The System Development Of CAK6136 NC Lathe

Open CNC system solving the problem of closed structure in NC system.Open CNC system is not only a tool to machining parts,but also provides users with ways for second-development,such as adding functionalities of image processing or malfunction diagnosis.These functionalities makes NC system more powerful.So it is widely used in NC technology.This paper analysis the structure of "NC embed PC","PC embed NC" and "pure PC".Finally,choosing "pure PC" structure to develop a NC system.A control policy based on"PC+EtherCAT " is used in the process of development,The hardware adopted by this system are BECKHOFF’s motion controller and other components.The software development environment are TwinCAT and C#.According to the real-time requirement,the processing of development is divided into two parts:the functionality of real-time and the non-real time.Real-time functionality is mainly motion control,which require fast response,it is developed in TwinCAT.Automatic mode,MDI mode,Manual mode,returning to reference,decoding and auxiliary functionalities are developed.Non-real time functionality require less for calculate speed,it is finished in C#,which include cutting tool condition monitoring,data transfer and HMI.Cutting tool condition monitoring is the most important work,using tools of three kind of different wear degree in experiment.Collecting the current and vibration of tool,then extract the features and establish the offline mode.The method of PCA is used in the process of features extraction,SVM is used in the process of offline mode establishment.Researching the relationship between spindle’s current and machining parameters.The method of Multiple linear regression is used to establish the relationship.Finally,according to the spindle speed,feed rate,and current,cutting depth can be calculated.ADS(Automation Device Specification)provides C#and TwinCAT with interface for communication,the method of called DLL(Dynamic Link Library)is used to complete data signal processing.In summary,A CNC system with machining and tool condition functions is developed,the CNC system has high integration and high running speed.