Materials Selection Guide for CNC Machining

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Selecting the optimal material is a foundational step in any CNC machining project, directly impacting the part's functionality, durability, cost, and lead time. As a professional onestopshop for custom CNC machined parts, we understand that this critical decision can be complex. This guide outlines key material families to help you make an informed choice for your next project.


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1. Metals: The Powerhouses of Precision

Aluminum Alloys: The most popular choice for CNC machining, aluminum offers an excellent strengthtoweight ratio, good corrosion resistance, and superior machinability. Alloys like 6061 and 7075 are industry standards. 6061 is a versatile, generalpurpose alloy, while 7075 provides higher strength, comparable to many steels, making it ideal for aerospace and highstress applications. Its fast machining speeds lead to lower production costs.
Stainless Steels: Chosen for their exceptional corrosion resistance and strength. Grades like 304 and 316 are common for medical, marine, and food processing equipment. 303 stainless steel is specifically formulated for even better machinability, though with slightly lower corrosion resistance. For the highest strength and hardness, precipitationhardening grades like 174 PH are unmatched.
Carbon Steels: Offering high strength and toughness at a lower cost, carbon steels (e.g., 1018, 1045) are perfect for structural components and industrial parts. However, they require plating or coating to prevent rust.
Titanium Alloys: Titanium (e.g., Grade 5, Ti6Al4V) is renowned for its exceptional strengthtoweight ratio, corrosion resistance, and biocompatibility. It is essential for aerospace, medical implants, and highperformance automotive applications. Its challenging machinability requires specialized expertise.


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2. Plastics: Versatile and Specialized

ABS: A tough, impactresistant plastic, excellent for prototyping, enclosures, and consumer goods. It's easy to machine and can be postprocessed (e.g., sanded, painted) easily.
Nylon (PA): Known for its high strength, wear resistance, and low friction. It's ideal for gears, bushings, and insulators.


POM (Acetal/Delrin): This engineering plastic offers high stiffness, low friction, and excellent dimensional stability, making it a prime choice for precision parts like bearings and gears.
PEEK: A highperformance thermoplastic with outstanding thermal resistance, chemical resistance, and mechanical properties. It is used in demanding sectors like aerospace, automotive, and medical technology.

Key Selection Factors:

Mechanical Needs: Consider the required strength, hardness, and impact resistance.
Operating Environment: Account for exposure to chemicals, moisture, UV light, and extreme temperatures.
Weight & Cost: Aluminum and plastics often provide the best balance for weightsensitive and costdriven projects.
Aesthetics & Compliance: Specify if the part needs a specific finish (anodizing, plating) or must meet regulatory standards (e.g., FDA, USP Class VI).

Partnering with an expert manufacturer is crucial. Our engineering team can guide you through this selection process, ensuring your design is optimized for both performance and manufacturability. The right material is the first step toward a successful, highquality component that drives your project forward.