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Why Surface Treatment Matters for CNC Parts
Surface treatment and surface finishing are critical for CNC machined parts to improve corrosion resistance, wear resistance, aesthetics, and functionality. From anodized aluminum to plastic surface finishing, these processes ensure parts meet the demands of industries like aerospace, automotive, and electronics.
Why Surface Treatment?
Surface treatment enhances part longevity, protects against environmental factors, and improves visual appeal. Processes like metal surface treatment and anodizing are essential for high-performance applications.
CNC machining works with metals (e.g., aluminum, steel, stainless steel, titanium, brass) and plastics (e.g., ABS, PC, PP, PMMA, POM). Each material requires specific surface finishing techniques.
From aerospace surface treatment to plastic surface finish for consumer products, our solutions cater to diverse industries, ensuring precision and quality.
Our Surface Treatment Range
We offer a variety of surface finishing options to enhance the texture, hardness, smoothness, chemical resistance, and corrosion resistance of 5 axis CNC machining parts. These finishes effectively cover tool marks left by machining, ensuring a refined and flawless product appearance. Here are some of the most common finishing options:
| Material Type | Surface Finishing | Applications |
| Metals | Sanding， Polishing, Bead Blasting, Anodizing, Electroplating, Powder Coating, Painting, PVD Coating, Chromating, Passivation, Black Oxiding, Nitriding, Brushing, Laser Etching, Chemical Etching | Aerospace, Automotive |
| Plastics | Sanding, Polishing, Bead Blasting, Vapor Polishing, Painting, Electroplating, Anodizing, Powder Coating, UV Coating, Silk Screening, Pad Printing, Laser Etching, Chemical Etching, Heat Staking, Ultrasonic Welding | Medical, Electronics |
Type of Surface Treatment
1. Basic treatment of part surfaces：Deburring & Smoothing
Natural Color
CNC machined metal, natural color, no need for any surface treatment.
Sand Blasting
Cleans the CNC Machining Parts surface and increases the roughness to improve the adhesion of the coating.
Electropolishing
Smooths the surface through electrochemical dissolution, suitable for parts with complex shapes.
Tumbling
Use a barrel or vibrating process with abrasives to smooth and polish the surface of the parts.
2. Protection & Wear Resistance
Anodizing
Applicable to aluminum-titanium-magnesium alloys, forming an oxide film to enhance corrosion resistance and hardness, such as hard oxidation (Type III) for aviation parts.
Plating
Zinc plating (rust prevention), nickel plating (wear resistance), chrome plating (decoration + wear resistance), commonly used for screw automotive accessories.
Passivation
A chemical process that forms a protective oxide layer on stainless steel to enhance corrosion resistance.
Polishing
Mechanically or chemically smooths surfaces for a mirror-like finish, enhancing aesthetics for stainless steel and aluminum surface treatment.
3. Aesthetics & Decoration
Brushing
Brushing forms linear textures and is used for electronic product housings.
Powder Coating
Curing after electrostatic spraying provides a variety of colors and wear-resistant surfaces.
Black Oxide
Black oxide film on the surface of steel parts, which is both rust-proof and beautiful.
Blue Oxide
A chemical process applying a blue-black oxide coating on steel to boost corrosion resistance and add a decorative finish.
4. Functional Enhancement
Chemical Nickel Plating
Uniform coating, improved hardness and corrosion resistance.
Microarc Oxidation
Aluminum/magnesium alloy surface ceramic film, high temperature resistance and insulation.
Nitriding Treatment
Nitriding can make the surface of parts have higher hardness and wear resistance, stable up to 500-600℃
Heat Treatment
Alters metal structure through heating and cooling to enhance hardness, strength, or toughness.
5. Combined Processes & More
Anodizing + Dyeing
Used for surface treatment of metal materials such as aluminum alloy to enhance their decorative properties and corrosion resistance.
Bead-Blasting Plating
Increase the adhesion of electroplating, richer appearance, and extend service life.
Laser Marking
Use laser to engrave information such as marks, text, patterns, etc. on the surface of the material onto the object. Applicable to metal, plastic, ceramic, glass, etc.
