Polishing machine polishing is an important process in the process of processing. With the extensive application of hardware products, the appearance quality requirements of hardware products are getting higher and higher, so the quality of surface polishing should be improved accordingly, especially the mirror surface. Products with high-gloss, high-gloss surfaces require higher surface finishes and therefore require higher polishing. Polishing not only increases the aesthetics of the workpiece, but also improves the corrosion resistance and wear resistance of the surface of the material.
Currently commonly used polishing has the following:
Mechanical polishing is a polishing method that removes the polished convex portion by plastic deformation on the surface of the material to obtain a smooth surface. Generally, oil stone strips, wool wheels, sandpaper, etc. are used, which are mainly manual operations, and special parts such as the surface of the rotating body can be used. Using an auxiliary tool such as a turntable, the method of super-fine polishing can be used with high surface quality requirements. Ultra-fine grinding and polishing is a special-purpose grinding tool. In the polishing liquid containing abrasive, it is pressed against the machined surface to perform high-speed rotary motion. With this technology, a surface roughness of Ra0.008 μm can be achieved, which is the highest among various polishing methods. This method is often used in optical lens molds.
The general process of mechanical polishing is as follows:
The surface after rough polishing, milling, grinding, etc. can be polished by a rotary surface polishing machine with a rotational speed of 35 000-40 000 rpm.
The general order of use is #180 ~ #240 ~ #320 ~ #400 ~ #600 ~ #800~ #1000.
Tips in mechanical polishing:
Polishing with sandpaper should pay attention to the following points:
When changing to different types of sandpaper, the polishing direction should be changed from 45° to 90°, so that the streak shadow left by the polishing of the former type of sandpaper can be distinguished. Before changing the different types of sandpaper, the polished surface must be carefully wiped with 100% pure cotton dipped in a cleaning solution such as alcohol, because a small amount of gravel left on the surface will destroy the entire polishing work. This cleaning process is equally important when polishing from sandpaper to diamond polishing. All pellets and kerosene must be completely cleaned before polishing continues.
In order to avoid scratching and burning the surface of the workpiece, special care must be taken when polishing with #1200 and #15000 sandpaper. It is therefore necessary to load a light load and polish the surface using a two-step polishing method. When polishing with each type of sandpaper, it should be polished twice in two different directions, with each rotation between 45° and 90°.
For high quality polishing, polishing methods and tools that are prone to heat should be avoided. For example: polishing wheel polishing, the heat generated by the polishing wheel can easily cause "orange peel".
The effect of different hardness on the polishing process.
The increase in hardness increases the difficulty of grinding, but the roughness after polishing decreases. Due to the increased hardness, the polishing time required to achieve lower roughness is correspondingly increased. At the same time, the hardness is increased and the possibility of over-polishing is correspondingly reduced.
- The influence of the surface condition of the workpiece on the polishing process
During the crushing process of steel machining, the surface layer may be damaged by heat, internal stress or other factors, and improper cutting parameters may affect the polishing effect. The hardness of the hardened layer is higher than the hardness of the substrate and must be removed. Therefore, it is better to add a rough grinding process to completely remove the damaged surface layer to form an average rough metal surface, which provides a good basis for polishing.