The method on which the chemically accelerated isotropic superfinishing process is based, is a non-abrasive mechanical / chemical process that results in a series of beneficial properties that go beyond the reduction of friction, as:
- the process is carried out in acqueous solution, so that the pieces don’t undergo alterations due to overheating;
- the process is based on a surface conversion reaction that does not generate hydrogen, therefore it is metallurgically safe;
- there are no damages to pieces geometry.
Unlike surface finishing carried out with other techniques, this kind of surfaces are unequaliable in their exceptional ability to reduce friction, wear, noise and contact stress. The chemical activator which produces the conversion reaction is, by chemical definition, neutre (PH ~ 5,5) and the process is normalli conducted at room temperature. Therefore there is no possibility of hydrogen embrittlement or grinding burn, as it commonly happens in mechanical grinding operations.
The acrivator produces a stable conversion coater on the surface of the metallic pieces to be treated, which is more thender than the basic metal. The superfinishing process removes the conversion coating from the ‘peaks’ of the surfaces of the pieces, eliminating a micro layer of metal, but it leaves the ‘valleys’ unchanged. The process is carried out until the surfaces of the pieces are smooth, free from roughness and with the desired surface finish degree.
The final polishing does not remove metal, but completely removes the conversion coating remaining from the pieces surface, producing a speculare appearance and applying at the same time a light layer of anti-rust protection to the surface.
The super-finishing allows to obtain surfaces with roughness even up to 0,01 μm and a non oriented surface texture; the isotropic surface, without preferential directions of the geometrico conformation, allows the components to be more resistant. The traditional techniques of grinding, honing and lapping do not eliminate the roughness, but turn them into rows of shorter asperities. The parts treated in this way during their functioning are subjected to an intense deformation, wear and contact stress.
The difference between a rectified surface and a ISOTROPIC super-finished surface is evident: in addition to a reduction of roughness, it’s possible to note a removal of all the traces left by the cutting edges of the cuttin wheel.
The most evident imbrovemet on the components is the reduction of friction caused by a ultra smooth surface; moreover, the friction reduction also causes a significative reduction of noise, operating temperatures, pitting phenomenon, wear and eddy clutches. Basically the ISOTROPIC super-finishing treatment allows to obtain several advantages: geater yield and legthening of the pieces life, reduction of consumptions, costs, fritcions, operating temeratures and increase of mechanical performances.