Silk screen printing
A process that prints patterns or text on CNC parts using a mesh screen, enhancing aesthetics and functionality for marking or decoration.
Natural Color
For the original colors of the various plastic materials, as well as the processed surfaces and textures, see Plastic Materials.
Grinding
Deburring, grinding, bonding marks, etc., to improve the surface finish.
Polishing
Further reduce surface roughness, increase glossiness, make the prototype smooth or shiny, or remove gloss
Sandblasting
Use small particles sprayed at high speed to grind the plastic surface, remove dirt and increase roughness, and improve paint adhesion.
Texture
It creates a textured plastic surface, boosting friction by over 30% to improve grip and anti-slip performance.
UV Coating Spraying
Using special coatings such as UV coatings, which can cure in a short time to form a high hardness protective layer. The use of UV coatings can reduce production time by more than 30%.
Powder Coating
Through electrostatic powder spraying, the powder coating melts and solidifies on the plastic surface, forming a uniform and solvent-free coating. The utilization rate of the powder coating can reach over 95%.
Electroplating
Used for surfaces with high reflectivity and abrasion resistance, with higher requirements for the environment.
Chemical plating
Metal layers are chemically deposited on plastic surfaces, adding metallic luster and conductivity. In electronics, chemical plating enhances plastic components’ electromagnetic compatibility and shielding.
Vacuum Coating (PVD)
In a vacuum, PVD forms a metal film on plastic, enhancing aesthetics with effects like aluminum or silver plating, improving durability and corrosion resistance for automotive and consumer goods.
Anodizing
Special coatings and electrochemical reactions form an oxidized film on plastic, boosting corrosion and wear resistance, with surface hardness reaching 6H after anodic oxidation.
Water transfer printing
Water transfer printing is suitable for complex plastic products, achieving richly colored patterns.
Laser engraving
Using lasers to engrave fine patterns or text on the surface of plastics, laser engraving technology features high processing precision and no contact damage.
IMD/OMD
The in-mold decoration technology directly transfers patterns onto the plastic surface during the injection molding process, suitable for large-scale production. The scrap rate of products using IMD technology can be reduced to below 1%.
Silk screen printing
Also known as screen printing, it is the most widely used printing process and can be suitable for products in a variety of industries as long as there is a flat area on the product.
Our Surface Treatment Applications
Discover how our advanced solutions can revolutionize your approach, providing efficiency and unprecedented growth.
Benefit from our team’s extensive knowledge and receive tailored advice to meet your unique challenges.
Our products are designed for easy integration, ensuring a smooth transition and immediate productivity.
Our Portfolio of Surface Finishing
Our cnc parts finishing services are exceptional as our teams are experts in plastic, composite, and metal surface finishing. Furthermore, we have state-of-the-art machines and infrastructure to bring your idea to life.
CNC Parts Surface Finishing FAQs
Bead blasting and spray painting are among the most affordable options. Anodizing is also cost-effective for aluminum parts with good performance benefits.
Most surface finishing processes take between 1 to 3 working days, depending on the method and volume. Complex finishes or large quantities may require more time.
Some surface finishes, like plating or powder coating, may slightly affect part dimensions. If tight tolerances are required, please inform us before production so we can adjust accordingly.
Anodizing is one of the most popular surface finishes for aluminum CNC parts. It enhances corrosion resistance, provides a clean appearance, and is available in various colors. For improved hardness, hard anodizing is recommended.
A: Yes. For example, anodizing can be followed by laser marking or polishing.
Yes, many surface treatments like anodizing, spray painting, and powder coating can be customized with specific colors to match your branding or product design.
Surface finishing refers to post-processing methods applied to CNC machined parts to improve their appearance, surface quality, durability, corrosion resistance, and functionality. Common finishes include anodizing, polishing, plating, painting, and bead blasting.
Bead blasting creates a matte, uniform texture that hides machining marks, while polishing produces a shiny, reflective surface. The choice depends on your desired aesthetics and function.
While not always necessary, plastic parts can benefit from surface treatments like painting, UV coating, or laser marking for enhanced appearance and branding.
Hard anodizing, powder coating, and electroless nickel plating offer excellent durability, wear resistance, and corrosion protection for metal CNC parts.