基于内充液回转电极电火花铣削加工的加工工艺研究

发布时间：2019-03-02 07:49

【摘要】：随着电火花加工技术的发展,电火花铣削加工由于其不需要制备对应形状成型电极的优势,已经成为工业生产中,尤其是三维型腔模具加工时常用的加工方式。内充液回转电极电火花铣削加工作为电火花铣削的一个发展方向,在工艺上有了很大的改善,但是仍然存在着工具电极损耗与补偿的问题,本文主要研究的是基于内充液回转电极的电火花铣削加工技术,分别从理论分析、加工策略、工艺改进三方面来进行研究,研究内容主要包括:(1)从加工机理上进行理论分析,内充液回转电极电火花铣削加工技术与传统电火花加工基本相同,大体上可分为四个阶段:极间介质的电离、击穿和放电通道的形成;电极材料的熔化、汽化和极间介质的热分解;电蚀产物的抛出;极间介质的消电离。相对于传统电火花铣削加工,内充液回转电极电火花铣削加工主要有三个工艺改进点:一是放电介质采用水基工作液;二是采用了高压内冲液的方法强化排屑能力;三是加工过程中工具电极自身作回转运动,提高了电极损耗的均匀性。因此,相对于传统电火花铣削加工,该加工技术拥有更高的加工速度和电极损耗均匀性。(2)在工具电极轴向补偿和定长补偿法的基础上,提出了一种能够得到较高加工速度和加工精度的电火花铣削加工策略。基于工具电极轴向自动补偿,通过调节工具电极的横向走刀速度,实现不间断的连续加工。并建立了数学模型,可结合材料蚀除速率、电极损耗比、电极补偿精度、轴向进给深度、放电间隙等参数,计算出理想的横向进给速度,以用于内充液回转电极电火花铣削加工,并通过工艺实验验证了该加工策略的可行性。最后分析了加工轨迹规划对加工速度和加工精度的影响。(3)通过工艺实验,分别从三个方面研究了内充液回转电极电火花铣削加工的加工工艺。首先是电参数,分别研究了峰值电流和脉冲宽度对加工速度、相对电极损耗、被加工表面粗糙度的影响;然后研究了复合电极在内充液回转电极电火花铣削中的应用;最后研究了分散剂工作液在内充液回转电极电火花铣削加工中的影响。通过分析实验结果,针对不同的工艺因素,给出了工艺优化的方向。
[Abstract]:With the development of EDM technology, EDM has become a common machining method in industrial production, especially in 3D cavity die processing, because it does not need to prepare the corresponding shape forming electrode. As a developing direction of EDM, EDM with internal liquid-filled rotating electrode has been greatly improved, but there are still some problems in tool electrode loss and compensation. This paper mainly studies the EDM machining technology based on the internal liquid-filled rotary electrode, which is studied from three aspects: theoretical analysis, machining strategy and process improvement. The main contents are as follows: (1) the machining mechanism is analyzed theoretically. The machining technology of EDM with liquid-filled rotating electrode is basically the same as that of traditional EDM, which can be divided into four stages: ionization of interpolar medium; Breakdown and formation of discharge channels; The melting of electrode materials, vaporization and thermal decomposition of the interpolar medium; the throwing out of the corrosion products; the elimination of the ionization of the interpolar medium. Compared with the traditional EDM machining, there are three main technological improvements in EDM machining with liquid-filled rotary electrode: one is that the discharge medium is water-based working fluid, the other is the method of high-voltage internal flushing liquid to strengthen the chip removal ability, and the other is to use the high-voltage internal flushing method to enhance the chip removal ability. Third, the tool electrode itself rotates in the process of machining, which improves the uniformity of electrode loss. Therefore, compared with the traditional EDM machining, the machining technology has higher machining speed and uniform electrode loss. (2) on the basis of tool electrode axial compensation and fixed length compensation method, this machining technology has higher machining speed and electrode loss uniformity. (2) on the basis of tool electrode axial compensation and fixed length compensation method, An EDM strategy which can obtain high machining speed and machining precision is presented in this paper. Based on automatic axial compensation of tool electrode, continuous machining is realized by adjusting the lateral walking speed of tool electrode. The mathematical model is established. The ideal transverse feed velocity can be calculated by combining the parameters such as material erosion rate, electrode loss ratio, electrode compensation precision, axial feed depth, discharge gap, etc. It is used in EDM machining of internal liquid-filled rotary electrode, and the feasibility of the machining strategy is verified by technological experiments. Finally, the influence of machining trajectory planning on machining speed and machining precision is analyzed. (3) the machining technology of EDM machining with internal liquid filled rotary electrode is studied from three aspects through technological experiments. Firstly, the effects of peak current and pulse width on machining speed, relative electrode loss and surface roughness are studied, and then the application of composite electrode in EDM with liquid-filled rotary electrode is studied. Finally, the effect of dispersant working fluid on EDM machining with liquid-filled rotating electrode was studied. Through the analysis of the experimental results, the direction of process optimization is given according to different process factors.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG661;TG54

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