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Research on the Cutting Accuracy and Surface Quality of Multi-cutting in HSWEDM

Author: ZhangYan
Tutor: LiuZhiDong
School: Nanjing University of Aeronautics and Astronautics
Course: Mechanical Manufacturing and Automation
Keywords: High-speed wire Repeatedly cutting The amount of correction Finite Element Analysis Temperature field Surface quality
CLC: TG484
Type: Master's thesis
Year: 2010
Downloads: 103
Quote: 2
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Abstract

High-speed wire WEDM cost-effective and low operation cost advantage has been widely applied in the field of machining, but cutting accuracy in the presence of several cutting instability and poor surface quality problems have been restricting The development of the technology, but also the impact of its application in the field of finishing. High-speed wire EDM the multiple cutting process problems: First, whether the wire compound under the conditions of the working fluid gap discharge directly affected multiple cutting accuracy to the stability of this key issue; Second, due to the multiple cutting The actual correction amount directly affect multiple cutting absolute dimensional accuracy, the actual correction amount, with the theoretical relationship of the correction amount to be clear; Again, due to the inevitably exist in the working fluid in the electrolyte, electrolytic corrosion layer appears repeatedly cutting surface, direct impact on the life of the workpiece; Finally, due to the limitations of the current pulse power, repeatedly cutting surface roughness has not been significantly reduced, compared with the low speed to go wire EDM wire cutting large gap still exists. The emergence of these issues have a direct impact on the application of high-speed WEDM wire bed in the finishing field. In response to these problems, the main work of this paper are as follows: 1) composite working fluid under the conditions of high-speed wire EDM wire cutting discharge mechanism, through theoretical analysis and experiments prove that the discharge process and not the passive film appear electrode wire discharge gap between the workpiece and to lay the foundation for further study of the follow-up of several cutting process. 2) composite working fluid under the conditions of high-speed wire EDM repeatedly cutting the impact of the actual amount of correction factors and the law, pointed out that the electrical parameters of the pulse width, processing current limit stick electrode wire span, actual feedrate , wire-speed non-electric parameters have a greater impact on the actual amount of correction, and the tension of the wire between the veins on the actual amount of correction is not obvious, and process trials indicate that the first comprehensive consideration of the last cutting discharge gap differences case repeatedly cutting the actual amount of correction with the theoretical amount of correction is consistent. 3) the use of the finite element method to simulate the last cut electric discharge energy can reach the discharge pit depth analysis of the relationship between the surface roughness Ra of the discharge pit depth h; the simulation results and the actual test results In comparison, the simulation analysis of the results of the test process for improved guidance. 4) to study the multiple cutting under the conditions of surface quality and to avoid multiple cutting of the surface electrolytic corrosion layer The process proposed in the last cutting process using negative processing, and by using multiple cutting of the last cut in the use of compressed air and spark oil as a cooling medium for the negative processing process of the last cut in order to reduce the discharge of energy, to improve the purpose of multiple cutting surface quality.

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