Why does aluminum die casting require CNC precision machining?

Aluminum die casting is an efficient metal forming process that can quickly produce near-net-shape parts. However, the die-casting process itself has some problems such as dimensional tolerance, surface accuracy, and internal structure limitations. Therefore, it is still necessary to further improve the quality through **CNC precision machining (computer numerical control machining)** to meet the requirements of precision parts.

 

The main reasons why CNC machining is required after aluminum die casting:

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1. Improve dimensional accuracy and meet strict tolerance requirements

Although die casting can achieve high dimensional accuracy, there are still certain shrinkage and deformation problems, especially for precision assembly parts such as threaded holes, bearing seats, etc., which require CNC processing to correct the size.

CNC machining can achieve an accuracy of ±0.01mm or even higher, ensuring the precise fit of parts with other components.

 

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2. Processing details and internal structure

Due to the limitations of die-casting molds, some internal structures (such as deep holes, grooves, threads, precision chamfers, etc.) cannot be made directly through die-casting and require subsequent CNC processing to complete.

For example: threaded holes, positioning holes, guide grooves, etc., if directly formed by die casting, the accuracy and strength may be insufficient, so CNC trimming is required.

 

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3. Correction of deformation and surface flatness

Aluminum die castings may deform slightly during the cooling process due to internal stress in the metal, especially parts with large areas or thin-walled structures.

CNC machining can remove excess material, make the surface smooth, and ensure the size meets the standard, thus ensuring the assembly accuracy of parts.

 

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4. Improve surface finish and quality

The surface of die castings may have slight burrs, pores, textures or defects, and CNC machining can further trim them to make the surface smoother and more delicate, which is especially suitable for high-end products or parts that require high texture.

After CNC processing, surface treatments such as polishing and anodizing can be performed to make the appearance more beautiful and improve durability.

 

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5. Enhance mechanical performance and reliability

Certain key stress-bearing parts require higher mechanical strength, such as automotive parts and aerospace components. CNC processing can optimize the contact surface and improve structural stability and durability.

Especially for parts that require high-strength connections (such as precision mechanical accessories and parts requiring airtightness), CNC machining can ensure that they can withstand greater loads without failure.

 

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Aluminum die casting is an efficient forming technology, but to achieve high precision, high strength, precision structure and excellent surface quality, CNC precision machining is still required for further finishing and optimization. CNC machining can ensure that die-casting parts meet dimensional tolerance requirements, assembly accuracy, mechanical properties and appearance quality. Therefore, in high-end industries such as aviation, automobiles, and electronic equipment, aluminum die-casting and CNC machining are usually used in combination as standard process flows.