Research On Wire Electrode Constant Tension Control Of WEDM-HS

With the rapid development of technology and modern industry, materials of highhardness, high strength, high toughness and high brittleness are used more and morewidely. The parts with special complex shapes have found increasingly wide utilization,and the requirements of high quality and accuracy surface are more and more strict.WEDM (Wire Electrical Discharge Machining), which works as an important machiningmethod of non-traditional machining, has played a great role in mold and aerospaceindustry. Because of the high speed of wire transport, the wire tension of WEDM-HSchanges greatly which will cause lower accuracy and quality of the works. Therefore,researching on the system of wire tension control has great significance to improve themachining quality and lower the costs of some high precise parts.In this thesis, the factors which influence the wire tension are investigated firstly.The factors of preliminary tension and wire transport speed are studied throughexperiments. Then the span distance between the two wheels which influences the wirevibration and tension are analyzed by the ANSYS software.The structure of the tension control system is designed in this thesis. To guaranteethe accuracy, stiffness, stability and reliability of the system, the design and optimizationof the parts and components are carried out. In addition, the dynamic characteristic of thesystem is analyzed to ensure good response characteristics.The control software is designed in this thesis, which includes the interface of thePC program and the control program of the DSP. The interface of the PC is used to sendthe commands to DSP and monitor the status of the wire tension. The modularized designmethod is used in the DSP program. The PID control strategy is used to realize the wiretension real-time and effective control.Finally, debugging and validation of the system are carried out. To ascertain the bestcontrol effect, the debugging of the system is completed. The actual wire tension underthe certain aim of the control system is studied. Besides, the condition of wire tensionwith tension control system is researched under different wire transport speed and targettension. In addition, the surface quality under different circumstances is researched.Through the researches above, we can draw a conclusion that the wire tension controlsystem is effective to realize the relatively stable wire tension and better machiningquality.