The key to the operation of polishing machine is to try to get the maximum polishing rate, so as to remove the damaged layer during polishing as soon as possible. At the same time, the polishing damage layer should not affect the final observed tissue, that is, it will not cause false tissue. The former requires the use of coarse abrasive to ensure a large polishing rate to remove the polished damage layer, but the polishing damage layer is also deep; The latter requires the use of the finest material to make the polishing damage layer shallow, but the polishing rate is low.
The best way to solve this contradiction is to divide polishing into two stages. The purpose of rough polishing is to remove the polishing damage layer. This stage should have the maximum polishing rate. The surface damage formed by rough polishing is a secondary consideration, but it should also be as small as possible; The second is fine polishing (or final polishing), which aims to remove the surface damage caused by rough polishing and minimize the polishing damage. When polishing with the polishing machine, the grinding surface of the sample and the polishing disc shall be absolutely parallel and evenly pressed on the polishing disc, and attention shall be paid to prevent the sample from flying out and generating new grinding marks due to too much pressure. At the same time, make the sample rotate and move back and forth along the radius of the rotary table to avoid local wear of the polished fabric too fast. In the polishing process, continuously add micro powder suspension to keep the polished fabric at a certain humidity. Too much humidity will weaken the effect of polishing wear marks, make the hard phase in the sample appear convex, and the "tail dragging" phenomenon of non-metallic inclusions in steel and graphite phase in cast iron; When the humidity is too small, the friction heat will raise the temperature of the sample, reduce the lubrication, lose the luster of the grinding surface, and even appear black spots, and the light alloy will damage the surface. In order to achieve the purpose of rough polishing, the rotating speed of the rotary table is required to be low, preferably not more than 600r / min; The polishing time should be longer than the time required to remove the scratch, because the deformation layer should also be removed. After rough polishing, the grinding surface is smooth but dull. Uniform and fine grinding marks are observed under the microscope and need to be eliminated by fine polishing.
During fine polishing, the speed of rotary table can be appropriately increased, and the polishing time is appropriate to throw away the damaged layer of rough polishing. After fine polishing, the grinding surface is as bright as a mirror, and no scratches can be seen under the bright field of view of the microscope, but the grinding marks can still be seen under the condition of phase contrast lighting. The polishing quality of the polishing machine seriously affects the microstructure 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 new generation of polishing equipment have been developed. They are developing from the original manual operation to a variety of semi-automatic and full-automatic polishing machines.
The following describes the performance and characteristics of several commonly used mechanical polishing machines. The polishing machine is specially used for the effect treatment of the surface and pipes of metal products such as steel, aluminum and copper. Dozens of original accessories meet different needs. It is easy to produce snowflake lines, wiredrawing lines, wavy lines, matte surfaces, mirrors, etc. with different accuracy, quickly repair deep scratches and slight scratches, and quickly polish and polish; Weld, nozzle mark, oxide film, stain and paint are suitable for deburring, fillet forming and decorative metal processing. They will not form shadow, transition zone and uneven decorative surface in the processing process. They are important equipment of metal product production line. The polishing machine is applicable to the following industries: sanding and wire drawing of workpieces in wood and furniture industries, such as flat wood, furniture metal handle and so on; 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, signs and nameplates, hardware process accessories, knives and scissors, movable leaves of doors, auto and bicycle parts, tableware, button products, buttons, belt buttons, mobile phone shell, clock and watch industry and other workpiece sanding and wire drawing; Electronic parts, electronic equipment, such as electronic parts, flat sanding wire drawing, etc.