The relation of CNC machine with Servo System
Servo system has been very widely application in the machine tool industry,so the servo system and machine relationship has been very close.As an important function part of CNC machine tools,servo system is an important indicator of system performance.With the development of CNC machine tools,servo control system in the machine tool industry is also constantly improving,and the cooperation between them like a pair of old friends,more and more understanding.
Horizontal CNC machine tools is composed of four parts:the CNC controller,servo drive&servo motor,electrical cabinets and CNC machine tool frame.Its working principle is:through the CNC within configuration dedicated programming software,show the trajectory of processing parts with the coordinates way,and convert these information that can be used to drive the servo motor with a power signal (pulse),control servo motor to drive the corresponding axis to achieve the trajectory.At the same time,the knife is equipped with a CNC turning tool,the corresponding tool is configured by machining processing material,process the materials that fixed on the spindle,then can process the corresponding workpiece.
In the CNC machine tools,servo control system is an indispensable part.Its task is to change NC information into machine tool feed movement,in order to achieve precise control.As the CNC machine tools has high requirements for product processing,so the use of servo control system is critical.
At present,the CNC machine tools using servo control system,the main advantages are: high precision,the accuracy of the servo system is the amount of output to reproduce the amount of input accuracy,including positioning accuracy and contour machining accuracy;stability is good,stability is the system under a given input or external interference,after a short-term adjustment process,can achieve a new or restore to the original balance status,which directly affect the precision and surface roughness of NC machining;fast response,fast response are the important indexes of the dynamic quality of the servo system,it reflects the tracking accuracy of the system;wide speed range,the speed range is up to 0-30m / min;low speed large torque,feed coordinate servo control is constant torque control,in the entire speed range need to maintain this torque,the spindle coordinate servo control at low speed is constant torque control,can provide greater torque,in the high-speed is constant power control,with a large enough output power.
In the machine feed servo is mainly applied permanent magnet synchronous AC servo system,there are three types: analog form,digital form and software form.Analog servo appalication sameness,only receive analog signals,position control is usually achieved by the host computer.Digital servo can achieve a multi-purpose machine,such as speed,torque,position control.It can receive analog instructions and pulse instructions,a variety of parameters are set in a digital way,good stability,has a rich self-diagnosis,alarm function.The software servo is a microprocessor-based digital servo system.It achieves the monitoring program of different kinds control mode,different specification and power servo motor by software.When use,the user can set the code and related data,and it automatically enter working state.With a digital interface,change the working mode,replace motor specifications,just reset the code,so it also known as universal servo.
AC servo has occupied the leading position of the machine feed servo,and with the development of new technologies and constantly improvement,embodied in three aspects:First,electronic devices of the system power drive device develop to high frequency direction,intelligent power module has been popularized and applied;second is based on the mature microprocessor embedded platform technology,will promote the application of advanced control algorithm;third is the promotion of network manufacturing model and the maturity of field bus technology,will make network-based servo control possible.