Processo Híbrido Mecânico-Eletroquímico de Usinagem de Ultraprecisão da liga Ti-6Al-4V

Abstract

The manufacture of features and mechanical components on a micrometer scale, associated with the rise of the industrial area of miniaturization, has demanded the improvement and development of techniques capable of fulfilling the imposed needs in terms of surface finish and dimensional and macrogeometric tolerances. Micromachining associated with the hybridism among different energy sources emerges as promising ideas and capable of attend the demanding criteria of geometric precision of the results obtained. In this context, the main objective of this work is to produce workpieces that present nanometric surface roughness (Ra < 100 nm), through the association between microgrinding abrasive mechanical tests and a previous electrochemical passivation surface preparation, in samples of Ti-6Al-4V. To this end, a mini-machine was adapted for the development of microgrinding, in which the devices designed and manufactured for the electrochemical tests were also used to protect its structure. Initially, microgrinding tests were performed machining microslots on grounded with abrasive papers surfaces (non-passivated) and the roughness values found were used as reference for comparing the influence of electrochemical preparation prior to mechanical machining. The results obtained showed an expressive numerical reduction on the values of the roughness parameters Ra, Rq, Rz, Rp, Rv and Rt, in the range of 62 %, 64 %, 72 %, 78 %, 63 %, and 75 %, respectively, proving to have a positive influence in terms of surface finish regarding the previous passivation by electrochemical. Topographic images of the micromachined channels considering a constant and variable depth of cut did not detect the significant presence of burrs on the lateral edges. The lowest value obtained for Ra was 33 nm, allowing the classification of the technique as ultraprecision.