When you’re choosing between CNC machining and casting for producing parts, it’s essential to understand the nature and advantages of each method. They both have unique processes and applications, so choosing the right one could be better suited to your specific needs.
What is CNC Machining?
CNC (Computer Numerical Control) machining is a subtractive manufacturing process.
In CNC machining processes, your part is made by removing material from a solid block, which is called the workpiece. This is done using a variety of cutting tools and CNC machines. These machines are incredibly precise, which means they can create parts that fit extremely tight tolerances, often within +/- 0.0002 inches.
What is Die Casting?
Casting is a formative manufacturing method where metal is melted and poured into a mold to achieve the desired shape. The metal casting process is highly efficient for producing large quantities of parts. It’s a little less precise than CNC machining, but it’s a great choice when you need to create complex, intricate shapes without the high costs of machining.
How to Choose Between CNC Machining and Die Casting?
When selecting between CNC machining and die casting, several key factors determine which process is most suitable for your manufacturing needs.
Production volume is a primary consideration: CNC machining is a better choice for low volume of parts production runs, such as prototypes and small batches, because it incurs no tooling costs, making it perfect for projects with limited quantities.
Conversely, die casting becomes more cost-effective for high volume production due to its consistency and speed, where initial tooling expenses are offset by lower per-unit costs at larger scales.
Material considerations also play a critical role in the decision-making process. CNC machining offers unparalleled versatility, capable of working with virtually any material—including metals, plastics, wood, and composites—making it excellent for producing high-precision parts that require specific material properties.
On the other hand, die casting is generally limited to non-ferrous metals like aluminum, zinc, and copper, which is ideal for parts that demand consistent material properties across extensive production runs.
When it comes to design complexity, CNC machining excels at creating parts with tight tolerances and precise geometries, although it may encounter limitations with certain complex internal features.
In contrast, die casting is superior for manufacturing intricate geometries and thin-walled parts, such as those with minimum wall thicknesses of 0.5mm for aluminum and 0.3mm for zinc, making it well-suited for components with elaborate internal structures.
Cost considerations further differentiate the two processes. CNC machining typically results in higher material waste due to its subtractive nature and involves lower initial setup costs but carries higher per-unit expenses.
Conversely, die casting minimizes material waste and, despite its high initial tooling costs, offers lower per-unit costs when producing large quantities.
Finally, production speed is a decisive factor for manufacturers. CNC machining often requires additional post-processing and program verification for each unique shape, making it slower for high-volume production. In contrast, die casting facilitates much faster production rates for large quantities, with cycle times sometimes reduced to just a few seconds per part.
Applications for CNC Machined Parts and Die Casting Parts
Here’s a comparison table of applications for CNC Machined Parts and Die Casting Parts across different industries:
| Industry | CNC Machined Parts | Die Casting Parts |
| Automotive | Engine blocks, gearbox cases, custom parts for high performance vehicles | Transmission housings, engine components |
| Aerospace | Engine mounts, landing gear components, airfoils | Structural components like fuselage and brackets |
| Medical | Surgical instruments, implants, custom patient-specific components | Medical device housings and components |
| Industrial | Hydraulic system components, metal frames | Pumps, fittings, and housings |
| Consumer Products | Electronics housings, furniture components | Lighting fixtures and decorative hardware |
| Defense | Missile components, transmission parts | Defense-related equipment such as housings |
Why Choose Moldie Casting?
At Moldie Casting, we embrace a collaborative methodology to fully grasp each client’s unique requirements. Through comprehensive consultations and meticulous needs assessments, we ensure that every project is customized to achieve your specific technical and business goals.
In addition, we leverage state-of-the-art die-casting machinery and advanced automation technologies to boost production efficiency and precision. Our extensive range of die-casting services provides a complete, one-stop solution for all your manufacturing needs, streamlining the production process and significantly enhancing overall performance.
To learn more about how Moldie Casting can support your manufacturing endeavors, please visit our website.
Frequently Asked Questions
How does the strength of cast parts compare to those machined by CNC?
Generally, CNC machined parts are stronger than cast parts. This strength comes from the use of solid blocks of material and the absence of potential defects like porosity that can occur in casting.
Can CNC machining match the strength of forged components?
While the strength of CNC machined parts is high, forged components are typically stronger due to the compression of the metal, which aligns with the grain flow and enhances the strength of the final part.
What are the main benefits of choosing machining for metal parts overcasting?
Machining’s primary benefits include superior precision, the versatility of materials that can be used, and the greater strength of the final product. It is also favored for small quantities due to its ability to efficiently produce one-offs and prototypes.