Next Article in Journal
Hysteresis Compensation and Sliding Mode Control with Perturbation Estimation for Piezoelectric Actuators
Previous Article in Journal
Fabrication and Characterization of Inhomogeneous Curved Artificial Compound Eye
Article Menu
Issue 5 (May) cover image

Export Article

Open AccessArticle
Micromachines 2018, 9(5), 240; https://doi.org/10.3390/mi9050240

How Hydrogen Dielectric Strength Forces the Work Voltage in the Electric Discharge Machining

1
Departamento de Engenharia Mecânica, Faculdade de Engenharia da Universidade do Porto, Rua Roberto Frias, 4200-465 Porto, Portugal
2
Instituto de Engenharia Mecânica (IDMEC), Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais N1, 1049-001 Lisboa, Portugal
*
Author to whom correspondence should be addressed.
Received: 9 April 2018 / Revised: 9 May 2018 / Accepted: 11 May 2018 / Published: 15 May 2018
View Full-Text   |   Download PDF [935 KB, uploaded 18 May 2018]   |  

Abstract

An electro-thermal model based on the Joule heating effect is proposed to simulate a single discharge in an electric discharge machining process. Normally, the dielectric strength of the hydrocarbons oil is approximately 20 MV/m, but it varies with both the thickness of the film and its decomposition. After the breakdown, the hydrocarbon oil has an average dielectric strength value of 2 MV/m. This value is close to the dielectric strength of the hydrogen, which is the main gas that results from the hydrocarbon oil decomposition, at temperatures between 6000 K and 9000 K. Therefore, the electric discharge occurs in a hydrogen atmosphere that imposes both the discharge gap and the work voltage. A 200 V voltage is associated to a 100 μm discharge gap, leading to a 20 V work voltage. Therefore, the 3 V work voltage control corresponds to approximately 15 μm. In other words, the increase of the discharge gap originates other discharge during the discharge pulse. The work voltage control, together with the multiple discharge method, is taken into account. The 100 μm discharge gap corresponds to the higher value of the transitory discharge gap that over evaluates the material removal and the tool wear rates. The results of the numerical simulations are validated with experimental data. View Full-Text
Keywords: electric discharge machining (EDM); dielectric strength; work voltage control; discharge mechanism; multiple discharges; performance electric discharge machining (EDM); dielectric strength; work voltage control; discharge mechanism; multiple discharges; performance
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Almacinha, J.A.; Lopes, A.M.; Rosa, P.; Marafona, J.D. How Hydrogen Dielectric Strength Forces the Work Voltage in the Electric Discharge Machining. Micromachines 2018, 9, 240.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Micromachines EISSN 2072-666X Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top