Si vous êtes ingénieur produit ou spécialiste des achats, choisir le mauvais matériau pour l’usinage CNC peut faire dérailler votre projet: les pièces peuvent se fissurer sous l'effet du stress, coûte plus que prévu, ou ne répondent pas aux normes de l'industrie. La bonne nouvelle? Ce guide simplifie la sélection des matériaux d'usinage CNC avec des catégories claires, exemples concrets, 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 (métal, polymère, or alloy) for your part based on its purpose, besoins de performances, et le coût. Contrairement au moulage par injection (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, usinabilité, and cost directly impact your project’s success.
The most common CNC machining materials fall into five categories: aluminium alloys, acier, acier inoxydable, copper and brass, titane, et polymères. Each has unique pros, inconvénients, and ideal use cases—let’s break them down.
1. Key CNC Machining Material Categories (With Pros, Inconvénients, 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, facile à couper, 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 | Résistance à la traction | Avantages clés | Ideal Use Cases | Price Range |
| EN AW-6061 / 3.3211 | 180 MPa | Haute résistance, bonne résistance à la corrosion | Scaffolding, composants aérospatiaux | € |
| EN AW-6060 / 3.3206 | Faible | Good weldability, cold-forming ability | Éclairage, meubles, flooring | € |
| EN AW-7075 / 3.4365 | 57 MPa | Haute résistance, résistance à la fatigue | Aircraft structural parts | € |
| EN AW-5083 / 3.3547 | – | Excellente résistance à la corrosion | Pièces marines, 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 Résistance à la traction MPa (enough to resist impacts) and was still 30% plus léger que l'acier. The switch cost €0.50 more per frame but reduced crash-related failures by 80%.
Acier: 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 | Résistance à la traction | Avantages clés | Ideal Use Cases | Price Range |
| 1.0503 / C45 (S45C) | 630 MPa | Haute résistance, good dimensional accuracy | Vis, exercices, arbres | €€ |
| 1.0570 / St52-3 | 680 MPa | Haute conductivité électrique | Pièces structurelles, parenthèses | €€ |
| 1.7225 / 42CrMo4 | – | Haute ténacité, résistance aux chocs | Arbres de transmission, large plastic molds | €€ |
| 1.7131 / 16MnCr5 | 600 MPa | High surface hardness, résistance à l'usure | Engrenages, worms, bagues | €€ |
Acier inoxydable: 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, nourriture, ou des produits chimiques.
Top Stainless Steels for CNC Machining
| Stainless Steel Grade | Résistance à la traction | Avantages clés | Ideal Use Cases | Price Range |
| 1.4301 / 304 (V2A) | 590 MPa | Bonne usinabilité, easy to shape | Kitchen sinks, tuyaux, pots | €€€ |
| 1.4404 / 316L (V4A) | – | Chlorine resistance, résistance à la chaleur | Équipement de transformation des aliments, boat parts | €€€ |
| 1.4571 / X6CrNiMoTi17-12-2 | – | Stable at 800°C+, marine resistance | Composants marins, 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 | Résistance à la traction | Avantages clés | Ideal Use Cases | Price Range |
| 2.0060 / E-Cu57 | 360 MPa | Haute conductivité électrique | Jeux de barres, moteurs, windings | €€€ |
| CW004A / 2.0065 | – | Easy to shape into profiles/sheets | Electrical/electronics parts | €€€ |
| 2.0401 / CuZn39Pb3 (Ms58) | – | Good thermoformability, weldable | Hygienic industry parts, composants du moteur | €€ |
Titane: 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 | Résistance à la traction | Avantages clés | Ideal Use Cases | Price Range |
| Grade 2 / DANS 3.7035 | – | Excellent strength-to-weight, biocompatible | Implants médicaux, weight-reducing structures | €€€€€ |
| Grade 5 / 6Al-4V | – | Haute résistance, seawater resistance | Subsea oil/gas structures, pièces aérospatiales | €€€€€ |
Polymères: Affordable and Versatile for Low-Stress Parts
Polymères (plastiques) are cheap, léger, 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 | Avantages clés | Ideal Use Cases | Price Range |
| ABS | Good chemical resistance, stabilité dimensionnelle | Food processing parts, boîtiers | € |
| Acrylique (PMMA) | Transparent (like glass), esthétique | Signalisation, face shields, affiche | € |
| POM (Acétal) | Résistant à l'usure, good in wet environments | Bagues, clamps, pièces électriques | € |
| COUP D'OEIL | Résistance aux hautes températures, résistance chimique | Médical, pièces aérospatiales | €€€ |
| Téflon (PTFE) | Résistance aux températures extrêmes, faible friction | Engrenages, 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 acier (680 MPa) ou titanium Grade 5.
- Will it touch water/chemicals? Go with acier inoxydable 1.4404 (316L) ou cuivre 2.0060.
- Does it need to be lightweight? Optez pour aluminium 6061 ou titanium Grade 2.
- Is electrical conductivity key? Pick cuivre 2.0060 ou laiton 2.0401.
2. What’s Your Budget? (Coût par rapport. Valeur)
Materials range from cheap (aluminium, ABS) to expensive (titane, high-grade stainless steel). Par exemple:
- A simple bracket: Utiliser ABS (€) ou 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? (Usinabilité)
Some materials are harder to cut than others, which adds time and cost. Par exemple:
- POM (Acétal) 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? (Conformité)
- Food industry: Utiliser acier inoxydable 1.4301 (304) ou 1.4404 (316L)—they’re food-safe.
- Industrie médicale: Choisir titanium Grade 2 (biocompatible) ou COUP D'OEIL (résistant aux produits chimiques).
- Aérospatial: Go with aluminium 7075 ou 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 mois, the brackets cracked, leading to fuel leaks. They had to recall 10,000 parties, 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
Chez Yigu Technologie, we believe CNC material selection is a balance of performance, coût, et usinabilité. For clients, we start with the part’s purpose—never just cost. Par exemple, 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 (par ex., parenthèses, boîtiers), aluminium 6060 (métaux) ou ABS (polymères) 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—acier inoxydable 1.4404 (316L) is often used for non-implant parts (par ex., poignées d'outils chirurgicaux). 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.