How does arc anodizing integrate with die casting and CNC workflows?
A Sequenced Workflow for Maximum Component Performance
Arc Anodizing is not a standalone process but the crucial final step in an integrated manufacturing chain that begins with Aluminum Die Casting and is refined by CNC Machining. The integration is sequential and interdependent, designed to build a high-performance component from the substrate up.
Stage 1: Die Casting - The Foundation
The workflow begins with high-pressure die casting to create the part's near-net shape. Successful integration here is paramount:
Alloy Selection: Choosing a compatible alloy like A360 is critical. Its lower silicon content, compared to standard A380, allows for the formation of a more uniform and continuous ceramic coating during arc anodizing, free from the weak spots caused by un-oxidized silicon particles.
Process Control: The die casting process must be optimized to produce a high-integrity surface with minimal porosity. Subsurface defects will be magnified during the high-voltage anodizing process, potentially leading to coating failure.
Stage 2: CNC Machining - Precision Preparation
After casting, the part moves to Post Machining. This step is performed before anodizing for several key reasons:
Dimensional Accuracy: Critical features like threaded holes, tight-tolerance bores, and sealing surfaces are machined to their final dimensions. Attempting to machine through the hard, brittle ceramic coating after anodizing is impractical and would destroy cutting tools.
Deburring and Surface Finishing: Sharp edges and parting lines from the casting are removed. This is vital because the arc anodizing process has a "throwing power" limitation; it builds up more on edges and may not adequately coat deep, narrow valleys. Proper edge-breaking ensures a more consistent coating thickness.
Exposing Base Material: Machining reveals the pristine, non-oxidized aluminum substrate in specific areas. This is essential for achieving electrical conductivity for grounding or for creating precise sealing surfaces where the anodized layer would be undesirable.
Stage 3: Arc Anodizing - The Final Functional Layer
With the part machined to its final geometry, it undergoes the arc anodizing process. The coating grows inward and outward from the existing surface, adding the final functional properties:
Enhanced Wear Resistance: The extremely hard ceramic surface protects the part from abrasion, which is especially important for moving components.
Superior Corrosion Protection: The thick, dense, and fully sealed oxide layer provides a robust barrier against harsh environments, validated by extensive Post Process testing like salt spray.
The key to integration is that the anodizing process uniformly coats the entire part, including the freshly machined features, ensuring complete coverage and protection.
The Value of Integration in Design and Production
This seamless workflow is a core component of our One-Stop Service. It allows for efficient Mass Production of durable components by ensuring that design intent, material selection, and manufacturing processes are all aligned from the initial die castings Design service phase. This integrated approach eliminates compatibility issues and delivers a final part where the structural integrity of the die casting, the precision of the CNC machining, and the superior surface properties of the arc anodizing work in concert.
