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polishing surface treatment

Polishing products can not only improve their aesthetics, but also enhance their overall performance such as corrosion resistance and surface hardness.

Polishing is a decorative machining process that uses mechanical, chemical, or electrolytic principles to make the surface roughness of a workpiece smooth and even. It is carried out on the surface of the workpiece using polishing tools, abrasive particles, or other polishing media.

Polishing does not improve the dimensional accuracy and shape accuracy of the workpiece. It only reduces its surface roughness to obtain smooth or mirror like workpieces, and sometimes can also be used to eliminate gloss (extinction).

Polishing tools generally use polishing wheels as the main tool, and polishing agents need to be applied to the wheel rim before polishing the workpiece. Polishing can be divided into mechanical polishing, chemical polishing, electrolytic polishing, ultrasonic polishing, fluid polishing, magnetic abrasive polishing, etc.

Mechanical polishing is the process of removing uneven protrusions from the surface of a workpiece, resulting in a smooth and even curved surface. Generally, oilstone strips, sandpaper, wool wheels, etc. are used, with manual operation being the main method. Special parts such as workpieces with curved surfaces require the use of auxiliary tools such as turntables, and ultra precision grinding can be used to meet the surface quality requirements of the workpiece.

Chemical polishing is the process of placing a workpiece in a chemical medium to dissolve any uneven surface, resulting in a smooth finish. It is somewhat similar to electrolytic polishing, except that chemical polishing does not require electricity and is achieved through chemical reactions.

Electrolytic polishing is a process where the workpiece being polished serves as the anode and insoluble metal serves as the cathode. Both are placed in an electrolytic cell and the metal on the anode surface is dissolved through an electric current reaction, resulting in a smooth surface of the workpiece. Electrolytic polishing can be understood as "reverse electroplating", and its schematic diagram is shown in the following figure:

Ultrasonic polishing is the process of adding abrasive suspension to a workpiece in an ultrasonic field, and using the oscillation effect of ultrasonic waves to polish the surface of the workpiece with the abrasive. It's a bit like a glasses cleaning machine in a glasses store, and I believe friends with myopia will have some experience.

Among various polishing methods, electrolytic polishing is still commonly used.

The polishing effect is as follows:

Most metals can be electropolished, with the most commonly used surface polishing for stainless steel (especially for austenitic nuclear grade stainless steel). Different materials cannot be electrolytic polished simultaneously and cannot be placed in the same electrolytic cell. Plastic products also have polishing methods during the production process - polishing can be done inside the mold or during the pre-treatment before electroplating of the product.

In fact, in addition to the several polishing processes mentioned above, there is another way - CNC machining, but this method has a higher cost and is commonly used for locally polishing the highlighted C-corners of the product to reflect its sense of hierarchy.

Due to the poor working environment of polishing, with the development of CNC and artificial intelligence, mechanical arms can now replace manual polishing operations, greatly improving efficiency and safety. With the development of AI, machines can detect surfaces themselves, perform polishing, and reprocess unpolished surfaces in the future, improving surface yield.

Many sheet metal structural components and machined parts are polished to improve their appearance and make them easier to clean