Effect of jet velocity on metal removal ability of a biomachining solution and its mechanism

Three metal (Fe, Co, and Cu) workpieces were processed with a culture solution of Acidithiobacillus ferrooxidans at various jet velocities, and the material removal rate (MRR) was obtained for each metal. The surface topography, roughness, and elements of the workpieces were also measured. The influence of the jet velocity on the MRR was analyzed. The results indicated that the jet velocity significantly influenced the MRR. The maximum MRR was up to 39.7 times that in the shaking mode. A power function relationship exists between the MRR and jet velocity for each metal. The cations participating in a unit of time, pits on the surface, and dissolved oxygen are essential factors affecting the MRR at various jet velocities. These results will be useful for the development of new methods to improve MRR for effective biomachining.