超声振动辅助电弧加工技术及机理

发布时间：2018-03-28 21:33

本文选题：超声振动　切入点：电弧加工　出处：《北方工业大学》2017年硕士论文

【摘要】：硬脆材料具有硬度大、脆性高等特点,使用传统方法对硬脆材料进行加工难度很大。电火花加工是利用两极间产生火花放电来蚀除硬脆材料,在加工过程中不产生机械力,具有较高的加工效率。电弧加工类似于电火花加工,电弧加工利用电极间产生放电电弧群组来蚀除材料,电弧加工产生的电流密度远大于电火花加工产生的电流密度,因此电弧加工相比电火花加工具有更高的加工效率,但加工精度有待提高。本文探讨超声振动辅助对电弧加工精度的影响。通过电火花加工机理研究电弧加工机理,对电弧放电过程中放电通道的形成、材料的蚀除、蚀除材料的排出和极间介质消电离四个方面进行了研究。同时根据超声振动的特性,研究了超声振动对电弧加工过程中放电通道、极间距、蚀除物排出和加工表面质量的影响,发现超声振动有助于改善电弧放电情况,促进蚀除物的脱离和排出。根据超声振动辅助电弧加工的技术要求,设计主体为X、Y、Z三坐标轴和旋转主轴的四轴实验平台,大理石板和立柱一起构成实验平台的支架。对核心部件旋转主轴进行了设计,该旋转主轴具备电极旋转和超声振动的功能。并重点对圆锥过渡阶梯型复合变幅杆进行了设计,通过Pro-E进行三维建模,运用Ansys进行模态分析,对变幅杆进行优化。超声振动辅助电弧加工数控系统采用以研华-610L工控机为上位机和IMAC-400运动控制卡为下位机的主从开放式数控系统。根据超声振动辅助电弧加工原理,制定了数控系统的控制策略,对伺服进给系统进行了分析。运用软件Pewin32Pro2调节PID参数使伺服电机能够及时响应并稳定工作,对电机进行了开环测试。利用超声振动辅助电弧加工实验平台进行不同厚度弹簧合金钢在有超声振动和没有超声振动时电弧放电加工小孔实验,将小孔显微图形通过Matlab进行小孔边缘检测和圆度计算。通过进行对比研究,结果表明超声振动辅助下加工的小孔质量更好,边缘更加圆滑。
[Abstract]:Hard and brittle materials have the characteristics of high hardness and high brittleness. It is very difficult to use traditional methods to process hard brittle materials. EDM uses spark discharge between the two poles to erode hard and brittle materials, and no mechanical force is produced in the process of machining. Arc machining is similar to EDM. Arc machining uses discharge arc groups between electrodes to erode materials. The current density produced by arc machining is much greater than that produced by EDM. Therefore, the arc machining has higher machining efficiency than EDM, but the machining precision needs to be improved. This paper discusses the influence of ultrasonic vibration on the arc machining accuracy, and studies the arc machining mechanism through the EDM mechanism. The formation of discharge channels, the erosion of materials, the discharge of etched materials and the deionization of interpolar dielectric during arc discharge are studied. At the same time, according to the characteristics of ultrasonic vibration, The effects of ultrasonic vibration on discharge channel, electrode spacing, removal of etch and surface quality during arc machining are studied. It is found that ultrasonic vibration is helpful to improve arc discharge. According to the technical requirements of ultrasonic vibration assisted arc machining, a four-axis experimental platform is designed, which is composed of three axes and a rotating spindle. Dali stone slabs and columns are used to form the experimental platform together. The rotating spindle of the core component is designed, which has the functions of electrode rotation and ultrasonic vibration. Three-dimensional modeling is carried out through Pro-E, modal analysis is carried out by using Ansys. The ultrasonic vibration aided arc machining numerical control system adopts the master and slave open NC system, which takes Yanhua 610L industrial control computer as upper computer and IMAC-400 motion control card as lower computer. According to the principle of ultrasonic vibration assisted arc machining, The control strategy of the NC system is formulated, and the servo feed system is analyzed. The PID parameters are adjusted by the software Pewin32Pro2 to make the servo motor respond in time and work stably. The open loop test of the motor was carried out. The experiments of machining holes in different thickness spring alloy steel with and without ultrasonic vibration by arc discharge were carried out by using ultrasonic vibration assisted arc machining experiment platform. The micrographs of the holes are detected by Matlab and the roundness is calculated. The results show that the holes processed by ultrasonic vibration have better quality and more smooth edges.
【学位授予单位】：北方工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG66

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