Essential Guide to Surface Treatment for the Manufacturing Industry

I. What is Polishing?
Polishing is a processing method that uses machinery to reduce the roughness of a workpiece's surface, resulting in a shiny and smooth surface. It is not only a "beautification technique" for improving the appearance of products, but also an important functional process that enhances corrosion resistance, prolongs service life, and reduces friction.

II. Why is polishing necessary for products?
Enhance appearance: Achieve a smooth and shiny surface, thereby increasing the visual appeal of the product.

Improve performance: Reduce the surface friction coefficient, enhancing the wear resistance and assembly accuracy of the workpiece.

Strengthen durability: Remove minor cracks and defects on the surface, increasing the corrosion resistance and fatigue resistance.

Cleanliness and hygiene: A smooth and pore-free surface is easier to clean and disinfect, meeting the requirements of the medical and food industries.

Increase value: A meticulous polishing process can significantly enhance the brand value and market price of the product.

III. Main Categories of Polishing Methods
Based on the degree of automation and principles, polishing can be classified into the following major categories:
1. Manual Polishing
Description: Operators use tools such as angle grinders, sand wheels, sandpapers, and oil stones to perform grinding by relying on their experience.
Advantages: High flexibility, suitable for extremely complex or large-sized workpieces.
Disadvantages: Extremely low efficiency, poor consistency, high skill requirements for workers, and high cost.
Applicability: Custom production, artworks, mold repair, etc.

This is the mainstream method for deburring, chamfering and batch pre-polishing in industrial production at present.
Principle: By automatically controlling the robotic arm or polishing head, it performs precise and repetitive polishing operations along a preset path on the workpiece. Various tool heads such as sand belts, polishing wheels, and grinding discs can be integrated.
Core Advantages:
Extremely high consistency: Completely replicates the polishing path to ensure that the effect of each workpiece is exactly the same.
Significantly improved efficiency: 24-hour continuous operation, with efficiency being tens of times higher than manual work, significantly reducing single-piece costs.
Reduced reliance on human resources and technical barriers: Programming operation, ordinary employees can manage it, solving the problem of recruitment difficulties.
Improved working environment: Usually integrates dust removal systems to ensure the health of employees.
Applicable: Batch polishing of metal products, such as the body of mobile phone cases, laptop computer shells, hardware kitchenware, automotive parts, medical devices, etc.

These methods usually require the operator to hold the workpiece and operate it on the equipment, or be executed by automated mechanical equipment. They are the key steps to achieve a high-gloss surface.

Sanding belt polishing:
Principle: Utilize an electric motor to drive the circular abrasive belt to move at high speed. The workpiece (or a mechanical hand) comes into contact with the abrasive belt for grinding. Different grit abrasive belts can be replaced to gradually polish.
Advantages: Strong cutting force, high efficiency, suitable for quickly removing deep marks and shaping, and easy for automation integration.
Disadvantages: High technical requirements for the operator, not suitable for very complex geometries.
Applicability: Large workpieces (such as stainless steel countertops, door handles), rough grinding and medium polishing of flat surfaces, woodwork polishing.

Polishing wheels polishing:
Principle: Use a rotating cloth wheel, braided wheel or nylon wheel, combined with polishing wax, to perform micro-grinding and produce a lustrous finish on the surface of the workpiece.
Advantages: Can achieve the highest level of mirror finish (Mirror Finish), with a much higher gloss than other methods.
Disadvantages: Completely dependent on the operator's skills, the automation difficulty is slightly higher, and the consumables (polishing wheels, polishing wax) are consumed in large quantities.
Applicable: Final precision polishing and mirror processing, such as automotive electroplated parts, high-end bathrooms, jewelry, tableware surface finishing.