| High precision involute gear is an important and widely used basic part in modern machinery industry.Precision gear involute artifact is an indispensable tool for measuring high-precision involute gears.The development of high-precision gear involute artifact is of great significance.In recent years,Wire Electrochemical Micromachining technology has attracted wide attention of scholars because it is not limited by the mechanical properties of materials,high machining precision,good machining quality and so on.The unique machining principle of Wire Electrochemical Micromachining technology can solve the problems which are difficult to solve in traditional machining.According to the research on the forming principle of gear involute,when a plane rolls along a fixed cylinder,the trajectory generated by a straight line on the plane is called the involute of the cylinder,and the speed fluctuation of the rolling motion will not affect the generating accuracy of the involute.In this paper,a horizontal electrode generating Wire Electrochemical Micromachining technology is proposed to machine gear involute template,and a lot of research has been carried out,mainly in the following aspects:1.The machining mechanism of horizontal electrode generating Wire Electrochemical Micromachining technology is studied,a mathematical model of Wire Electrochemical Micromachining technology is established and a electric field simulation is carried out.The formation principle of slit in the process of Wire Electrochemical Micromachining is described and the formation principle of involute profile is further studied.The flow field simulation of the machining gap is carried out,and the effects of reciprocating feed and two-way flushing on the electrolyte renewal in the machining gap are analyzed2.Based on the experimental requirements of horizontal electrode generating electrochemical wire cutting,a horizontal electrode generating electrochemical wire cutting platform is designed and built to ensure that all parts meet the processing requirements;The wire electrode is horizontally fixed in the electrolytic cell and located in the plane of the guide rail.The roller drives the workpiece to do pure rolling on the guide rail.The surface of the guide rail is machined on the outer circle of the roller by grinding technology,which ensures the precision of pure rolling motion and improves the involute generating precision.The supporting numerical control software is compiled to realize the functions of machining control and data acquisition.In order to improve the test efficiency and machining stability and reduce the loss caused by short circuit to the machining system,an automatic tool withdrawal system was established.3.Wire Electrochemical Micromachining experiments were carried out.Firstly,electrochemical characterization experiment were carried out to study the steady-state polarization curves of GCr15 in different electrolytes to provide a basis for electrolyte selection for the next experiments.Then experiments were designed to study the improvement effect of punching solution scheme and feeding scheme on machining stability,and the improvement effect of two-way flushing combined with reciprocating feeding on machining stability was proved.Single-factor experiments were designed to investigate the effects of machining voltage,duty cycle,feed rate,and pulse frequency on machining.Based on the single-factor experiments,response surface experiments were conducted to investigate the optimal combination of parameters for horizontal electrode spreading into electrolytic wire cutting.The best combination of parameters was used to machine a typical structure of an involute sample.A 2 mm thick involute sample blank was machined with an average surface roughness of 2.586 μm and a tooth profile deviation of 17.18 μm.A GIA-rb50 involute sample blank was machined with an involute face thickness of 8 mm,an average surface roughness of 1.435 μm and a tooth profile deviation of 21.23 μm. |
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