Electro-Discharge Machined Surfaces

  • J. R. Crookall
  • B. C. Khor
Chapter

Summary

Existing published work on the nature of electro-discharge machined surfaces is reviewed and discussed, including deformation and damage, and metallurgical structure and physico-chemical changes.

Using both optical microscopy and scanning-electron microscopy, the results of an investigation of surface effects and characteristics of both pulse-generator and relaxation-circuit EDM machines on HW5 tool steel, EN1 steel, and copper workpiece materials are presented. The very complex nature of these surfaces is demonstrated. They possess characteristics peculiar to EDM on account, not only of the severity and rapidity of local heating and cooling which occurs, but also due to the discrete, random attack of the discharges. In the light of the evidence presented, conventional roughness measurements by stylus instruments provide a very limited indication of the effective surface characteristics.

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Copyright information

© Macmillan Publishers Limited 1975

Authors and Affiliations

  • J. R. Crookall
    • 1
  • B. C. Khor
    • 1
  1. 1.Imperial College of Science and TechnologyUK

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