The Power of Surface Finishes

A CNC machined component is the first step – its surface finish defines how it interacts with the world. From sleek automotive trim that catches the eye to aerospace components that defy corrosive environments, the right finish transforms a raw part into a high-performance product. With a wide range of options, making the right selection is crucial.

Surface roughness is a quantitative measure of a part's texture. Ra (roughness average) is the most common metric, expressed in micrometers (μm) or microinches (μin). Here's a general guideline to help you interpret these values:

• As-Machined (3.2 μm - 1.6 μm / 125 μin - 63 μin): The baseline finish with visible tool marks.
  
  
• Smooth Finishes ( 0.8 μm - 0.4 μm / 32 μin - 16 μin): Surfaces that feel smooth to the touch, ideal for sliding components and enhanced aesthetics.
  
  
• Ultra-Smooth Finishes (0.2μm - 0.1 μm / 8 μin - 4 μin): Polished or mirror-like finishes often required for critical sealing surfaces, medical parts, or purely luxurious aesthetics.

Let's explore the range of finishing processes that can transform your CNC machined parts:

1) Abrasive Techniques:

• Bead Blasting: Versatile and adaptable, with different media options to achieve satin, matte, or pre-coating preparation finishes.
  
  
• Sanding & Polishing: Progressive use of finer abrasives for smoothness, or targeted polishing of specific features.
  
  
• Vibratory/Mass Finishing: Ideal for bulk parts, offering edge deburring, smoothing, and some polishing, depending on media and cycle time.
  

2) Coatings:

• Anodizing (Aluminum): Type II for color and moderate protection, Type III ("hardcoat") for superior wear and corrosion resistance.
  
  
• Powder Coating: Durable and customizable, with a vast range of colors, textures, and functionality.
  
  
• Painting: Offers flexibility in color, sheen, and patterns. Wet spray painting achieves high-quality aesthetic finishes.

• Function: Will the part endure friction, chemicals, or weather? Is visual appeal paramount?
  
  
• Material: Some finishes are material-specific (e.g., plating options may vary based on the substrate metal).
  
  
• Budget: More complex finishes often incur higher costs. Balance your ideal result with what's financially feasible.
  
  
• Batch Size: Some finishes lend themselves better to small batches, others excel with large quantities.

Norck understands that exceptional products demand exceptional finishes. Here's why we're your ideal partner:

• Design for Finishing: Norck's engineers proactively suggest design tweaks to optimize surface finish success and cost-efficiency.
  
  
• In-House Expertise: A wide range of finishing capabilities within the Norck network simplifies your process and ensures consistent quality.
  
  
• Materials Matter: Norck's global material access and finishing knowledge help you navigate even the most unique material-finish combos.
  
  
• Precision Metrology: Advanced equipment verifies that your finished parts meet exact roughness (Ra) or aesthetic specifications.