气体放电加工基础工艺试验研究

采用单因素法进行了基本的工艺参数(电参数、伺服参考电压等)对气体介质放电加工性能影响的试验研究。试验结果表明:气体介质的放电加工适于采用正极性加工。在试验加工的范围内,工件的蚀除速度和表面粗糙度值随脉冲宽度和峰值电流的增加而增加,随脉冲间隔的增加而减小。极间并联合适的电容能够使加工速度和加工表面粗糙度有所改善,并对此现象进行了分析。对于某一确定的加工参数,存在一个较佳的伺服参考电压值,使加工性能较为稳定。工具电极具有较高的旋转速度能够使气体放电加工性能得到提高。使用氧气介质能够实现快速电火花加工,并根据不同气体的物理性能对不同气体介质的加工性能进行了分析。工件表面显微硬度测试结果表明:空气中放电加工的工件的表面硬度比基体硬度高,比煤油中加工的工件表面硬度低。

EXPERIMENTAL STUDY ON ELECTRICAL DISCHARGE MACHINING IN GAS

Adopting single factor method, Experimental studies on electrical discharge machining in gas (dry EDM) are carried out to realize the effect of basic operating parameters (such as electrical parameters, gap voltage, etc.) on machining performance. Experimental results indicate that it is suitable for work-piece use as anode and tool electrode as cathode. It is observed that the material remove rate (MRR) and surface roughness (SR) increase with the increase of pulse duration and peak current, and decrease with the increase of pulse interval in the range of the experimental data . It is found that the MRR is increase and SR improve when a suitable capacitance is parallel connected with tool electrode and workpiece; and the reasons producing the phenomena are analyzed. For a given parameters, there is an optimal gap voltage at which better machining performance can be obtained. Better machining characteristic of dry EDM can be achieved with higher tool electrode rotate speed. Analyzed the machining performance of different gas media on base of physical characteristics of different gases media and found that the MRR machining in oxygen medium is the highest. It is found that surface micro-rigidity ED machining in air higher than that of base material and lower than that of ED machining in kerosene.