MACHINABILITY OF PURE METALS BY ELECTRICAL DISCHARGE MACHINING

Pedro Miguel Horta Sousa, Ivo Manuel Ferreira de Bragança, Abílio Manuel Pinho de Jesus, José Duarte Ribeiro Marafona, Pedro Alexandre Rodrigues Carvalho Rosa

Resumo


Electrical discharge machining (EDM) involves the generation of micro-plasmas subjected to high temperature and pressure to promote the material removal. Hence, to understand the material removal mechanism it is of great importance the knowledge of the interaction plasma-solid. Knowing how physical and chemical properties of materials affect heat transfer at the electrode surface, how this eventually affects electrical properties of the plasma channel over the discharge time are key issues to achieve a better understanding of this machining technology. This research attempts to provide some answers to these issues by means of single plasma discharge tests under laboratory-controlled conditions carried out on pure and low-alloyed materials in favour of comprehensiveness and forthcoming numerical modelling. These results demonstrate that material eroded volume is correlated with process operating parameters and that crater morphology has presented a more regular shape in pure metals than in engineering materials. The machinability index of the materials under study has been determined by calculations of the eroded volume and electrical power measures. Further to the low predictability of the models presented in literature, it was also proposed a basic conceptual model referring to the morphology of the eroded craters.


Referências


ABDULKAREEM, S.; KHAN, A.; KONNEH, M. Reducing electrode wear ratio using cryogenic cooling during electrical discharge machining. Int. Journal Advanced Manufacturing Technologies, v.45, 2009.

BRAGANÇA, I.M.F.; ROSA, P.A.R.; DIAS, F.M.; MARTINS, P.A.F.; Alves, L.L. Experimental study of micro electrical discharge machining discharges. Journal of Applied Physics, v.113, n.23, 2013a.

BRAGANÇA, I.M.F.; RIBEIRO, G.R.; ROSA, P.A.R.; MARTINS, P.A.F. Prototype machine for micro-EDM. In: Nontraditional Machining Processes, London, Springer, p.153-76, 2013b.

DESCOEUDRES, A. Characterization of electrical discharge machining plasma. 2006. PhD Thesis, École Polytechnique Fédérale de Lausanne, France.

DIBITONTO, D.D.; EUBANK, P.T.; PATEL, M.R.; BARRUFET, M.A. Theoretical models of the electrical discharge machining process, a simple cathode erosion model. Journal of Applied Physics, n.66, 4095-4103, 1989.

EUBANK, P.; PATEL, M.; BARRUFET, M.; BOZKURT, B. Theoretical models of the electrical discharge machining process: the variable mass, cylindrical plasma model. Journal of Applied Physics, n.73, 1993.

LIU, Y.; ZHANG, Y.; JI, R.; CAI, B.; WANG, F.; TIAN, X.; DONG, X. Experimental characterization of sinking electrical discharge machining using water in oil emulsion as dielectric. Materials and Manufacturing Processes, v.28, n.4, p.355-63, 2013.

KANEMARU, M.; Sorimachi, S.; Ibuka, S.; Ishii, S. Single bubble generated by a pulsed discharge in liquids as a plasma microreactor. Publishing Ltd Plasma Sources Science and Technology, v.20, n.3, 2011.

KHAN, A. Role of Heat Transfer on Process Characteristics During Electrical Discharge Machining. 2011. PhD Thesis, International Islamic University, Malaysia,

KUNIEDA, M.; LAUWERS, B.; RAJURKAR, K.P.; SCHUMACHER, B.M. Advancing EDM through fundamental insight into the process. Annals of the CIRP, v.54, p.599-622, 2005.

LU, C.T. Influence of current impulse on machining characteristics in EDM. Journal of Mechanical Science and Technology, 2007.

POPA, M. Surface Quality of the EDM Processed Materials. XIX IMEKO World Congress; Fundamental and Applied Metrology, Lisbon, Portugal, September 6−11, 2009.

REYNAERTS, D.; HEEREN P.; VAN BRUSSEL H. Microstructuring of silicon by electro-discharge machining (EDM) - part I: theory. Machine design Automation, Belgium, Sensors and Actuators, v.A60, p.212-218, 1997.

SALONITIS, K.; STOURNARAS, A.; STAVROPOULOS, P.; CHRYSSOLOURIS, G. Thermal modeling of the matérial removal rate and surface roughness for die-sinking EDM. The International Journal of Advanced Manufacturing Technology, v.40, n.3, p.316-323, 2009.

SHUMACHER, B.M. After 60 years of EDM the discharge process remains still disputed. Journal of Materials Processing Technology, v.149, p.376–381, 2004.

YEO, S.H.; KURNIA, W.; TAN, P.C. Critical assessment and numerical comparison of electro-thermal models in EDM. Journal of Materials Processing Technology, v.203, n.1, p.241-251, 2008.

ZHANG, Y.; LIU, Y.; JI, R.; DONG, X. Research of the rheology of water-in-oil emulsion used in die-sinking EDM. Chinese Journal of Mechanical Engineering, Jixie Gongcheng Xuebao, v.47, p.188–93, 2011.


Texto completo: PDF (English)

Apontamentos

  • Não há apontamentos.


Licença Creative Commons
Este trabalho está licenciado sob uma Licença Creative Commons Attribution 3.0 .

ISSN: 2446-9580