If you’re a product engineer or procurement specialist, choosing the wrong material for CNC machining can derail your project: parts might crack under stress, cost more than budgeted, or fail to meet industry standards. The good news? This guide simplifies CNC machining material selection with clear categories, real-world examples, and data-driven tips to help you pick the right material—every time.
What Is CNC Machining Material Selection?
CNC machining material selection is the process of picking the best material (metal, polymer, or alloy) for your part based on its purpose, performance needs, and cost. Unlike injection molding (which uses molten materials), CNC machining is a subtractive process—it cuts away material from a solid block to shape your part. This means the material’s strength, machinability, and cost directly impact your project’s success.
The most common CNC machining materials fall into five categories: aluminium alloys, steel, stainless steel, copper and brass, titanium, and polymers. Each has unique pros, cons, and ideal use cases—let’s break them down.
1. Key CNC Machining Material Categories (With Pros, Cons, and Use Cases)
Not all materials work for every CNC project. Below is a detailed breakdown of each category, including critical specs like tensile strength and cost, to help you narrow down your options.
Aluminium Alloys: Lightweight and Cost-Effective
Aluminium alloys are the most popular choice for CNC machining—they’re lightweight, easy to cut, and affordable. They’re ideal for parts that need low weight but don’t face extreme stress.
Top Aluminium Alloys for CNC Machining
| Alloy Grade | Tensile Strength | Key Benefits | Ideal Use Cases | Price Range |
| EN AW-6061 / 3.3211 | 180 MPa | High strength, good corrosion resistance | Scaffolding, aerospace components | € |
| EN AW-6060 / 3.3206 | Low | Good weldability, cold-forming ability | Lighting, furniture, flooring | € |
| EN AW-7075 / 3.4365 | 57 MPa | High strength, fatigue resistance | Aircraft structural parts | € |
| EN AW-5083 / 3.3547 | – | Excellent corrosion resistance | Marine parts, offshore structures | € |
Real-World Example: A Drone Manufacturer’s Choice
A drone company needed a lightweight frame that could handle small impacts. They first tested EN AW-6060 (cheap but low strength)—the frames bent during flight tests. They switched to EN AW-6061, which had 180 MPa tensile strength (enough to resist impacts) and was still 30% lighter than steel. The switch cost €0.50 more per frame but reduced crash-related failures by 80%.
Steel: Strong and Durable for High-Stress Parts
Steel is a go-to for parts that need high strength and durability, like shafts or gears. It’s heavier than aluminium but offers better performance in high-load applications.
Top Steels for CNC Machining
| Steel Grade | Tensile Strength | Key Benefits | Ideal Use Cases | Price Range |
| 1.0503 / C45 (S45C) | 630 MPa | High strength, good dimensional accuracy | Screws, drills, shafts | €€ |
| 1.0570 / St52-3 | 680 MPa | High electrical conductivity | Structural parts, brackets | €€ |
| 1.7225 / 42CrMo4 | – | High toughness, impact resistance | Gear shafts, large plastic molds | €€ |
| 1.7131 / 16MnCr5 | 600 MPa | High surface hardness, wear resistance | Gears, worms, bushings | €€ |
Stainless Steel: Corrosion-Resistant for Harsh Environments
Stainless steel adds chromium (and often molybdenum) to steel, making it resistant to rust and chemicals. It’s perfect for parts that touch water, food, or chemicals.
Top Stainless Steels for CNC Machining
| Stainless Steel Grade | Tensile Strength | Key Benefits | Ideal Use Cases | Price Range |
| 1.4301 / 304 (V2A) | 590 MPa | Good machinability, easy to shape | Kitchen sinks, pipes, pots | €€€ |
| 1.4404 / 316L (V4A) | – | Chlorine resistance, heat resistance | Food processing equipment, boat parts | €€€ |
| 1.4571 / X6CrNiMoTi17-12-2 | – | Stable at 800°C+, marine resistance | Marine components, offshore parts | €€€€ |
Copper and Brass: High Conductivity for Electrical Parts
Copper and brass excel at conducting electricity and heat. They’re easy to machine and have good corrosion resistance—ideal for electrical components.
Top Copper/Brass Alloys for CNC Machining
| Alloy Grade | Tensile Strength | Key Benefits | Ideal Use Cases | Price Range |
| 2.0060 / E-Cu57 | 360 MPa | High electrical conductivity | Busbars, motors, windings | €€€ |
| CW004A / 2.0065 | – | Easy to shape into profiles/sheets | Electrical/electronics parts | €€€ |
| 2.0401 / CuZn39Pb3 (Ms58) | – | Good thermoformability, weldable | Hygienic industry parts, engine components | €€ |
Titanium: High Strength-to-Weight for Medical/Aerospace
Titanium is lightweight (half the weight of steel) but incredibly strong. It’s biocompatible (safe for the human body) and corrosion-resistant—perfect for medical implants and aerospace parts.
