtravel alarm will occur,and the alarm content will be displayed on the CRT.According to the CNC system manual,the alarm can be eliminated.Fault,cancel the alarm.
2,overload.When the load of the feed motion is too large,frequent positive and negative movements,and poor lubrication of the transmission chain,an overload alarm will be caused.Alarm information such as servo motor overload,overheat or overcurrent is usually displayed on the CRT.At the same time,on the feed drive unit in the power cabinet,the indicator light or the digital tube will prompt the drive unit to overload,over current and other information.
3.Inciting.Agitation occurs during feeding:
1 The speed measurement signal is unstable,such as the speed measuring device failure,the speed feedback signal interference,etc.;
2 The speed control signal is unstable or interfered with;
3 The terminal is not in good contact,such as loose screws.
When the turbulence occurs in the commutation moment of the forward direction and the reverse motion,it is generally caused by the backlash of the feed chain or the servo system gain being too large.
4.Crawl.When it occurs in the starting acceleration section or low-speed feed,it is generally caused by factors such as poor lubrication state of the feed transmission chain,low servo system gain,and excessive load.In particular,the coupling between the servo motor and the ball screw is not synchronized with the rotation of the servo motor due to loose coupling or defects in the coupling itself,such as cracks.Give the movement a flickering and creeping phenomenon.
5.The machine tool vibrates.When the machine is running at high speed,vibration may occur and an overcurrent alarm will occur.Machine vibration problems are generally speed problems,so you should look for the speed loop;and the entire adjustment process of the machine speed is done by the speed regulator,that is,all speed-related problems should be found in the speed regulator,so the vibration problem Look for the speed regulator.Mainly from the given signal,feedback signal and speed regulator itself to find faults.
The above are the problems that often occur in our machine tool servo system and the corresponding troubleshooting methods.When the above failure occurs in the servo system,we can solve it ourselves to ensure the efficiency of CNC lathe processing.