A NEW MECHANISM OF GRINDING WHEEL LOADING PHENOMENON EVALUATED BY MACHINING A MAGNESIUM ALLOY

摘要

Grinding-wheel loading can be defined as ground material either adhere to abrasive grains or become embedded in voids on a grinding-wheel surface. This phenomenon deteriorates grinding-wheels, and consequently the surface integrity of ground materials, such as surface roughness of the ground materials due to excessive friction and heat. Newly developed cup-type diamond-grinding-wheels with hexagonal pattern were used to grind a magnesium alloy AZ31B in the present work.rnThe hexagon edges of 1 or 2 mm width contain diamond grains and, the inside of hexagons contains porous green carborundum without diamond grains. The direction of hexagonal edges can be located roughly either parallel or perpendicular to wheel-rotating direction, i. e., wheel-circumferential direction or wheel-radial direction, respectively. Wheel loadings appear in the hexagonal edges along circumferential direction on hexagonal wheel surfaces, but do not appear in those along radial direction, while appear equally at any positions on conventional wheel surface. Previous researches considered that the mechanism of the loading was based on rather microscopic phenomenon, i. e., caused by one grain or neighboring two abrasive grains. In this paper, a new phenomenological mechanism of wheel loading is presented in which the mechanism of wheel loading is totally different to those proposed by the previous researches. Hexagonal structure shows the advantage to reduce wheel loading phenomenon in grinding light metals such as magnesium alloys.