The key to the operation of the polishing machine is to try to get the maximum polishing rate in order to remove the damage layer produced during polishing as soon as possible. At the same time, it is necessary to ensure that the polishing damage layer will not affect the final observed tissue, that is, it will not cause false tissue. The former requires the use of coarser abrasives to ensure a greater polishing rate to remove the polished damage layer, but the polishing damage layer is also deeper; the latter requires the use of the finest materials to make the polishing damage layer shallower, but the polishing damage layer is deeper. The rate is low.
The best way to solve this contradiction is to divide the polishing into two stages. The purpose of rough polishing is to remove the polishing damage layer. This stage should have the largest polishing rate. The surface damage caused by rough polishing is a secondary consideration, but it should be as small as possible; followed by fine polishing (or final polishing), Its purpose is to remove the surface damage caused by coarse polishing and minimize the polishing damage. When the polishing machine is polishing, the grinding surface of the sample and the polishing disc should be absolutely parallel and evenly pressed lightly on the polishing disc, and attention should be paid to prevent the sample from flying out and new grinding marks due to too much pressure. At the same time, the sample should be rotated and moved back and forth along the radius of the turntable to avoid local wear of the polishing fabric too quickly. During the polishing process, the micropowder suspension should be continuously added to keep the polishing fabric at a certain humidity. If the humidity is too high, the grinding effect of polishing will be weakened, and the hard phase in the sample will appear embossed, and the non-metallic inclusions in steel and the graphite phase in cast iron will produce a "tailing" phenomenon; if the humidity is too low, the heat generated by friction will make the sample When the temperature rises, the lubricating effect will decrease, the grinding surface will lose its luster, and even black spots will appear, and the light alloy will scratch the surface. In order to achieve the purpose of coarse throwing, the rotary speed of the turntable is required to be low, preferably not more than 600r/min; the polishing time should be longer than the time required to remove the scratches, because the deformed layer must be removed. After rough polishing, the polished surface is smooth, but dull, and there are uniform and fine wear marks under the microscope, which need to be eliminated by fine polishing.
The speed of the turntable can be increased appropriately during fine polishing, and the polishing time is appropriate to throw away the damaged layer of rough polishing. After fine polishing, the ground surface is as bright as a mirror, and no scratches can be seen under the bright field conditions of the microscope, but the wear marks can still be seen under the phase contrast illumination conditions. The polishing quality of the polishing machine seriously affects the tissue structure of the sample, which has gradually attracted the attention of relevant experts. A lot of research work has been done on the performance of polishing machines at home and abroad, and many new models and a new generation of polishing equipment have been developed. The original manual operation is developing into a variety of semi-automatic and fully automatic polishing machines.
The performance and characteristics of several commonly used mechanical polishing machines are introduced below. Polishing is specially designed for the effect treatment of the surface and pipes of metal products such as steel, aluminum, copper, etc. Dozens of original accessories meet different needs, and it is easy to produce various snow patterns, brushed patterns, wavy patterns, and matte with different precision. surface, mirror surface, etc., quickly repair deep scratches and slight scratches, quickly polish and polish; In the process of processing, it will not form shadows, transition zones and uneven decorative surfaces. It is an important equipment for metal product production lines. The polishing machine is suitable for the following industries: wood, furniture industries such as flat wood, furniture metal handles and other workpiece sanding and wire drawing; hardware (metal) materials and products, aluminum profiles and their products, stainless steel products and utensils, copper profiles and products, plumbing and bathroom equipment , locks, lighting products, nameplates, hardware craft accessories, knives and scissors, door hinges, automobile and bicycle parts, tableware, buckle products, buttons, belt buckles, mobile phone casings, watch industry and other workpiece sand Light drawing; electronic parts, electronic equipment such as electronic parts, flat sanding and drawing, etc.
