1. Name: Chin-Yao Lai M9510242 Adviser: C-H Chuang
Multi-spherical probe machining by EDM Combining WEDG technology with one-pulse electro-discharge
Name: Chin-Yao Lai M
Adviser: C-H Chuang

2. Abstract
This paper describes a hybrid technique combining wire electro-discharge grinding (WEDG) technology with one-pulse electrodischarge (OPED), to fabricate multi-micro-spherical probes. The results show that a burnished micro-spherical probe with diameter of about 40m could be formed instantaneously, which is not available with conventional machining methods。

3. Machining Procedure
The fabrication procedure of a 30 um diameter electrode by WEDG The electrode material is a 300um diameter rod of tungsten, which is available in commercial market
Procedure of OPED system

4. Experimental results and discussion
In comparison to the EDM,OPED system can obtain a spherical probe with excellent smooth surface
Surface roughness of the probe with OPED system
Surface roughness of the probe with Micro-EDM

5. Duration of the OPED system
The experimental results of the relations of the duration and the diameter of the spherical probe
Relations of diameter and duration
Repeatedly machining of OPED system

6. Different cross-section of the microelectrode
WEDG technology is available to fabricate some kinds of cross-section shape of the microelectrodes. Electro-discharge occurred to one of the probes but not to all of the probes simultaneously
The procedures of multi-micro-spherical probes fabrication
multi-micro-spherical probes
probe with tungsten carbide

7. Summary
Compared to the micro-EDM crater, the roughness of the surface of the micro-spherical probe is very smooth. It is expected that a high accuracy of measurement can be achieved by attaching the micro-spherical probe on a CMM。
The experimental results show that multi-microspherical probes can be fabricated, which conventional method is not available. It is also possible to achieve mass production of the spherical probe with combining wire-EDM in the future。
The smallest obtainable electrode diameter was approximately 10um in this study. Using an electrode of this diameter, a 15um diameter spherical probe was fabricated successfully。