Abrasive sheet
1. Define and abrasive sheet processing principle
By coating or press-fitted in the lap of the abrasive particles through the lap and the workpiece relative motion at a certain pressure on the processing surface of the finishing process (such as cutting). Abrasive sheet can be used for processing a variety of metallic and non-metallic materials, with a flat surface shape processing, internal and outer cylindrical and conical surfaces, convex, concave spherical, thread, and other tooth surface profile. Precision up to IT5 ~ 01, surface roughness up Ra0.63 ~ 0.01 microns.
Abrasive sheet is a very complex process, so it has not been able to explain the formation of a unified theory of all phenomena related to grinding, over a long period of observation and research, at present, there are three: mechanical grinding theory: that the cerium oxide particles cut with CG, cutting diamond particles similar.
Chemistry Theory: A prominent peak of the glass layer by hydrolysis to remove the punch. Surface heat flow theory: frictional heat caused by hot melt flow, resulting in a smooth surface.
These three theories have some validity in varying degrees, based on the combined effect of the three, it is also proposed a fourth view that the abrasive sheet is complicated process machinery, chemistry and physics of three roles.
Debris forming principle: the abrasive grains arranged in spacing and height are randomly distributed abrasive is a polyhedron, each of its corners can be regarded as a cutting edge, the top angle of approximately 90 ° ~ 120 ° , a tip radius of several micrometers to tens micrometers arc. Finely trimmed its abrasive grit surface will form a minor cutting edge, known as micro-edge. Grains have large negative rake angle at the time of grinding, the average is about -60 °. Abrasive cutting process can be divided into three stages.
① swipe phases: abrasive began to squeeze into the workpiece, swipe over, the elastic deformation of the workpiece surface without the chip;
② Plough phases: abrasive intrude depth increased, plastic deformation of the workpiece, plowing into the groove, and the front sides of the abrasive grains piled high ridge;
③ cutting stage: plunging depth continues to increase, the temperature reaches or exceeds the critical temperature of the workpiece material, workpiece material part obviously slip along the shear plane formed by debris.