What are the types of polishing

1. Mechanical Polishing

Mechanical polishing is a method of achieving a smooth surface by removing the convex parts through cutting and plastic deformation of the material. It typically involves the use of oil stones, wool wheels, sandpaper, and similar tools, primarily operated manually. For special parts such as rotary surfaces, auxiliary tools like rotary tables can be employed. For surfaces requiring high quality, ultra-fine polishing is utilized. This process uses specially designed abrasives, which are tightly pressed onto the workpiece surface and rotated at high speeds while submerged in an abrasive slurry. This technique can achieve a surface roughness of Ra 0.008, the highest among all polishing methods. It is commonly used for optical lens molds.

2. Chemical Polishing

Chemical polishing involves dissolving the micro-convex parts of a material's surface preferentially over the concave parts in a chemical medium, resulting in a smooth surface. The primary advantages of this method are the absence of complex equipment, the ability to polish workpieces with intricate shapes, the simultaneous polishing of multiple workpieces, and high efficiency. The core issue in chemical polishing is the preparation of the polishing solution. The surface roughness achieved through chemical polishing typically ranges from tens of micrometers.

3. Electrolytic polishing

The fundamental principle of electrochemical polishing is the same as that of chemical polishing, which involves selectively dissolving the microscopic protrusions on the material's surface to achieve a smooth finish. Compared to chemical polishing, it can eliminate the influence of cathode reactions, resulting in better performance. The electrochemical polishing process consists of two steps.

① Macroscopic leveling allows the dissolution products to diffuse into the electrolyte, reducing the surface roughness of the material, with Ra > lum.

② Microscopic smoothing of anode polarization, improved surface roughness, Ra < 1 μm

4. Ultrasonic Polishing

Place the workpiece into the abrasive suspension and immerse both together in an ultrasonic field. The oscillatory action of the ultrasonic waves causes the abrasives to grind and polish the workpiece surface. Ultrasonic machining involves minimal macroscopic forces, preventing workpiece deformation, but tooling fabrication and installation are relatively challenging. Ultrasonic machining can be combined with chemical or electrochemical methods. By applying ultrasonic vibration to agitate the solution, it enhances the removal of dissolved products from the workpiece surface, ensuring uniform corrosion or electrolyte distribution near the surface. Additionally, the cavitation effect of ultrasonic waves in liquids

It can also inhibit the corrosion process and contribute to surface brightening.

Five, Fluid Polishing

Fluid polishing achieves the purpose of polishing by relying on the high-speed flow of liquid and the abrasive particles it carries to scour the workpiece surface. Common methods include abrasive jet machining, liquid jet machining, and hydrodynamic polishing. Hydrodynamic polishing is driven by hydraulic pressure, causing the liquid medium carrying abrasive particles to flow rapidly back and forth over the workpiece surface. The medium primarily consists of specially formulated compounds (polymer-like substances) with good flow properties under low pressure, mixed with abrasive particles. The abrasive material can be silicon carbide powder.