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Effect of low-frequency vibration on workpiece in EDM processes
Gunawan Setia Prihandana,Muslim Mahardika,M. Hamdi,Kimiyuki Mitsui 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.5
High-frequency vibration aided EDM has become one of the ways to increase material removal rate in EDM process, due to the flushing effect caused by vibration. However, utilizing high-frequency vibration, especially in ultrasonic range consumes a lot of setup cost. This work presents an attempt to use a low-frequency vibration on workpiece of stainless steel (SS 304) during EDM process. The workpiece was vibrated with variations of low-frequency and low-amplitude. The results show that the application of low-frequency vibration in EDM process can be used to increase the material removal rate, and decrease the surface roughness and tool wear rate.
Study of Workpiece Vibration in Powder-Suspended Dielectric Fluid in Micro-EDM Processes
Gunawan Setia Prihandana,Muslim Mahardika,Mohd Hamdi,Yoke San Wong,Norihisa Miki,Kimiyuki Mitsui 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.
Abstract. In micro-EDM (electrical discharge machining), improper removal of debris causes short-circuiting between a tool electrode and a workpiece and in turn, prevents continuous machining process. Therefore, a remarkably longer period of time is required to fabricate a through hole than that would be required when no short-circuiting took place. In order to solve this problem, the dielectric fluid is immersed with graphite nano powders to reduce machining time and improve surface quality due to the less frequent of arcing between the tool electrode and the workpiece. However, excess powders become debris and subsequently deteriorate the efficiency of machining. To fully exploit the effects of the suspended powders, we introduced vibration of the workpiece in order to remove the debris in the small gap between the workpiece and electrode efficiently. The experimental results showed that combination of these techniques improved machining stability, assured continuous machining processes, and significant reduction of the machining time. Reduction of the machining time and the surface roughness of the workpiece after machining were investigated with respect to the powder concentrations when the workpiece was vibrated at 1000 Hz.
Precision machining by discharge pulse counting methods in micro EDM processes
Muslim Mahardika,Gunawan Setia Prihandana,Kimiyuki Mitsui 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.11
Due to the occurrences of debris, the ability of micro-EDM to produce precise dimension is degraded, hence positioning display indicator of micro-EDM machine is not accurately measure the real dimension. Therefore, imprecise workpiece dimension is happen. In order to overcome this problem, in this paper, the use of discharge pulse counting methods to correct this error is introduced. The dimension error from micro-EDM processes by using discharge pulse counting method is much smaller than when using the positioning display indicator of micro-EDM machine. Hence, by using discharge pulse counting method, high precision machining can be achieved.