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Metal CNC machining is valued for one simple reason: almost any engineering metal can be turned into a precise, functional part. But "almost any" does not mean "all the same." Each metal behaves differently on the machine, carries a different cost profile, and suits different end uses. Knowing what can be processed, and what each material is good for, helps you specify parts that are easier to manufacture, more reliable in service, and better value for money. This guide walks through the metals most commonly processed with CNC machining, their key properties, typical grades, and where they are used.
Aluminum is the workhorse of CNC machining. It offers an excellent strength-to-weight ratio, natural corrosion resistance, good thermal and electrical conductivity, and outstanding machinability, which keeps cycle times and tooling costs low.
The most frequently machined grades include 6061-T6, a versatile general-purpose alloy used for brackets, housings, and fixtures; 7075-T6, a high-strength aerospace-grade alloy that approaches the strength of some steels at roughly one-third of the weight; and 6082, popular in structural applications. Aluminum parts can also be anodized for extra surface hardness and corrosion protection. Typical uses range from aerospace frames and automotive components to electronics enclosures and automation equipment.
Stainless steel combines high strength, wear resistance, and excellent corrosion resistance, making it the default choice for medical devices, food equipment, marine hardware, and chemical processing parts. It is harder to machine than aluminum and demands rigid setups and appropriate tooling, but the resulting parts are durable and hygienic.
Common machinable grades include 303, a free-cutting grade ideal for high-volume turned parts such as fasteners, shafts, and fittings; 304, the general-purpose austenitic grade; 316L, which offers superior resistance to chlorides and is widely used in marine and medical applications; and 440, a martensitic grade that can be heat-treated to high hardness for wear-resistant components like bearings and valve parts.
Carbon and alloy steels deliver high strength and toughness at a relatively low material cost, which makes them staples for shafts, gears, structural components, and fixtures. The trade-off is that they are not inherently corrosion-resistant, so they usually need plating, blackening, painting, or another surface treatment.
Frequently machined grades include mild steels such as 1018 and 1020, medium-carbon 1045 for stronger shafts and axles, and alloy steels like 4140 and 4340 for high-stress parts that demand superior fatigue strength and toughness. Grades such as 8620 and 9310 are common choices for case-hardened gears and transmission components.
Brass is one of the easiest metals to machine. Grades such as C360 and C260 cut cleanly, produce minimal tool wear, and hold fine detail, which is why brass is the preferred material for precision fittings, connectors, valve components, and decorative hardware. It also offers good corrosion resistance and natural electrical conductivity.
Pure copper, including grades like C110 and 101, is chosen when electrical or thermal conductivity is the priority, for example in busbars, heat sinks, and electrical contacts. Its high ductility makes it gummy to cut, so sharp tooling and the right cutting parameters are essential for clean results.
Titanium, particularly the Ti-6Al-4V (Grade 5) alloy, offers the highest strength-to-weight ratio of any commonly machined metal, along with excellent corrosion resistance and biocompatibility. It is a premium choice for aerospace structures, medical implants, and high-performance motorsport parts.
Titanium is also genuinely difficult to machine: it conducts heat poorly, so heat concentrates at the cutting edge, and it work-hardens if the tool dwells. Successful titanium CNC machining requires rigid machines, sharp carbide tooling, controlled feeds and speeds, and generous coolant, all of which add to cost but are routine in an experienced shop.
Magnesium is the lightest structural metal, roughly one-third lighter than aluminum, and it machines exceptionally fast. It is used where every gram matters, such as aerospace housings, drone components, and portable equipment. Machining magnesium requires proper chip handling and housekeeping because fine magnesium chips are flammable, but with correct practices it is processed safely and efficiently.
Tool steels such as Toolox 33 and Toolox 44 are pre-hardened steels designed for molds, dies, jigs, and high-wear tooling components. They machine predictably and keep their hardness without additional heat treatment, shortening lead times for tooling projects.
Tungsten is extremely dense, hard, and heat-resistant, which makes it valuable for counterweights, radiation shielding, and high-temperature tooling. It is abrasive and challenging to cut, so it is typically handled with rigid setups and, where geometry allows, processes like wire EDM that cut hard conductive metals without mechanical cutting forces.
With so many options, selection comes down to balancing a few practical factors:
Metal CNC machining can process a remarkably wide range of materials: aluminum, stainless steel, carbon and alloy steels, brass, copper, titanium, magnesium, tool steel, and tungsten, each with distinct strengths and machining considerations. The right choice depends on your part's mechanical demands, environment, weight targets, and budget.
At ANOK Precision Manufacturing, our metal CNC machining service covers all of the materials above, from free-cutting aluminum and brass to difficult alloys like Ti-6Al-4V and Inconel. As an ISO 9001:2015 certified factory, we hold tolerances down to ±0.002 mm across CNC milling, turning, surface grinding, and wire EDM. Whether you need stainless steel CNC machining for medical components or titanium CNC machining for aerospace parts, send us your drawings for a free DFM review and quotation.