1. Forming Fine V-Grooves on a Tungsten Carbide Work piece with a PCD Electrode by EDM 報告者 : 謝聖尉 日期 :2/26

2. Introduction 為了能實現精密的放電加工，並且減少電極的消耗率。而因 EC-CVD( 化學氣 相沉積金剛石 ) 價格昂貴，找到類似的材料 PCD （聚晶金剛石），並去做一些 參數來比較這兩種材料的差別，以及利用一組比較的參數，使用銅鎢電極做 為放電並觀察表面組織及電極消耗等特性。

3. PCD Material Used

4. EDM Properties of PCD Electrodes with Flat Surface

6. EDM Properties of PCD Electrode with V Shape (1) Shape of the PCD electrode(2) Fine groove machining condition

7. EDM Properties of PCD Electrode with V Shape (2) Fine groove machining condition

8. EDM Properties of PCD Electrode with V Shape (2) Fine groove machining condition

9. EDM characteristics using PCD electrode (1)Effect of no-load voltage

10. EDM characteristics using PCD electrode (1)Effect of no-load voltage

11. EDM characteristics using PCD electrode (2) Effect of set ED current

12. EDM characteristics using PCD electrode (2) Effect of set ED current

13. EDM characteristics using PCD electrode (3) Effect of ED duration

14. EDM characteristics using PCD electrode (3) Effect of ED duration

15. Conclusion (1) PCD electrodes with flat surface show an almost zero wear at the long pulse duration and a significantly low wear of 0.6~1.5% at the short pulse duration compared to 10% wear of the Cu- W electrode at suggested condition for EDM on tungsten carbide (G5). (2) The electrode wear is extremely less with PCD electrode compared to a Cu-W electrode and a zero wear machining is achieved by optimizing the ED conditions (ui=60V, ip=2A, te>15μs). (3) Thermal conductivity of PCD is different according to the diamond grain size of the PCD. In this study, it was expected that the electrode with higher thermal conductivity would show less wear. In fact, the result is just as expected, i.e. CTH025 exhibits less wear than CTB010. (4) As the diamond is an insulator, it was expected that the grain size of the diamond would affect ED performance. In order to investigate, how this would affect the electrode wear, various tests were carried out by varying the parameters under the ED condition. However, the result revealed that wear on CTH025 is less than CTB010 although CTH025 is thought to have more contributing factor to cause unstable ED performance.

16. Thank you for attention