After spraying, the automobile surface may have some small defects such as coarse grain, sandpaper mark, flow mark, anti white, orange peel, etc. in order to make up for these defects, grinding and polishing treatment is usually carried out after spraying to improve the mirror effect of the paint film and achieve the requirements of bright, smooth and beautiful. Here we will learn about the structure and operation of polishing machine.

The polishing machine is composed of base, throwing plate, polishing fabric, polishing cover and cover. The motor is fixed on the base, and the taper sleeve for fixing the polishing disc is connected with the motor shaft through screws. The polishing fabric is fixed on the polishing disc by ferrule. After the motor is powered on by the switch on the base, the sample can be polished by hand with pressure on the rotating polishing disc. The polishing liquid added in the polishing process can flow into the square plate placed beside the polishing machine through the drainage pipe of the plastic plate fixed on the base. The polishing cover and cover can prevent dust and other impurities from falling on the polished fabric when the machine is not in use, which will affect the use effect.

The key to the operation of the polishing machine is to get the maximum polishing rate so as to remove the damaged layer as soon as possible. At the same time, the polishing damage layer will not affect the final observed structure, that is, it will not cause false structure. The former requires the use of coarser abrasives 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 finest material, so that the polishing damage layer is 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 surface damage caused by rough polishing, which 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 by polishing machine, the grinding surface of the sample and the polishing disc should be absolutely parallel and gently pressed on the polishing disc evenly. Attention should be paid to prevent the sample from flying out and producing new grinding marks due to excessive pressure. At the same time, the sample should rotate and move back and forth along the radius of the turntable, so as to avoid the local abrasion of the polished fabric too fast. In the polishing process, the micro powder suspension should be added continuously to keep the polishing fabric keep a certain humidity. If the humidity is too low, the hard phase will be convex and the non-metallic inclusions in the steel and the graphite phase in the cast iron will lead to tail dragging phenomenon; if the humidity is too low, the heat generated by friction will increase the temperature of the sample, reduce the lubrication effect, and even cause black spots on the grinding surface, and the light alloy will scratch the surface. In order to achieve the purpose of rough polishing, it is required that the rotating speed of the rotary table should be low, and it is better not to exceed 500r / min; the polishing time should be longer than the time needed to remove the scratch, because the deformation layer should also be removed. After rough polishing, the grinding surface is smooth but dull, and there are even and fine grinding marks under the microscope, which need to be eliminated by fine polishing. The speed of the turntable can be increased properly during the fine polishing, and the polishing time is suitable for discarding the damaged layer of the rough polishing. After polishing, the polished surface is as bright as a mirror, and no scratch can be seen in the bright field of microscope, but it can still be seen under the condition of phase contrast illumination.

The quality of polishing machine seriously affects the structure of the sample, which has gradually attracted the attention of experts. In recent years, a lot of research work has been done on the performance of polishing machines at home and abroad. Many new models and new generation polishing equipment have been developed from the original manual operation to various semi-automatic and full-automatic polishing machines. The following describes the performance and characteristics of several commonly used mechanical polishing machines. Polishing machine is specially designed for the surface and pipe treatment of steel, aluminum and copper and other metal products. Dozens of original accessories can meet different needs. It is easy to produce snowflakes, drawlines, wavy patterns, matte surfaces and mirrors with different precision. It can quickly repair deep scratches and slight scratches, quickly grind and polish, weld seams, nozzle marks, traces of oxide film, stains and paints It is suitable for deburring, forming fillet and decorative metal processing. It will not form shadow, transition zone and uneven decorative surface in the processing process. It is an important equipment in metal product production line.

Polishing machine structure is simple, still need to be used correctly, do a good job in daily maintenance, use should pay attention to the following points. When the continuous working time of the polishing machine is too long, the friction heat generation temperature of the polishing roller is high, and the leather surface is easy to be scalded. Before and after work, the surface of polishing roller should be cleaned and waxed to keep the surface smooth and dust-free. In use, the pressure of feeding roller should be controlled properly, so as to avoid too much resistance and burning out of electrical appliances. Do a good job in the lubrication of the rotating parts of the transmission chain, and keep the transmission accurate and reliable.