Flat surfaces machining by the magneto-abrasive method with permanent magnet end-type heads. The influence of the design of the working surfaces of the heads on the effectiveness of the magneto-abrasive machining

Abstract

Investigation of the magneto-abrasive machining process of flat surfaces of parts made of ferromagnetic material steel 45 by the end heads based on high-power permanent magnets, which form the magneto-abrasive tool of the "brush" type, was carried out. For ensuring the high efficiency of the magneto-abrasive machining process, an analysis of the machining by heads on the working surfaces of which located protrusions of various shapes, sizes and configurations was carried out. Twelve types of working surfaces were investigated. The control of magneto-abrasive machining process efficiency was curried for the changing of the parameter Ra, the value of the relative roughness and the rate of its change, the size of the surface's relative reference profile length from the section level of the formed microprofile and the parameter of geometric heredity obtained during the machining. It has been determined that the most rational design of the working surface of the end head with the magneto-abrasive tool of the "brush" type was the surface with 9-12 radial triangular protrusions located on it. Using of such heads provides a highly efficient form of the roughness of machined surfaces with Ra < 0.03 µm with an initial Ra of 0.8 µm obtained after face milling. At the same time, microwaves had been formed after milling was almost eliminated. The kinetics formation of the relative reference profile length from the section level was analyzed by the nature of its size change. It has been shown that at the initial stage, the predominant removal of micro peaks had occurred, and then micro valleys were actively machined with further smoothing of the microprofile.