In the process of diversification and high-grade development of industrial products, how to improve the surface quality of parts that directly affects product quality is an important task. Therefore, it is necessary to perform a polishing process on the surface of the part, so what are the commonly used polishing methods? What tools are commonly used in polishing?

We will explain it to you in this article!

Commonly used polishing methods

Mechanical polishing

Mechanical polishing is a polishing method that removes the protrusions on the surface of the workpiece by cutting or plastically deforming the surface of the material to obtain a smooth surface. Generally, oil stone strips, wool wheels, sandpaper, etc. are used, and manual operations are mainly used. High surface quality requirements can be used. The method of ultra-fine grinding and polishing. Ultra-fine polishing uses a special abrasive tool, which is pressed against the surface of the workpiece to be processed in a polishing liquid containing abrasives for high-speed rotation. Using this technology, the surface roughness of Ra0.008 μm can be achieved, which is the best surface roughness among various polishing methods. Optical lens molds often use this method.

Chemical polishing

Chemical polishing is a chemical medium in which the protruding part of the surface is preferentially dissolved compared to the concave part, so as to obtain a smooth surface. This method can polish workpieces with complex shapes, and can polish many workpieces at the same time, with high efficiency. The surface roughness obtained by chemical polishing is generally Ra10 μm.

Electropolishing

The basic principle of electrolytic polishing is the same as that of chemical polishing, that is, to make the surface smooth by selectively dissolving the tiny protrusions on the surface of the material. Compared with chemical polishing, it can eliminate the influence of cathodic reaction, and the effect is better.

Ultrasonic polishing

Ultrasonic polishing is a processing method that uses the ultrasonic vibration of the tool section to polish brittle and hard materials through abrasive suspension. The workpiece is put into the abrasive suspension and placed together in the ultrasonic field, and the abrasive is ground and polished on the surface of the workpiece by means of ultrasonic oscillation.

Fluid polishing

Fluid polishing relies on the flowing liquid and the abrasive grains it carries to scour the surface of the workpiece to achieve the purpose of polishing. Hydrodynamic grinding is driven by hydraulic pressure. The medium is mainly made of special compounds (polymer-like substances) that flow well under relatively low pressure and mixed with abrasives. The abrasives can be silicon carbide powder.

Magnetic grinding and polishing

Magnetic grinding and polishing is to use magnetic abrasives to form abrasive brushes under the action of a magnetic field to grind the workpiece. This method has high processing efficiency, good quality, and easy control of processing conditions.

EDM ultrasonic composite polishing

In order to increase the polishing speed of workpieces with a surface roughness Ra of 1.6 μm or more, ultrasonic waves and special high-frequency narrow-pulse high-peak current pulse power sources are used for composite polishing. its surface roughness.

Common tools and specifications for polishing

Commonly used tools for polishing parts include: sandpaper, oil stone, felt wheel, abrasive paste, alloy file, diamond grinding needle, bamboo chip, fiber oil stone, circular rotary grinder, etc.

The following are the specification categories of some tools for polishing:

Sandpaper: 150#, 180#, 320#, 400#, 600#, 800#, 1 000#, 1 200#, 1 500#;

Whetstone: 120#, 220#, 400#, 600#;

Tape wheel: cylindrical, conical, square tip;

Grinding paste: 1# (white) 3# (yellow) 6# (orange) 9# (green) 15# (blue) 25# (brown) 35# (red) 60# (purple);

Files: square, round, flat, triangular and other shapes;

Diamond grinding needle: generally 3/32 shank or 1/8 shank, with circular waveform, cylindrical shape, long straight column shape, long circular cone shape;

Bamboo slices: Various shapes are suitable for the operator and the shape of the mold. The function is to press the sandpaper and grind on the workpiece to achieve the required surface roughness;

Fiber oil stone: 200# (black) 400# (blue) 600# (white) 800# (red).

Hope the above content can help you!