Top Titanium Grades for CNC Machining
| Titanium Grade | Tensile Strength | Key Benefits | Ideal Use Cases | Price Range |
| Grade 2 / EN 3.7035 | – | Excellent strength-to-weight, biocompatible | Medical implants, weight-reducing structures | €€€€€ |
| Grade 5 / 6Al-4V | – | High strength, seawater resistance | Subsea oil/gas structures, aerospace parts | €€€€€ |
Polymers: Affordable and Versatile for Low-Stress Parts
Polymers (plastics) are cheap, lightweight, and easy to machine. They’re great for parts that don’t need extreme strength, like enclosures or electrical insulators.
Top Polymers for CNC Machining
| Polymer Type | Key Benefits | Ideal Use Cases | Price Range |
| ABS | Good chemical resistance, dimensional stability | Food processing parts, enclosures | € |
| Acrylic (PMMA) | Transparent (like glass), aesthetic | Signage, face shields, displays | € |
| POM (Acetal) | Wear-resistant, good in wet environments | Bushings, clamps, electrical parts | € |
| PEEK | High-temperature resistance, chemical resistance | Medical, aerospace parts | €€€ |
| Teflon (PTFE) | Extreme temperature resistance, low friction | Gears, piston rings, skateboards | €€ |
2. 4 Critical Factors to Choose the Right CNC Material
Picking a material isn’t just about specs—you need to match it to your project’s unique needs. Ask yourself these four questions:
1. What Will the Part Do? (Performance Needs)
- Does it need to resist stress? Choose high-tensile materials like 1.0570 steel (680 MPa) or titanium Grade 5.
- Will it touch water/chemicals? Go with stainless steel 1.4404 (316L) or copper 2.0060.
- Does it need to be lightweight? Opt for aluminium 6061 or titanium Grade 2.
- Is electrical conductivity key? Pick copper 2.0060 or brass 2.0401.
2. What’s Your Budget? (Cost vs. Value)
Materials range from cheap (aluminium, ABS) to expensive (titanium, high-grade stainless steel). For example:
- A simple bracket: Use ABS (€) or aluminium 6060 (€) to save money.
- A medical implant: Invest in titanium Grade 2 (€€€€€)—it’s biocompatible and worth the cost to avoid failures.
3. How Easy Is It to Machine? (Machinability)
Some materials are harder to cut than others, which adds time and cost. For example:
- POM (Acetal) is the easiest polymer to machine—fast and low-waste.
- Titanium Grade 5 is hard to machine—needs special tools, increasing lead time by 2–3 days.
4. What Industry Standards Apply? (Compliance)
- Food industry: Use stainless steel 1.4301 (304) or 1.4404 (316L)—they’re food-safe.
- Medical industry: Choose titanium Grade 2 (biocompatible) or PEEK (chemical-resistant).
- Aerospace: Go with aluminium 7075 or titanium Grade 5—they meet aerospace strength standards.
3. Real-World Mistake to Avoid: Choosing Cost Over Performance
A automotive parts supplier once chose ABS (cheap polymer) for a fuel line bracket because it cost €1 less per part than Nylon. But ABS isn’t resistant to gasoline—after 6 months, the brackets cracked, leading to fuel leaks. They had to recall 10,000 parts, costing $200,000.
The fix? Switching to Nylon (€€), which is hydrocarbon-resistant. The extra €1 per part saved them from a costly recall. The lesson: Don’t sacrifice performance for a lower price—choose the material that fits the part’s job.
Yigu Technology’s Perspective on CNC Machining Material Selection
At Yigu Technology, we believe CNC material selection is a balance of performance, cost, and machinability. For clients, we start with the part’s purpose—never just cost. For example, we often guide procurement teams away from cheap aluminium for high-stress parts and toward 42CrMo4 steel instead. We also share material spec sheets early to avoid compliance issues. The best results come from collaboration: engineers share performance needs, we share material expertise, and together we pick a solution that works—on time and on budget.
FAQ About CNC Machining Material Selection
1. What’s the most cost-effective material for CNC machining?
For most low-stress parts (e.g., brackets, enclosures), aluminium 6060 (metals) or ABS (polymers) are the cheapest and easiest to machine. They balance cost and basic performance.
2. Can I use stainless steel for medical parts?
Only specific grades—stainless steel 1.4404 (316L) is often used for non-implant parts (e.g., surgical tool handles). For implants, titanium Grade 2 is better because it’s biocompatible (safe for long-term body contact).
3. Why is PEEK more expensive than other polymers?
PEEK is expensive because it can withstand high temperatures (works in hot water/steam) and has excellent chemical resistance—properties that make it ideal for medical and aerospace parts. Cheaper polymers like ABS can’t match this performance.
