Research And Development Of WEDM-HS State Monitoring And Assist-control System

As an important non-traditional machining method, WEDM is widely used in mold manufacturing, difficult-to-machine materials and precision machining of complex parts. WEDM is divided into WEDM-HS and WEDM-LS according to the speed of electrode wire. WEDM-HS invented by Chinese scholars occupies a lot of market share because of its low investment, low cost, and easy-to-operate features. With the development of CNC technology and artificial intelligence technology, mechanical systems, control systems and processing technology of WEDM-HS have been improved a lot, but compared with WEDM-LS, it still has some disadvantages, such as low processing quality, low level of intelligence, easy-to-affected by external factors in processing, and servo feed system having low adaptive capacity, etc.In response to these questions, through a wide range of relevant literature and a great deal of market research, the state monitoring and assist-control systems is developed based on the DK7740 WEDM-HS machine tool. The system is designed to enhance the level of machining intelligence, optimize control system performance, and improve the adaptability of servo-feed system. In this thesis, the main research work is as follows:On the basis of the overall analysis of necessity and feasibility, framework of the system was determined. In hardware, this thesis uses PC to form an open CNC system, and takes parallel port as the communication interface between PC and single-chip controller. In software, select object-oriented Visual C++ as the developing tool, use the modular idea and divide the function of the system reasonably to improve the efficiency of programing.The main monitoring objects of state monitoring sub-system are the wire electrode trajectory and feed rate. This thesis puts forward a new approach to the implementation of the wire electrode track monitoring, by this method, actual track and theoretical track are under the real-time comparing, the key technology of the method is how to set up the theoretical track and ensure its accuracy. With the data decoded from CNC code, plots a bitmap in memory in accordance with the interpolation principle. The bitmap is regarded as the theoretical trajectory. Data collection is finished by using multimedia timer with high timing precision and PC parallel port. Then, the data collected is transformed to the actual trajectory after the program analysis, and the program can achieve the feed rate meanwhile.Assist-control sub-system for controlling the feed rate improves the sampling frequency conversion circuit, and assisted by software, the subsystem reinforces and upgrades the machine tool control system, and it can obviously improve the adaptability of the servo feed system.In order to enrich the function of the system, and make the system user-friendly, this thesis also realizes 3B code decoding, graphics display, analog processing functions. In software debugging stage, a large number of tests were taken to validate and improve the function of the system. The system was also tested by Jinan KETE EDM technology Co., Ltd. and its clients, they all consider the system user-friendly, easy to operate, fully functional, performance-stable, and has good prospects for the popularization and application.