Post Processing for CNC Machined Aluminum Parts

CNC machining delivers exceptionally precise and complex aluminum parts directly from the digital file. However, the raw machined state often requires additional finishing touches to meet final application requirements. This secondary stage, known as postprocessing, is critical for enhancing a part's functionality, durability, and aesthetics. For businesses seeking reliable, productionready components, understanding these options is key.


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Why is PostProcessing Essential?

While "asmachined" parts are functional, they have visible tool marks and a matte, textured surface. Postprocessing addresses this by:

Improving Corrosion Resistance: Aluminum naturally forms a protective oxide layer, but it can be insufficient for harsh environments.
Enhancing Wear Resistance: Treatments can significantly harden the surface, reducing abrasion and extending part life.
Modifying Surface Appearance: From a sleek, professional look to specific colors, finishing defines the product's visual identity.

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Facilitating Paint Adhesion: A properly prepared surface ensures coatings like paint and powder coat adhere effectively and last longer.
Achieving Specific Dimensions: Processes like vibratory tumbling can deburr and break sharp edges for safety and function.

Common PostProcessing Techniques for Aluminum



Selecting the right finish depends on the part's enduse. Here are some of the most effective methods:

1. Bead Blasting: This process propels fine glass beads at the part to create a uniform, satinmatte surface. It is excellent for removing minor tool marks and providing a consistent, nonreflective base for further anodizing or painting.

2. Anodizing (Type II & III): This is the most prevalent and recommended finish for aluminum. It is an electrochemical process that thickens the part's natural oxide layer.
Type II (Decorative Anodizing): Offers excellent corrosion resistance and allows for a wide range of color dyes (black, red, blue, etc.). It provides a durable, scratchresistant layer suitable for consumer products and internal components.
Type III (Hard Anodizing): Creates a much thicker, harder coating that is exceptionally wearresistant. It is ideal for highstress applications like military, aerospace, and automotive components, though it has limited color options.

3. Powder Coating: This involves applying a dry electrostatically charged powder to the part and then curing it in an oven to form a thick, durable, and attractive polymer layer. It is available in an almost limitless range of colors and textures (e.g., glossy, matte, metallic) and provides superior protection against impacts and chemicals.

4. Chemical Film Conversion Coating (e.g., Alodine/Chromate): This thin, conductive coating provides good corrosion resistance and is an outstanding primer for paint adhesion. It is widely used in the aerospace and electronics industries.

Partner with a Pro for Flawless Finishes

Choosing the incorrect postprocess can lead to part failure, increased costs, and project delays. As your onestop CNC machining partner, we don't just deliver precise parts; we provide expert guidance on the optimal finishing solution for your project's budget, performance, and aesthetic goals. Let us help you transform your CNC machined aluminum parts into highperformance, marketready products.