5475.1:
Surface finishing of ultra-high quality in electroerosion machining with simultaneous deposition of tribological coatings
Abstract
Die-Sinking Electroerosion Machining (EDM) is presently a key industrial technology that uses electric discharges to melt, dig and shape hard materials with a resolution of about 1 mm. The process leaves a rapidly resolidified layer at the workpiece surface, whose properties cannot be totally controlled yet: structural defects as micro-cracks can be observed at its surface. Post-processing is therefore necessary for some applications, which represents supplementary costs.
The fundamental aim of the present project is to master the resolidified layer, first by controlling its topology and microstructure at the nanoscale through the use of nano-powder suspension dielectrics, which will refine and enhance the homogeneity of the discharge pulse energies. In addition, the composition of the resolidified layer will be changed by alloying, during EDM, the elements of the powder suspended materials with those of the workpiece, in such a way to create an anti-crack surface layer. Furthermore, this alloying technique will allow to give to workpiece surfaces enhanced tribological properties, namely a superior hardness and wear resistance.
In order to achieve those objectives it is projected (1) to produce, characterize and test a large collection of nano-powder suspensions, (2) to adapt the EDM generator excitation to this new media conditions by using results of modelling , simulation and experimental work on the thermal effect of plasma discharges on workpieces, and (3) to study in detail the structure, the composition and the tribological properties of resolidified layers, this at the nanoscale. The project will lead to the creation of a new technology of ultra-high quality finishing EDMand simultaneous coating deposition that will open to Agie-Charmilles the future markets of nano-technology.