Views: 69 Author: Site Editor Publish Time: 2022-06-17 Origin: Site
The key to the polishing machine operation is to try to get the maximum polishing rate so as to remove the damage layer from the polishing as soon as possible. At the same time, the polished damage layer will not affect the final observed tissue, that is, the false tissue will not be caused.
The former requires the use of coarse abrasive, in order to ensure a larger polishing rate to remove the polished damage layer, but the polishing damage layer is also deeper, the latter requires the use of the most fine materials, so that the polishing damage layer is lighter, but the polishing rate is low. The best way to solve this problem is to divide the polishing into two stages. The purpose of coarse casting is to remove the polished damage layer, this phase should have the largest polishing rate, the surface damage caused by rough throw is secondary consideration, but it should also be as small as possible, followed by fine-parabolic (or final-cast), which aims to remove the surface damage caused by rough throw and minimize the polishing damage. Polishing machine polishing, the sample grinding and polishing discs should be absolutely parallel and evenly light on the parabolic disc, pay attention to prevent the specimen from flying out and because of too much pressure to produce new grinding marks. At the same time should also make the specimen rotation and the direction of the wheel radius to move back and forth to avoid the polished fabric local wear too quickly in the polishing process to continuously add micro-powder suspension, so that the polished fabric to maintain a certain humidity. Humidity too assembly to weaken the polishing effect of the grinding scar, so that the hard phase of the specimen is floating convex and non-metallic inclusions in steel and graphite in cast iron produces a "drag tail" phenomenon; humidity is too small, due to friction heat will make the sample temperature, lubrication reduced, grinding loss of luster, or even black spots, light alloy will be thrown on the surface. In order to achieve the purpose of coarse throw, the rotary speed is lower, it is best not to exceed the 600r/min; the polishing time should be longer than the scratch, as the deformation layer should be removed.
After coarse throw, smooth, but bleak, under the microscope to observe a uniform and meticulous grinding marks, to be eliminated by fine polishing. The speed of the turntable can be raised properly when the polishing is thrown, and the damage layer of the coarse throw is suitable. After fine polishing, the grinding is as bright as a mirror, and no scratches can be seen under the microscope, but it is still visible under the condition of contrast illumination. The quality of polishing machine polishing seriously affect the structure of the sample, has gradually aroused the attention of experts. At home and abroad in the performance of the polishing machine has done a lot of research work, the study of a number of new models, the next generation of polishing equipment, is from the original manual operation developed into a variety of semi-automatic and automatic polishing machine.