Anodizing Aluminum CNC Parts: Advantages and Applications of Versatile Surface Treatments

In CNC aluminum parts, surface treatment plays a crucial role. Whether it’s to enhance the durability of the parts, protect their surfaces, or improve aesthetics, aluminum parts usually undergo specific treatments. Over time, untreated aluminum surfaces may darken or yellow due to exposure. Among the various surface treatments available, anodizing is the most common and widely used for aluminum CNC parts. This process creates a dense oxide layer through anodic oxidation, offering increased corrosion resistance and aesthetic appeal. The anodized layer typically ranges from a few microns to several tens of microns, providing effective protection and enhanced visual quality.  

1. Regular Anodizing  

Regular anodizing is the most commonly used surface treatment for aluminum CNC parts. It involves an electrochemical reaction in an electrolyte solution to form a protective aluminum oxide layer on the surface. This oxide layer typically ranges from 5 to 25 microns in thickness, offering excellent corrosion resistance and oxidation protection, while improving the part's appearance. Regular anodizing is widely applied in industries such as aerospace, electronics, home appliances, and industrial equipment, making it an ideal choice for products requiring cost-effective and basic protection.  

2. Hard Anodizing  

Hard anodizing is an enhanced version of regular anodizing. It forms a thicker and more robust oxide layer, typically between 25 and 150 microns, providing superior wear resistance, corrosion resistance, and insulation properties. This process is ideal for mechanical parts, aerospace components, and customized aluminum parts used in high-stress or high-wear environments.  

Below is an image of a silver CNC-milled part treated with hard anodizing. Compared to regular anodized silver, the color in hard anodized silver leans toward a slight yellow hue. This difference is due to the thickness of the oxide layer in hard anodizing, which affects the shade and variation of the color.  

3. Colored Anodizing  

Colored anodizing is a process that creates anodized layers in multiple colors by adjusting the process parameters and electrolyte composition. This treatment not only provides basic protection but also adds a decorative touch, making parts visually striking. We have produced various aluminum products with colored anodizing, including electronic device enclosures, toy parts, and customized precision racing components. The vibrant colors not only enhance the aesthetic appeal but also help these products stand out, adding a unique personality to each piece.  

4. Anodizing + UV Resistance  

Anodizing with UV resistance is a specialized surface treatment. After the standard anodizing process, additional dyeing techniques are applied to enhance UV resistance. This method significantly improves the aluminum parts’ durability in outdoor environments by preventing color fading and performance degradation caused by prolonged sunlight exposure. While this process is less commonly requested, its importance is growing as more products are designed for outdoor use. Recently, several clients have opted for this treatment to extend the lifespan of their customized aluminum parts used in outdoor applications.  

Anodizing is undoubtedly an essential surface treatment for aluminum CNC parts. From regular anodizing and hard anodizing to colored and UV-resistant anodizing, each method offers varying levels of protection and decorative effects. Choosing the right anodizing process based on specific product requirements can significantly enhance the performance and value of customized aluminum parts. At MQJM, we leverage our expertise and extensive experience to deliver high-quality China CNC milling service and anodized aluminum processing services, providing optimal solutions for a wide range of industries.