Lubricating film applied to one face of metal sheet or strip - by continuous electrostatic precipitation of lubricant in enclosed chamber

摘要

A thin film of a lubricating substance is applied to a metal sheet or band before the latter passes through a further machining process. The lubricant consists of a dielectric medium which is solid at normal ambient temp. and is deposited on the metal in the form of fine solid spheres with a dia. of ca. 1 micron such that the density of the deposits is 0.0322 g/cm2 and 10% of the surface is covered. Specifically the lubricant is first melted and then atomised to a fine mist of the small spheres. The mist then passes into a non-conducting plasma chamber in which the particles attain the same charge as the gas ions in the chamber. The metal sheet passes thorugh the chamber and carries an opposite charge with the result that the lubricant particles accelerate toward the plate and adhere to the surface. Because of their like charges, the particles are repelled from each other which ensures a fine distribution of the deposited layer.