| Equipment manufacturing is a strategic industry, which provides technology equipments for the national economy. Presently, the trends of the equipment manufacturing, especially the advanced equipment manufacturing, are intelligent, flexible and green. Electrical Discharge Milling (ED-Milling) is an important technique in the scope of Electrical Discharge Machining (EDM). It uses the simple electrode as tool and the electrode moves like the traditional mill. The workpieces are machined by this technique to get the required shape by means of the sparks between the electrode and workpieces. On one side, like other EDM method, ED-Milling machining has no restrictions in hardness, strengthness and toughness of workpiece and has the wide range of application. And on the other side, ED-Milling has the feature of mutil axis linkage motion for generating machine. ED-Milling can process long and deep narrow groove that is difficult for tradiational die EDM to machine. It makes the electrode wear compensation to be easier for using the simple electrode. Rotational electrode improves the discharge conditions, make the processing more stable. The small processing area effectively reduces the capacitor effect and better qulitily of surface could be got. Because of its outstanding ability in the machining of middle and small size workpieces with 3D, ED-Milling has become a research focuse in the range of EDM in the world.It is generally believed that EDM must work in insualtive medium, like kerosene, saponification solution and deionized water, etc. This is the nesseary condition for generation of the pulse electrical discharge. Water is weak electrolyte. It is thought that water is not suitable to be used as dielectric for EDM. But in high speed EDM drilling, water is used as dielectric and jetted into discharge gap through the tube electrode with high speed and pressure in the processing. Inspired by this, ED-Milling machine tool with rotational electrode with inner jetted dielectrode has been developed in this dissertation and some key technologies of this method have been studied.Fistlly, conversation of electrical discharge energy in the discharge gap and its transfer between anode and cathode have been theoretical studied. The possibility of using water as dielectric has been demonstrated by through theoretical analysis and flow field software simulation. The reason for using positive polarity machining when using the water as dielectric in ED-Milling has been analyzed. The impacts of water with high velocity and pressure on micro procedure of electrical discharge and removal and thrown of material also have been deeply researched.After analyzing of requirements on hardware and software, a ED-Milling machine system has been designed and developed. The system includes mechanical part and electrical control part. The mechanical part is composed of machine body components, work table components, column components, main axis components, rotational head and dielectric supplier. Electric control part is composed of computer, pulse power supplier, motion control system, servo detection and control system, etc. The softwear of the system is divided into three part, DSP servo control software, PMAC motion control software and PC NC software, based on requirements of real-time for their functions.Servo control system is an important part in EDM system. In this dissertation, a servo motion control system based on PMAC and DSP has been constructed. By using of high accuracy of interpolation motion control function of PMAC, the tactics of switching between positive and negative motion track has been proposed to realize quickly and accurately backward motion when short appearing in the processing. The realization of adjusting of motion velocity which relies on gap status is based on self-adaptive theory and time base function in PMAC.According to the ED-Milling using rotational tube electrode, inner jetted dieelctrode and laminated machining method, the effections of several processing parameters and discharge status accumulated time on electrode wear were deeply analyzed. Then, an electrode wear prediction model based on Radial Basis Function (RBF) neural network was constructed. A tactics with fix length detection and continuously compensation for electrode wear was proposed. The CNC software uses MATLAB engine technique to realize the detection and compensation the electrode wear on line by throuth the processed parameters and accumulated discharge status time in the procedure of machining.At last, for getting the technological rules of ED-Milling with rotational electrode and inner jetted dielectric, machining experiments were carried out by using the ED-Milling machine tool developed in the dissertation. The effecion of several electrical parameters on discharge gap and processed workpiece surface routhness and effection of dielectrode supplied method with rotational tube electrode and inner jetted on processing were analyzed. The contrasting experiments between the electrode wear compensation tactics proposed in this dissertation with other tacticses to confirm the validity. Finally, the experiments of machining 3D cavities show the excellent machining performance and wide practicability of the ED-Milling machining equipment.
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