CNC Machining Materials Guide: How to Choose the Right Metal for Your Project

Choosing the right material is one of the most critical decisions in any CNC machining project. The material you select affects everything from part strength and weight to cost and lead time. At Mohan Machining & Manufacturing in Sacramento, CA, we work with a wide range of metals and alloys to deliver precision parts for aerospace, medical, automotive, and industrial applications.

In this guide, we break down the most commonly machined metals, their properties, and when to use each one.

Aluminum (6061 and 7075)

Aluminum is the most popular CNC machining material, and for good reason. It machines quickly, is lightweight, corrosion-resistant, and cost-effective. 6061 aluminum is the go-to general-purpose alloy, offering excellent machinability and weldability, making it ideal for brackets, housings, and structural components. 7075 aluminum is significantly stronger and is commonly used in aerospace and high-stress applications where strength-to-weight ratio matters most.

Stainless Steel (303, 304, and 316)

Stainless steel is chosen when corrosion resistance and durability are top priorities. 303 stainless is the easiest to machine and works well for fittings, shafts, and fasteners. 304 stainless offers better corrosion resistance and is widely used in food processing and medical equipment. 316 stainless provides the highest corrosion resistance, especially against saltwater and chemicals, making it essential for marine, pharmaceutical, and chemical processing applications. Stainless steel takes longer to machine than aluminum and costs more, but its performance in harsh environments is unmatched.

Carbon Steel and Tool Steel

Carbon steels like 1018 and 1045 offer excellent strength and are easy to machine, making them a budget-friendly choice for jigs, fixtures, shafts, and structural parts. Tool steels such as A2, D2, and O1 are engineered for extreme hardness and wear resistance, making them ideal for dies, molds, punches, and cutting tools. These materials are harder to machine and may require heat treatment, but they deliver exceptional performance in demanding tooling and manufacturing applications.

Titanium

Titanium offers an unbeatable combination of high strength, low weight, and outstanding corrosion resistance. Grade 5 titanium (Ti-6Al-4V) is the most commonly machined titanium alloy and is widely used in aerospace, medical implants, and high-performance automotive parts. Titanium is more expensive and more difficult to machine than aluminum or steel, requiring specialized tooling and slower cutting speeds. However, for applications where performance and weight savings are critical, there is no substitute.

Brass and Copper

Brass is one of the easiest metals to machine, producing smooth finishes with minimal tool wear. It is widely used for electrical connectors, plumbing fittings, valves, and decorative hardware. Copper is prized for its excellent thermal and electrical conductivity, making it essential for heat sinks, electrical bus bars, and RF components. Both materials machine beautifully and are a great choice when conductivity or aesthetics are important.

How to Choose the Right Material

When selecting a material for your CNC machined parts, consider these key factors: What environment will the part operate in? Does it need to resist corrosion, heat, or chemical exposure? What mechanical loads will the part experience? Is weight a concern? What is your budget and timeline? Harder materials take longer to machine and cost more. A good machine shop will help you balance performance requirements with cost and manufacturability. At Mohan Machining, we regularly consult with customers on material selection to ensure the best outcome for every project.

Get a Free Quote from Mohan Machining

Whether you need aluminum prototypes, stainless steel production runs, or complex titanium components, Mohan Machining & Manufacturing has the equipment and expertise to deliver. We offer 3-axis and 5-axis CNC milling, CNC turning, and full finishing services from our shop in Sacramento, California. Contact us today for a free quote and fast turnaround on your next CNC machining project.