When designing or sourcing automotive components, one of the biggest decisions is choosing the right manufacturing process — CNC machining or die casting.
Both methods can produce high-quality aluminum parts, but the right choice depends on your project’s volume, tolerance, cost, and material requirements.
Here’s a practical guide to help you decide which process fits your needs.
1.What Is CNC Machining?
CNC machining (Computer Numerical Control) uses computer-programmed cutting tools to remove material from a solid block — usually aluminum or steel — to create precise, custom-shaped parts.
Advantages:
- Excellent dimensional accuracy (±0.01 mm typical)
- Ideal for prototypes, low- to mid-volume production, or tight-tolerance areas
- Compatible with various materials (aluminum, stainless steel, brass, plastics)
- Smooth surface finish ready for anodizing or polishing
Limitations:
- Higher cost per part at large volumes
- More material waste (subtractive process)
- Longer machining time for complex shapes
2.What Is Die Casting?
Die casting involves injecting molten aluminum or zinc alloy into a steel mold (die) under high pressure.
Once cooled, the part is ejected from the mold, producing near-net-shape components with excellent repeatability.
Advantages:
- Cost-effective for high-volume production
- Excellent dimensional consistency and repeatability
- Smooth surface finish suitable for painting, polishing, or coating
- High mechanical strength with lightweight aluminum alloys
Limitations:
- Higher initial tooling cost (for the mold)
- Limited material selection (mainly ADC12, A380, etc.)
- Some porosity may appear if not controlled properly
3.CNC Machining vs Die Casting: A Quick Comparison
4.When to Choose CNC Machining
Choose CNC machining if:
- You need prototypes or low-volume production
- You require tight tolerances and high precision
- You plan to validate the design before making molds
- You expect frequent design changes or custom orders
Examples:
Fuel caps, fasteners, prototypes, custom racing parts, small-series batches for EV systems.
5.When to Choose Die Casting
Choose die casting if:
- You need mass production with consistent quality
- You’re making parts with complex geometry and thin walls
- You require lightweight aluminum components with strength and rigidity
- Your product line will stay stable for long-term supply
Examples:
Battery housings, cooling plates, structural covers, EV connectors, and decorative trims.
6.Why Many Projects Combine Both Processes
Many successful automotive programs use a hybrid approach:
They produce near-net-shape parts with die casting, then apply CNC machining on critical surfaces or threads for accuracy.
This combination:
- Reduces total cost
- Ensures high precision where needed
- Maintains strong mechanical performance
7.Choosing the Right Partner
A capable supplier should offer both CNC and die casting services under one roof, ensuring smooth transition from prototype to mass production.
At Wometal, we provide:
- CNC machining, high-pressure die casting, and surface finishing in-house
- DFM support to optimize wall thickness, draft, and tolerance
- CMM inspection, PPAP, and material traceability
Expertise in automotive components for cars, trucks, buses, EVs, and racing vehicles
8.Conclusion
Both CNC machining and die casting play vital roles in modern automotive component manufacturing.
The key is understanding your volume, precision, and cost targets — and partnering with a manufacturer who can guide you through both processes.
With the right balance, you’ll achieve efficiency, performance, and long-term product reliability.
👉 “Learn more about our automotive components.