Explanation of Material Surface Treatment Processes

Surface treatment is a process that involves artificially forming a layer on the surface of a substrate material with mechanical, physical, and chemical properties different from the substrate. The purpose of surface treatment is to meet the requirements for corrosion resistance, wear resistance, decoration, or special functional features of products. Common surface treatment methods include mechanical polishing, chemical treatment, surface heat treatment, and spray coating. Surface treatment involves cleaning, sweeping, deburring, degreasing, and removing oxide scale from the surface of workpieces. Today, let's delve into the process of surface treatment.

Common surface treatment processes include vacuum plating, electroplating, anodizing, electrolytic polishing, pad printing, galvanizing, powder coating, water transfer printing, screen printing, and electrophoresis.

Vacuum Plating

Vacuum plating is a physical deposition phenomenon. In a vacuum state, argon gas is injected, which collides with the target material, causing it to disintegrate into molecules that are adsorbed by the conductive product to form a uniform and smooth metallic-like surface layer.

Applicable Materials:

Many materials can be vacuum plated, including metals, hard and soft plastics, composites, ceramics, and glass. Aluminum is the most commonly used material for electroplating, followed by silver and copper.

Natural materials are not suitable for vacuum plating because their moisture content affects the vacuum environment. Process Cost: The labor cost of vacuum plating is quite high due to the need for spraying, loading, unloading, and re-spraying, but it also depends on the complexity and quantity of the workpieces.

Environmental Impact: Vacuum plating has a minimal environmental impact, similar to that of spray coating.

Electrolytic Polishing

Electrolytic polishing is an electrochemical process where the atoms of a workpiece immersed in an electrolyte are converted into ions and removed from the surface by the passage of current, achieving the effect of removing fine burrs and increasing brightness.

Applicable Materials:

Most metals can be electrolytically polished, with stainless steel being the most commonly used for surface polishing, especially austenitic nuclear-grade stainless steel.

Different materials cannot be electrolytically polished at the same time and should not be placed in the same electrolytic solvent.

Process Cost: The electrolytic polishing process is largely automated, resulting in low labor costs. Environmental Impact: Electrolytic polishing uses less harmful chemicals, requires a small amount of water, and is simple to operate. It can also extend the properties of stainless steel, delaying corrosion.

Pad Printing

Pad printing is becoming an important special printing method that can print text, graphics, and images on irregularly shaped object surfaces.

Applicable Materials: Almost all materials can be used for pad printing, except for materials softer than the silicone pad, such as PTFE.

Process Cost: Low mold cost, low labor cost.

Environmental Impact: Due to the use of soluble inks (which contain harmful chemicals), this process has a significant environmental impact.

Galvanizing

Galvanizing is a surface treatment technology that involves coating a layer of zinc on the surface of steel alloy materials for aesthetic and rust-prevention purposes. The zinc layer serves as an electrochemical protective layer to prevent metal corrosion, primarily using hot-dip galvanizing and electroplating.

Applicable Materials: Galvanizing is suitable for the surface treatment of steel and iron due to its reliance on metallurgical bonding technology.

Process Cost: No mold cost, short cycle/medium labor cost, as the surface quality of the workpiece largely depends on the manual surface treatment before galvanizing.

Environmental Impact: Galvanizing can extend the lifespan of steel parts by 40 to 100 years, effectively preventing rust and corrosion, thus having a positive effect on environmental protection. Additionally, galvanized parts can be returned to the galvanizing tank after their lifespan, and the reuse of liquid zinc does not produce chemical or physical waste.

Electroplating

Electroplating is a process that uses electrolysis to attach a layer of metal film to the surface of parts, preventing metal oxidation, improving wear resistance, conductivity, reflectivity, corrosion resistance, and enhancing aesthetics. Many coins also have an electroplated outer layer.

Applicable Materials:

Most metals can be electroplated, but different metals have different levels of purity and electroplating efficiency. The most common metals include tin, chromium, nickel, silver, gold, and rhodium.

The most commonly electroplated plastic is ABS.

Nickel metal should not be used for products that come into contact with skin due to its irritation and toxicity.

Process Cost: No mold cost, but fixtures are required to secure parts during electroplating/time cost depends on temperature and metal type/labor cost (medium-high), depending on the type of electroplating parts, such as silverware and jewelry, which require highly skilled workers due to their high aesthetic and durability requirements.