The key to the operation of the polishing machine equipment is to try to get the maximum polishing rate so that the damage layer can be removed as soon as possible. It is also necessary that the polished damage layer does not affect the final observed tissue. The former requires the use of thicker abrasive materials to ensure a larger polishing rate to remove the polishing damage layer, but the polishing damage layer is also deeper; the latter requires the use of the finest material to make the polishing damage layer shallower, but the polishing rate is low . The best way to resolve this contradiction is to divide polishing into two stages. The purpose of rough polishing is to remove the grinding damage layer. This stage should have the maximum polishing rate. Surface damage from roughing throws is a secondary consideration, but also as small as possible; followed by fine throws (or final throws).
The purpose is to remove surface damage caused by rough polishing and minimize polishing damage. When polishing the polishing machine equipment, the grinding surface of the sample and the throwing disc should be absolutely parallel and lightly pressed on the throwing disc evenly. Pay attention to prevent the sample from flying out due to excessive pressure and causing new wear marks. At the same time, the sample should rotate and move back and forth along the radius of the turntable, so as to avoid local wear and tear during the polishing process. Add powder suspension continuously, so that the polishing fabric can maintain a certain humidity. The qualitative phase appears convex, and the non-metallic inclusions in steel and the graphite phase in cast iron produce “dragging”.
If the humidity is too low, the sample will heat up due to frictional heat, the lubricity will be reduced, the grinding surface will lose its luster, and even black spots will appear, and the light alloy will polish the surface. At low speed, it is better to be less than 600 r /min; The polishing time should be longer than the time required to remove the scratches, because the deformation layer needs to be removed. The grinding surface is smooth, but dull and dull. There are uniform and fine scratches observed under the microscope, which need to be eliminated by fine polishing. The rotation speed of the grinding wheel can be appropriately increased, the polishing time can be appropriately increased, and the coarse damage layer can be thrown away. The finely polished surface after polishing is as bright as a mirror, which cannot be seen under the bright field of view under the microscope, but is still under the condition of phase contrast illumination. Grinding marks can be seen. The polishing quality of the polishing machine equipment seriously affects the structure of the sample, which has gradually attracted the attention of relevant experts. In recent years, a lot of research work has been done on the performance polishing machine equipment at home and abroad, and many new machines have been developed. Type, a new generation of polishing equipment, is developing from the original manual operation to a variety of semi-automatic and fully automatic polishing machine equipment.
Post time: Oct-22-2022