Research On Key Technologies And Software Development Of Small CNC System

With the vigorous development of manufacturing industry,the functions of CNC systems are also increasing.At present,CNC system has achieved many advanced functions,but with it comes the complexity of its structure and the increase of production costs.In some small and medium-sized manufacturing industries,the introduction of a complete CNC system can not only waste functions but also cost too much.Small CNC system has the characteristics of simple structure,easy operation and low cost.Therefore,small CNC system is taken as the research object in this thesis,some key technologies in CNC machining is studied,and corresponding software system is developed.Tool path feeding is one of the most critical technologies in CNC machining.Specific trajectory feeding is performed by driving the motor.Based on the digital instructions and pulse instructions of the driving motor,the interpolation algorithms of the straight line,arc and NURBS curves of the two instructions are studied,and the interpolation algorithms are combined to design.Eight kinds of algorithm selection modes are derived.Different interpolation modes can be selected according to different actual conditions.Aiming at the impact fluctuation caused by tool path feeding,the adaptive speed forwardlooking control algorithm is studied in this thesis.According to the curvature of the feed trajectory curve,the position of the speed sensitive point is determined adaptively,and the constraint condition of the feed speed of the high curvature point is obtained.The position of the deceleration point is obtained by using speed control algorithm.In the part of speed control algorithm research,the traditional S-type acceleration and deceleration algorithm is designed to speed up the process,and the simulation experiment is carried out to achieve the effect of acceleration and deceleration process.On the basis of the above theoretical research,small CNC software is designed and developed in this thesis.Using C++ programming language and MFC function class library under Visual Studio 2015 software,the NC function interface is designed.Taking a function curve as an example,the multi-mode interpolation algorithm and adaptive speed forwardlooking control algorithm are applied.Four of them are selected for experimental design,and the corresponding interpolation curves and speed curves are obtained.The auxiliary monitoring module is designed.Using TIA Portal V14 software programming platform and SIMATIC S7-1200 PLC,the tool temperature detection module,tool change module and alarm module are designed.The CNC monitoring interface is designed based on SIMATIC WINCC and connected with PLC by setting IP address.The S7-PLCSIM V14 simulator is used to simulate and verify the system.The auxiliary control function of the small CNC system is realized,and the running state of the system can be monitored in real time.