1. Improvement of Dry EDM Characteristics Using Piezoelectric Actuator
姓名：陳依剛
學號：m97r0211
日期：２００９／６／9

2. content
Abstract
Introduction
Experimental results
Conclusions

3. Abstract
This describes improvement of the machining characteristics of dry electrical discharge machining (dryEDM) by controlling the discharge gap distance using a piezoelectric actuator.

4. INTRODUCTION
Dry electrical discharge machining (dry EDM) is a new process which uses gas instead of liquid as the dielectric fluid.
Dry EDM is characterized by small tool electrode wear, negligible damage generated on the machined surface

5. Figure 1 shows the high frequency response servo-feed system which was newly developed for dry milling EDM by one of the authors . To raise the frequency response of the servo-feed system, a piezoelectric actuator is installed on the working table to adjust the working gap distance.

6. HIGH FREQUENCY RESPONSE SERVO-FEED SYSTEM

7. DRY EDM SIMULATION

8. Discharge delay time

9. Effect of piezoelectric servo in experiment

10. Experimental results
The horizontal axis indicates the gain of the driver for the piezoelectric actuator. Zero gain means that machining was performed using the Z-axis servo only, without using the piezoelectric servo system. In this case, the probability of short circuiting reached 95%. With increasing gain of the driver for the piezoelectric actuator, the probability of short circuiting decreases, resulting in considerable increase of the material removal rate.

11. Simulation of time variation of gap distance without piezoelectric servo system

12. Time variation of gap distance with piezoelectric servo.

13. CONCLUSIONS
A piezoelectric servo system was developed to improve the frequency response of the gap control in dry EDM.
In that the use of the piezoelectric servo system stabilizes the gap control resulting in the considerable increase of the material removal rate of dry EDM

14. Thanks for Your Attention