Improvement of Wire Electrical Discharge Machining Characteristics in Machining Boron-doped Polycrystalline Diamond Using a Novel Iso-pulse Generator

  • Mu-Tian YanEmail author
  • Yu-Chih Cheng
  • Shenq-Yih Luo
Regular Paper


This study aims to present a novel iso-pulse generator for improving machining characteristics of boron-doped polycrystalline composite diamond (BD-PCD) by wire electrical discharge machining (wire-EDM). The transistor-controlled pulse generator composed of a high-power source circuit, a low-power source circuit, a snubber circuit and a complex programmable logic device based pulse control circuit was devised to provide a high open voltage during the ignition period and a low peak current with a fixed discharge duration for sparking as well as identify gap states as normal sparks and abnormal sparks based on the duration of ignition delay time. Pulse on-time and pulse interval of each spark are regulated in real-time to achieve the stability of machining operation while preventing wire electrode from breaking according to the identified gap state. Compared to a conventional iso-frequency pulse generator, the developed iso-pulse generator can provide smaller variation of peak current and discharge duration and thus, the latter can enable the wire-EDM process to produce smaller surface damages and better surface quality than the former. Experimental results not only verify the iso-pulse generator can achieve a fine surface finish as low as Ra 0.247 μm on machined surface of BD-PCD through one rough and one finish machining operation, they also demonstrate that the developed system can enable a table-top wire-EDM machine to successfully sharpen the cutting edge of BD-PCD end milling tools.


Wire-EDM Boron-doped polycrystalline composite diamond Pulse generator Surface finish 

List of Symbols

M1, M2, M3

Metal-oxide semiconductor field-effect transistor (MOSFET)

P1, P2, P3

Pulse control signal of MOSFET


Threshold pulse signal


Ignition delay time


Pulse on-time


Pulse duration of high-power source


Pulse off-time


A threshold period of 1 μs


Spark generating signal



This research was supported by the Ministry of Science and Technology, Taiwan under Grant No. :MOST 104-2221-E-167 -035 -MY2.


  1. 1.
    Jia, Y., Kim, B. S., Hu, D. J., & Ni, J. (2010). Parametric study on near-dry wire electrodischarge machining of polycrystalline diamond-coated tungsten carbide material. Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 224(2), 185–193.CrossRefGoogle Scholar
  2. 2.
    Hsu, F. C., Tai, T. Y., Vo, V. N., Chen, S. Y., & Chen, Y. H. (2013). The machining characteristics of polycrystalline diamond (PCD) by Micro-WEDM. Procedia CIRP, 6, 261–266.CrossRefGoogle Scholar
  3. 3.
    Galindo-Fernandez, M., Diver, C., & Leahy, W. (2016). The prediction of surface finish and cutting speed for wire electro-discharge machining of polycrystalline diamond. Procedia CIRP, 42, 297–304.CrossRefGoogle Scholar
  4. 4.
  5. 5.
    Suzuki, K., Shiraishi, Y., Nakajima, N., Iwai, M., Ninomiya, S., Tanaka, Y., et al. (2009). Development of new PCD made up of boron doped diamond particles and its machinability by EDM. Advanced Materials Research, 76–78, 684–689.CrossRefGoogle Scholar
  6. 6.
    Chen, S. T., & Chang, C. H. (2012). Study on thinning of a boron-doped polycrystalline diamond wheel-tool by micro rotary W-EDM approach. Applied Mechanics and Materials, 217-219, 2167–2170.CrossRefGoogle Scholar
  7. 7.
    Chen, W., Ninomiya, S., Nochi, S., Iwai, M., & Suzuki, K. (2014). Wire-EDM properties of EC-PCD made up of boron doped diamond particles. Advanced Materials Research, 1017, 770–775.CrossRefGoogle Scholar
  8. 8.
    Cheng, X., Wang, Z., Nakamoto, K., & Yamazaki, K. (2011). A study on the micro tooling for micro/nano milling. The International Journal of Advanced Manufacturing Technology, 53(5–8), 523–533.CrossRefGoogle Scholar
  9. 9.
    Cheng, X., Yang, X. H., Huang, Y. M., Zheng, G. M., & Li, L. (2014). Helical surface creation by wire electrical discharge machining for micro tools. Robotics and Computer-Integrated Manufacturing, 30(3), 287–294.CrossRefGoogle Scholar
  10. 10.
    Yan, M. T., Fang, G. R., & Liu, Y. T. (2013). An experimental study on micro wire-EDM of polycrystalline diamond using a novel pulse generator. The International Journal of Advanced Manufacturing Technology, 66(9–12), 1633–1640.CrossRefGoogle Scholar
  11. 11.
    Yan, M. T., & Lin, T. C. (2016). Development of a pulse generator for rough cutting of oil-based micro wire-EDM. Procedia CIRP, 42, 709–714.CrossRefGoogle Scholar
  12. 12.
    Yan, M. T., & Chiang, T. L. (2009). Design and experimental study of a power supply for micro wire-EDM. The International Journal of Advanced Manufacturing Technology, 40(11–12), 1111–1117.CrossRefGoogle Scholar
  13. 13.
    Schroder, R. E., Nemanich, R. J., & Glass, J. T. (1990). Analysis of the composite structures in diamond thin films by Raman spectroscopy. Phys Rev B, 41, 3738–3745.CrossRefGoogle Scholar

Copyright information

© Korean Society for Precision Engineering 2019

Authors and Affiliations

  1. 1.Graduate Institute of Precision ManufacturingNational Chin-Yi University of TechnologyTaichungRepublic of China
  2. 2.Department of Mechatronic EngineeringHuafan UniversityNew Taipei CityRepublic of China

Personalised recommendations